essay about satellite

Essay on Satellite

Students are often asked to write an essay on Satellite in their schools and colleges. And if you’re also looking for the same, we have created 100-word, 250-word, and 500-word essays on the topic.

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100 Words Essay on Satellite

Introduction to satellites.

Satellites are objects in space that orbit around larger bodies, like Earth. They can be natural, like moons, or man-made for various purposes.

Types of Satellites

Importance of satellites.

Satellites are important as they help us in communication, weather forecasting, navigation, and scientific research. They play a crucial role in our daily lives and scientific advancements.

Understanding satellites is fascinating. They are a testament to human ingenuity and our quest to explore the universe.

250 Words Essay on Satellite

Introduction, the science behind satellites.

Satellites operate on the principle of gravity. Launched into space by rockets, they maintain their orbit around planets due to the balance between their forward motion and the gravitational pull of the planet. The height and speed of the satellite determine the nature of its orbit.

Satellites are broadly classified into natural and artificial. Natural satellites are celestial bodies that orbit a planet, like the moon. Artificial satellites, on the other hand, are man-made and serve specific purposes. They can be further divided into categories like communication, weather, navigation, and research satellites.

Applications of Satellites

Satellites have revolutionized our lives. Communication satellites enable global connectivity, facilitating television broadcasts, phone calls, and internet services. Weather satellites provide meteorological data, aiding in weather prediction and climate studies. Navigation satellites like GPS ensure accurate location and timing information. Research satellites contribute to space exploration and scientific discoveries.

In conclusion, satellites have become an indispensable part of our lives. They have not only advanced our understanding of the cosmos but also enhanced our capabilities in communication and navigation. As technology progresses, the potential applications of satellites are bound to increase, paving the way for a future where space technology is even more ingrained in our daily lives.

500 Words Essay on Satellite

Satellites, the celestial bodies orbiting around a planet, have become an integral part of our modern life. They are not only vital for scientific exploration but also for communication, weather monitoring, navigation, and numerous other applications. This essay aims to delve into the world of satellites, their types, uses, and significance.

Understanding Satellites

Satellites can be broadly classified into two categories: natural and artificial. Natural satellites are celestial bodies like moons, while artificial satellites are human-made machines launched into space for specific tasks. Artificial satellites can be further categorized into communication satellites, weather satellites, navigation satellites, reconnaissance satellites, and scientific satellites, among others.

Satellites play a pivotal role in various aspects of our daily lives. Communication satellites have revolutionized global communication by facilitating television broadcasts, telephone calls, and internet services. Weather satellites help predict weather changes, enabling timely disaster warnings and facilitating agricultural planning. Navigation satellites, like those in the GPS system, provide precise positional data for navigation on land, sea, and air. Scientific satellites aid in astronomical observations and earth science studies, providing valuable data about our universe and our planet.

Challenges and Future Prospects

Despite their numerous benefits, the use of satellites comes with its own set of challenges. Space debris, also known as ‘space junk’, is a significant problem. It consists of defunct satellites and fragments from satellite collisions and explosions. This debris poses a threat to functional satellites and manned spacecraft.

Looking ahead, the future of satellites is promising. Developments in technology are paving the way for smaller, more capable satellites. The concept of satellite constellations, a group of satellites working together, is gaining traction. Companies like SpaceX with its Starlink project aim to provide global broadband coverage using these constellations.

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Home — Essay Samples — Information Science and Technology — Digital Era — Satellites And Their Potentials 

Satellites and Their Potentials 

• Categories: Digital Era Information Technology Innovation

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Published: Jan 21, 2020

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A photo-essay from NASA’s Earth Science Division — February 2019 Download Earth in PDF , MOBI (Kindle), or ePub formats.

Of all celestial bodies within reach or view, as far as we can see, out to the edge, the most wonderful and marvelous and mysterious is turning out to be our own planet earth. There is nothing to match it anywhere, not yet anyway. —Lewis Thomas

Sixty years ago, with the launch of Explorer 1, NASA made its first observations of Earth from space. Fifty years ago, astronauts left Earth orbit for the first time and looked back at our “blue marble.” All of these years later, as we send spacecraft and point our telescopes past the outer edges of the solar system, as we study our planetary neighbors and our Sun in exquisite detail, there remains much to see and explore at home.

We are still just getting to know Earth through the tools of science. For centuries, painters, poets, philosophers, and photographers have sought to teach us something about our home through their art.

This book stands at an intersection of science and art. From its origins, NASA has studied our planet in novel ways, using ingenious tools to study physical processes at work—from beneath the crust to the edge of the atmosphere. We look at it in macrocosm and microcosm, from the flow of one mountain stream to the flow of jet streams. Most of all, we look at Earth as a system, examining the cycles and processes—the water cycle, the carbon cycle, ocean circulation, the movement of heat—that interact and influence each other in a complex, dynamic dance across seasons and decades.

We measure particles, gases, energy, and fluids moving in, on, and around Earth. And like artists, we study the light—how it bounces, reflects, refracts, and gets absorbed and changed. Understanding the light and the pictures it composes is no small feat, given the rivers of air and gas moving between our satellite eyes and the planet below.

For all of the dynamism and detail we can observe from orbit, sometimes it is worth stepping back and simply admiring Earth. It is a beautiful, awe-inspiring place, and it is the only world most of us will ever know.

NASA has a unique vantage point for observing the beauty and wonder of Earth and for making sense of it. Looking back from space, astronaut Edgar Mitchell once called Earth “a sparkling blue and white jewel,” and it does dazzle the eye. The planet’s palette of colors and textures and shapes—far more than just blues and whites—are spread across the pages of this book.

We chose these images because they inspire. They tell a story of a 4.5-billion-year-old planet where there is always something new to see. They tell a story of land, wind, water, ice, and air as they can only be viewed from above. They show us that no matter what the human mind can imagine, no matter what the artist can conceive, there are few things more fantastic and inspiring than the world as it already is. The truth of our planet is just as compelling as any fiction.

We hope you enjoy this satellite view of Earth. It is your planet. It is NASA’s mission.

Michael Carlowicz Earth Observatory Managing Editor

The astonishing thing about the Earth... is that it is alive.... Aloft, floating free beneath the moist, gleaming membrane of bright blue sky, is the rising Earth, the only exuberant thing in this part of the cosmos.... It has the organized, self-contained look of a live creature, full of information, marvelously skilled in handling the Sun. —Lewis Thomas, The Lives of a Cell

We shall not cease from exploration, and the end of all our exploring will be to arrive where we started and know the place for the first time. —T.S. Eliot, “Little Gidding”

We shall not cease from exploration, and the end of all our exploring will be to arrive where we started and know the place for the first time. —T.S. Eliot “Little Gidding”

Earth and sky, woods and fields, lakes and rivers, the mountain and the sea, are excellent schoolmasters, and teach some of us more than we can ever learn from books. —John Lubbock, The Use of Life

Earth and sky, woods and fields, lakes and rivers, the mountain and the sea, are excellent schoolmasters, and teach some of us more than we can ever learn from books. —John Lubbock The Use of Life

ice and snow

It seems to me that the natural world is the greatest source of excitement; the greatest source of visual beauty; the greatest source of intellectual interest. It is the greatest source of so much in life that makes life worth living. —David Attenborough

Imagery and data courtesy of:

• NASA Earth Observatory
• U.S. Geological Survey (USGS) and NASA Landsat Program
• International Space Station (ISS) Crew Earth Observations Facility
• LANCE/EOSDIS MODIS Rapid Response Team
• MABEL Science Team
• Level-1 and Atmosphere Archive & Distribution System Distributed Active Archive Center (LAADS DAAC)
• EO-1 Science Team
• Suomi National Polar-orbiting Partnership (Suomi NPP)
• NASA Ocean Biology Processing Group
• NASA/METI/ERSDAC/JAROS/Japan ASTER Science Team

Adapted for the web by Paul Przyborski

About the Authors

Michael Carlowicz is managing editor of the NASA Earth Observatory. He has written about Earth science and geophysics since 1991 for several NASA divisions, the American Geophysical Union, the Woods Hole Oceanographic Institution, and in three popular science books. He is a baseball player and fan, a longtime singer and guitarist, and the proud father of three science and engineering majors.

Kathy Carroll supports the Earth Science Division in the Science Mission Directorate at NASA Headquarters. She previously worked as a manager and organizer at for-profit and non-profit organizations and on political campaigns. She is a diehard baseball and hockey fan, and she volunteers with animal rescue organizations.

Lawrence Friedl directs the Applied Sciences Program in the Earth Science Division of NASA’s Science Mission Directorate. He works to enable innovative and practical uses of data from Earth-observing satellites. He has worked at the U.S. Environmental Protection Agency and as a Space Shuttle flight controller in NASA’s Mission Control Center. He and his wife have three children, and he enjoys ultimate frisbee and hiking.

Stephen Schaeberle is a graphic designer with the Communications Support Services Center at NASA Headquarters. He holds a bachelor of fine arts from the Pratt Institute, and he has received numerous awards and honors for his work and designs. He enjoys boating and fishing on the Chesapeake Bay.

Kevin Ward manages NASA’s Earth Observatory Group, including the Earth Observatory, Visible Earth, NASA Earth Observations (NEO), and EONET. He holds a master’s degree in library and information science and has spent more than 20 years developing Web-accessible resources in support of NASA Earth science communications. He and his wife have a son and a deep love of music.

Acknowledgments

Just a few names end up on the title page of a book, but it takes an entire cast of people to bring it from idea to draft to finished product. The cast for Earth begins with Maxine Aldred, Andrew Cooke, Tun Hla, and Lisa Jirousek, who shepherded the words and images through design and layout. Thanks are also due to Kathryn Hansen, Pola Lem, Rebecca Lindsey, Holli Riebeek, Michon Scott, and Adam Voiland, whose reporting and writing contributions gave this book its depth. Joshua Stevens, Robert Simmon, Jesse Allen, Jeff Schmaltz, Michael Taylor, and Norman Kuring applied their strong visual sense and processing skills to make each image pop with color and texture while remaining scientifically accurate.

We owe a debt to our scientific and outreach colleagues, who keep the satellites running, the sensors sensing, and the data and imagery flowing. Every one of the images in this book is publicly available through the Internet, truly making science accessible to every citizen. The Landsat teams at the U.S. Geological Survey and NASA, the LANCE/EOSDIS MODIS Rapid Response Team, and the NASA Earth Observatory deserve extra gratitude for making our planet visible to the scientist and the layman every day.

NOTIFICATIONS

Natural satellites.

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A satellite is anything that orbits around a larger object. A natural satellite is any celestial body in space that orbits around a larger body. Moons are called natural satellites because they orbit planets.

Satellites that are made by people and launched into orbit using rockets are called artificial satellites. There are thousands of artificial satellites orbiting the Earth.

Any large object that orbits around a planet is called a moon (small ‘m’). The Earth has one moon called the Moon (capital ‘M’). The Moon takes 27.3 days to orbit the Earth once, moving at an orbital speed of 1 km/s.

Find out more about our Moon here .

Moons around other planets

Galileo was the first person to discover that other planets can have moons. He saw that Jupiter had four moons with his newly invented telescope in 1610 AD. At first, he thought they were stars, but he noticed that, each night, the four points of light appeared to change positions slightly. He realised they were actually moons orbiting around Jupiter. Another astronomer of the time, Simon Marius, named them Io, Europa, Ganymede and Callisto after the lovers of Zeus, the ancient Greek mythological King of the Gods and Men. We now know that Jupiter has at least 64 moons.

All except two of the planets (Venus and Mercury) in our Solar System have natural satellites called moons.

Other natural satellites in our Solar System

Planets, asteroids and comets orbit around stars such as our Sun and so can also be thought of as natural satellites. Our Solar System has eight official planets as well as millions of minor planets, asteroids, comets and other objects orbiting around the Sun. All of these can be thought of as natural satellites.

All of these natural satellites are held in orbit by the attraction of gravity between the satellite and the object it is orbiting.

For elliptical orbits, perihelion means closest orbital approach to the Sun, and aphelion means furthest orbital distance from the Sun.

Earth’s natural satellite: the Moon

The Moon orbits the Earth once every 27.3 days. This time period is called the orbital period or sidereal period. However, the time from one full moon to the next is 29.5 days (called the synodic period). This extra time is because of the change in angle as the Earth revolves around the Sun.

The Moon appears to move across the sky from east to west, in the same direction as the Sun moves. However, this motion is apparent and not true. The Moon is in fact orbiting the Earth in a west to east direction. The reason that it appears to rise in the east and set in the west is because of the Earth’s very fast axial rotation. The Earth rotates once each day, and the Moon orbits the Earth once every 27.3 days. This means that the Moon’s true orbital motion around the Earth can be seen only indirectly. The distance moved by the Moon in 1 day can be observed by comparing its position in the sky at one time with its new position exactly 24 hours later.

Nature of science

Galileo was able to view only four of Jupiter’s 64 moons. He was limited by the quality and power of the telescopes available to him at the time. Nowadays with far more powerful and high-quality telescopes, we can see further and with more detail. Gains in scientific knowledge and understanding are often connected to technological advances in the equipment used to aid our powers of observation.

Useful links

Learn more about the Moon from NASA.

Visit the Stardome Observatory and Planetarium website for resources and activities about comets.

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Satellite Imagery: Strengths and Weaknesses Essay

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Introduction

Visible satellite imagery, infrared satellite imagery, vapor satellite imagery, fog satellite imagery.

The invention of the satellite was vital to exploring the planet from above by revealing features that had not been seen. The technology has been used to capture images of landscapes and other fascinating features on the earth. Weather forecasters and flight directors rely on this technology to give reliable information to the public and the cabin crew. Many astronauts and space researchers depend on satellite imagery as a weather forecasting system to schedule their space missions. Various types of technology present significant opportunities as well as drawbacks that impact their overall applications.

Visible satellite imagery uses sunlight to record images, making it work well during the day. This technology possesses the ability to display the difference between underlying fog and stratus, which other imaging technologies like Infrared imagery may not capture, provided such areas are not blocked from view by higher clouds (Felegari et al., 2021). Contrary to the advantages mentioned above, the University of Wisconsin Department of Atmospheric and Oceanic Sciences indicates that visible imagery is only useful during the daylight hours, making it difficult to distinguish low clouds from high clouds since all clouds reflect a similar amount of light (Felegari et al., 2021). In addition, it is challenging to distinguish snow from clouds, which may lead to unreliable data.

Infrared imagery uses emitted wavelengths to record images, which can be done during the day or night. The University of Wisconsin, Department of Atmospheric and Oceanic Sciences, states that this technology has the ability to distinguish higher clouds from lower ones. Furthermore, it makes it possible to observe storms at night using this imagery, in addition to differentiating clouds from snow cover (Zou et al., 2021). It is unreliable for detecting low clouds at night because the temperature emitted by underlying clouds and fog is somewhat the same as in surrounding areas

This technology is often applied to detect the presence of vapor above twenty thousand feet in the atmosphere. It is mainly used to forecast and analyze the paths in addition to higher level motion of moisture when multiple such images are looped together (Gadamsetty et al., 2022). This technology is used to give pilot briefings and directions because it detects jet streams and high headwinds. It is vital for identifying mountain wave turbulence on airways even under clear visibility. Despite being used in flight control, Vapor Imagery does not show the presence of low clouds or water vapor content below the effective layer. Similarly, it is unable to give the measure of atmospheric vapor below the effective layer.

Finally, fog satellite imagery, like visible images, is majorly useful during the day only because if a fog lies between the middle and upper clouds, it becomes difficult to detect due to limited grey scale variability. In comparison to visible imagery, this technology displays smoother images. Therefore its accuracy can be hampered by contrasting temperatures between cloud top and the surrounding sea and when the land surface is small.

Satellite technology is vital in day-to-day global operations; weather forecasting, air travel, and space travel all rely on the data acquired by this technology. This invention has expanded human knowledge about the planet and the solar system by revealing secret features on earth and remarkable images of the galaxy. The four types of Satellite imagery we have discussed have advantages and disadvantages; however, the accuracy and the reliability of the data generated by each system depend on the time of day it is appropriate to be used. There is some visible imagery that is more reliable during daylight, whereas others, including infrared and water vapor, can be reliable both at night and during sunlight.

Felegari, S., Sharifi, A., Moravej, K., Amin, M., Golchin, A., Muzirafuti, A., Tariq, A. & Zhao, N. (2021). Integration of Sentinel 1 and Sentinel 2 satellite images for crop mapping . Applied Sciences , 11 (21), 10104. Web.

Gadamsetty, S., Ch, R., Ch, A., Iwendi, C., & Gadekallu, T. R. (2022). Hash-based deep learning approach for remote sensing satellite imagery detection . Water , 14 (5), 707. Web.

Zou, Y., Zhang, L., Liu, C., Wang, B., Hu, Y., & Chen, Q. (2021). Super-resolution reconstruction of infrared images based on a convolutional neural network with skip connections . Optics and Lasers in Engineering , 146 , 106717. Web.

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IvyPanda. (2024, January 29). Satellite Imagery: Strengths and Weaknesses. https://ivypanda.com/essays/satellite-imagery-strengths-and-weaknesses/

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Earth Observations from Space: The First 50 Years of Scientific Achievements (2008)

Chapter: 12 conclusions.

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

12 Conclusions Just as the invention of the mirror allowed humans to see their coverage than obtained during the intensive field expeditions own image with clarity for the first time, Earth observations of the IGY from the comfort of their desktops. from space have allowed humans to see themselves for the The advent of satellites revolutionized the Earth sci- first time living on and altering a dynamic planet. ences. They provided the first complete global record of biological, physical, and chemical parameters such as cloud THE EMERGENCE OF INTEGRATED cover, winds, and ice cover. They provided consistency of EARTH SYSTEM SCIENCE coverage not available with ground measurements. Time series data revealed large-scale processes and features that During the International Geophysical Year (IGY) of could not have been discovered by other ways. Prior to the 1957-1958, 67 nations cooperated in an unprecedented effort availability of satellite-based observations, scientists seek- to study the Earth. In an age otherwise characterized by ing global perspectives from largely ground-based observa- Cold War tensions, the noted geophysicist Sydney Chapman tions were required to develop international collaborations (1888-1972) referred to the IGY as “the common study of and launch large-scale field campaigns. Piecing together our planet by all nations for the benefit of all.” This global data points required interpolation and extrapolation to fill effort laid the foundation for the integration of Earth sci- data gaps, particularly for remote locations. In addition, ences and demanded widespread simultaneous observations. large-scale sampling efforts involved extensive logistics It involved large teams of observers, many of whom were and advance planning, which prohibited frequent repetition. deployed to the ends of Earth—in polar regions, on high Because the rate of change of many parameters of interest mountaintops, and at sea—to study meteorology, oceanog- is much greater than the rate at which global maps could be raphy, glaciology, ionospheric physics, aurora and airglow, produced in the presatellite era, it was impossible to observe seismology, gravity, geomagnetism, solar radiation, and the full dynamics of the system. cosmic rays. Even in 1957 it was recognized that satellite Therefore, the unique and revolutionary vantage point data would bring observations of Earth that no amount of from space provides scientists with global images and maps ground-based observations could achieve. of parameters of interest unmatched by any ground-based Hundreds of sounding rockets were launched into the observing technology in terms of frequency and coverage. upper atmosphere and near space during the IGY, and the Because satellites collect data continuously and allow for “space age” officially began with geophysical satellites, daily (or at least monthly averaged) global images, changes although still in their infancy, playing an important role can be observed at the relevant temporal and spatial scale (Chapter 2). During the IGY the Soviet Union launched the required to detect Earth system processes. The full ­dynamics world’s first satellite, Sputnik, in October 1957. The United of the system have only been observed or characterized States launched its first satellite, Explorer 1, shortly there­after since the advent of satellite observations and have allowed in January 1958. Over the course of the next five decades, the the study of previously inaccessible phenomena such as United States and its international partners have launched an stratospheric ozone creation and depletion, the transport of array of satellites that fundamentally altered our understand- air pollution across entire ocean basins from China to the ing of the planet. A half-century later, Earth scientists can continental United States (Chapter 5), global energy fluxes acquire global satellite data with orders of magnitude greater (Chapter 4), ice sheet flow (Chapter 7), global primary pro- 98 

CONCLUSIONS 99 ductivity (Chapter 9), ocean currents and mesoscale features summer ice over the past decades (Chapter 7). Satellite (Chapter 8), and global maps of winds (Chapter 8). Prior to observations have become available and matured as scientific the satellite era, even if it was possible to compose a global data at a time when they are critically important in helping picture from individual surface observations (e.g., through society manage planetary-scale resources and environmental the World Weather Watch, established in 1963), the coverage challenges. Although many scientific challenges remain, it is and density of the network and lack of vertical resolution undeniable that satellite observations have allowed scientists left much to be desired. Other geophysical and biological to improve the ability to monitor and predict changes in the phenomena were sampled much less frequently, often as a Earth system and manage life on Earth (NRC 2007a). partial “snapshot” of an otherwise dynamic set of interacting It is widely known that satellite data, particularly from Earth processes. the southern hemisphere, have contributed to improvements Discovery of the variability in the velocity of ice sheet in weather prediction, resulting in protection of human lives flow is another example of how the dynamics of the sys- and infrastructure (Chapter 3). Since the availability of sat- tem went undetected until reliable and repeated satellite ellite images, no tropical cyclone has gone undetected, and observations became available (Chapter 7). This discovery the advance warning allows crucial time to prepare. In fact, revolutionized the study of ice sheet flow and yielded an the advent of satellites has been heralded as unquestionably important realization: sea-level change due to freshwater “the greatest single advancement in observing tools for input from the continental ice sheets was not a function of tropical meteorology” (Sheets 1990). Furthermore, because the balance between ice sheet melting and precipitation at satellite data give access to the largely undersampled ocean, higher elevation, but a function of the flow dynamics. The hurricane track forecasts have improved dramatically, help- increasing velocity of continental ice flow into the ocean in ing save lives and property every year (Considine et al. response to climate change and the collapse of the Larsen B 2004). Other aspects of human welfare have and will also Ice Shelf emphasized the sensitivity of ice sheet dynamics benefit from satellite observations. For example, it is also to a changing climate. unlikely that a famine early warning system would be avail- Satellite sensors provide a panoptic viewpoint, yet his- able to assist in planning aid distribution without the ability torically they suffered from poor resolution and calibration to observe vegetation cover and the availability of water problems. On the other hand, ground-based instruments, resources from space (Chapter 10). Given the projected although more precise and better calibrated, are limited to climate change and associated sea-level rise, having global their particular locales, and problems arise since they must be satellite coverage available in the future will serve crucial coordinated and intercalibrated with other ground stations. societal needs unmet by any other observing system. As satellite sensors and data processing have become more sophisticated, equaling or surpassing those for ground-based Conclusion 1: The daily synoptic global view of measurements, scientists have obtained not only images but Earth, uniquely available from satellite observations, has also quantitative global measurements of unprecedented revolutionized Earth studies and ushered in a new era of precision. Intercalibration proved particularly challenging in multidisciplinary Earth sciences, with an emphasis on putting together global maps of marine primary productiv- dynamics at all accessible spatial and temporal scales, ity from shipboard measurements (Chapter 9). Estimating even in remote areas. This new capability plays a criti- marine primary productivity requires sample manipulation cally important role in helping society manage planetary- and measurements of 14C uptake rates at each location, scale resources and environmental challenges. which are sensitive to variations in sampling techniques and methods. Although global marine primary productivity INTEGRATED GLOBAL VIEW OF THE CARBON CYCLE estimates had been attempted before the satellites era, they AND CLIMATE SYSTEM were flawed because of intercalibration issues. More impor- tantly, because it takes years to obtain global coverage of The global view of Earth from satellites has imparted ground-based marine primary productivity measurements, the understanding that everything is connected—land, ocean, satellites allowed for the first time observation of global and atmosphere. Interdisciplinary teams of ­researchers have marine primary productivity on a monthly and annual basis explored these connections to better understand the Earth and detection of decadal-scale trends. as a system beyond the sum of its elements. The concept Satellite observations also provide access to otherwise of studying the Earth as an integrated system at a national virtually inaccessible regions, such as polar regions, the upper level was led by the National Aeronautics and Space atmosphere, and the open oceans. Quantitative assessment Administration (NASA), inspired by NASA’s “Ride report” and monitoring of the sea ice extent in the Arctic has only (NASA 1987), and intended as the U.S. component to the been possible since routine satellite observations became International ­Geosphere-Biosphere Program. Consequently, available. Without satellite images, it is unlikely that trends in NASA launched its mission to planet Earth to study the decreasing Arctic summer sea ice would have been detected Earth’s geosphere and biosphere as an integrated system as readily, demonstrating univocally the drastic decline in instead of discrete but interrelated components (CRS 1990). 

100 EARTH OBSERVATIONS FROM SPACE: THE FIRST 50 YEARS OF SCIENTIFIC ACHIEVEMENTS Other nations have also made significant contributions to which in turn affects the amount of carbon dioxide (CO2) the ­capacity to observe Earth from space. This multinational uptake (Chapter 9); and water vapor is important as a investment has enabled much international collaboration greenhouse gas and in heat exchange processes between the among satellite projects. ocean, land, and atmosphere (Chapters 3, 4, 8, and 9). Due A prime example of an interdisciplinary research to water’s relatively high specific heat capacity and its large- endeavor is the study of the global carbon cycle, which scale circulation, the ocean plays a central role in storing and employs a wide range of research approaches such as ground transporting Earth’s heat content (Chapter 8). In fact, more and satellite observations, modeling studies, and laboratory than 80 percent of Earth’s heat is stored in the ocean. Improv- experiments. The well-known Keeling curve was obtained ing our understanding of ocean circulations and consequently from in situ observations and revealed atmosphere-biosphere the transport of heat is a major challenge to more accurate interactions, as well as the long-term trend of increasing climate models and predictions. Lastly, the above-mentioned atmospheric carbon dioxide (Keeling et al. 1976). These find- advances in understanding the global carbon cycle further the ings launched major efforts in understanding the role of the ability to predict future atmospheric CO2 levels. terrestrial and oceanic biosphere in carbon uptake through The long-term observations obtained during the past 50 photosynthesis and the impact of increased carbon dioxide years of Earth science from space combined with advances levels on global climate. However, primary productivity is in data assimilation, computer models, and ground-based controlled by geophysical processes; thus, understanding the process studies brought climate scientists to the point at interconnections, such as the effect of a changing climate which they could begin to project how climate change will and hydrologic cycle on the global biosphere and vice versa, affect weather and natural resources at the regional level, required observations at a global scale of land-cover changes the scale at which the information is of greatest societal (from Landsat and AVHRR [Advanced Very High Resolu- relevance (NRC 2001a). tion Radiometer]; see Chapter 11), biomass estimates and This comes at a time when improved understanding of primary productivity (AVHRR, CZCS [Coastal Zone Color the climate system is central to the viability of our economy, Scanner], SeaWiFS [Sea-viewing Wide Field-of-view Sen- as seasonal-to-interannual climate fluctuations strongly sor], and MODIS [Moderate Resolution Imaging Spectrora- influence agriculture, the energy sector, and water resources diometer]; see Chapters 9 and 10), changes in the hydrologic (CCSP 2003). However, important scientific challenges—for cycle (Landsat, AVHRR, MODIS, and Topography Experi- example, cloud-water feedback in climate models—must be ment (TOPEX)/Poseidon; see Chapters 6 and 7) and climate conquered with the aid of continuous satellite data before (AVHRR, MODIS, and SeaWiFS). Once the data were avail- the appropriate seasonal-to-interannual climate information able, major scientific advances came from assimilating them can be made readily available at the appropriate scale (NRC into three-­dimensional coupled modeling of the atmosphere, 2007a). The Earth science community has built over the past land, ocean, and cryosphere (Fung 1986, Heiman and Keel- decades the capacity to incorporate all the pieces into an ing 1986, Fung et al. 1987, Keeling et al. 1989). integrated systems perspective, thanks to ever more sophis- Equally interdisciplinary in nature is climate change ticated models. As the community is now poised to make research. In fact, many of the accomplishments highlighted major advances in climate science and predicting climate in this report have contributed to the improved understand- changes at various scales, the ability to provide sustained ing of the climate system and laid the groundwork modeling multidecadal global measurements is crucial (NRC 1999, for projecting climate change. One notable example is the 2001b, 2007a). long-term observations of Earth’s radiation budget, which The ability to observe and predict El Niño/La Niña revealed the role of the ocean and atmosphere in transporting conditions in advance of their full manifestation based on heat and the role of aerosols from the volcanic eruption of satellite and in situ data illustrates the significant break- Mount Pinatubo in cooling the climate (Chapter 4). With the through climate scientists have made in providing impor- understanding of the importance of aerosols to the climate tant regional climate information to resource managers system comes the need to observe continuously both natural (Box 12.1, Figure 12.1). and anthropogenic sources of aerosols (Chapter 4). Satellite As many accomplishments have shown, the length and observations have also been central in revealing the role of continuity of a given data record often yield additional sci- important gases, such as water vapor and ozone, in the cli- entific benefits beyond the initial research results of the mis- mate system (Chapters 4 and 5). sion and beyond the monitoring implications for operational Long-term observations of water in each phase are agencies. For example, the effect of aerosols from a volcanic central to understanding the climate system: sea ice contrib- eruption (Mount Pinatubo) on the global climate would utes to Earth’s albedo and its decrease not only indicates a have gone undetected without the continuous observations warmer climate but is also a positive feedback (Chapter 7); of the Earth Radiation Budget Experiment (ERBE, Chapter melting of continental ice sheets contributes to sea-level 4). Thus, maintaining well-calibrated long-term data sets is rise (Chapter 7); the availability of liquid water is important likely to yield important scientific advances in understanding in controlling the productivity of the terrestrial ecosystem, the Earth system, in addition to contributing to societal appli- 

CONCLUSIONS 101 cations. The importance of stable, accurate, intercalibrated, to measure the geopotential and mean sea level to determine long-term climate data records is universally recognized, and the general circulation of the oceans and resolve the spatial strategies on how to collect and maintain such data streams variations of the gravity field as a goal for geophysics and have been provided in many previous reports (NRC 1985, physical oceanography. NASA responded to this challenge 2000, 2001b, 2003, 2004). Important elements to successful by launching three satellites within 9 years following the long-term climate data from satellites include a long-term Williamstown conference, with Seasat—the third and most strategy to guarantee that follow-on missions overlap to advanced satellite—providing accurate ocean elevation allow for cross-calibrations, leadership in data stewardship with a precision to tens of centimeters. For the first time the and management, and strong interagency collaborations. bathymetry of the ocean floor could be observed from space, Follow-on missions maximize the return on previously revealing the large mid-Atlantic ridges and trenches (Chap- made investments in technology development, including sen- ter 11). As the precision of altimetry data further increased sors and data analysis tools. Missions designed for process the importance of eddies in the mixing of the open ocean was studies of initially short durations may provide significant discovered (Chapter 8). scientific value by continuing a given data record in the It is common for any given satellite or instrument in context of global change research. The value of a continuous space to supply data that may be used in multiple fields of data record increases significantly through the development Earth science by design or serendipitously (see Table A.1). of uninterrupted follow-on missions, particularly if careful Although Landsat was designed to observe changes on land, cross-calibrations between subsequent generations of satel- including the terrestrial ecosystem, assembling the approxi- lite sensors are undertaken (NRC 2004). The long-term data mately 5,000 individual images for a global time series records from Landsat and AVHRR exemplify the scientific proved to be too computationally intensive. Instead, it was value of such carefully maintained data streams (Chapters 9 AVHRR data—designed to monitor the atmosphere—that and 10). turned out to be invaluable to producing global terrestrial primary productivity estimates. Due to careful intercalibra- Conclusion 2: To assess global change quantitatively, tions between the different sensors, the AVHRR data record synoptic data sets with long time series are required. The now extends over 20 years (Chapter 8) and has allowed value of the data increases significantly with seamless and the detection of trends in terrestrial primary productivity intercalibrated time series (NRC 2004), which highlight (Chapter 9). In fact, data from AVHRR have also been used the benefits of follow-on missions. Further, as these time in many other fields to study processes such as snow cover, series lengthen, historical data sets often increase in sci- sea surface temperature, cloud optical properties, and global entific and societal value. land-cover change (Chapters 6, 8, and 10). The design of MODIS illustrates the potential for using a single instrument to serve many applications. Its spectral MAXIMIZING THE RETURN ON INVESTMENT IN bands were designed to serve a diversity of user commu- EARTH OBSERVATIONS FROM SPACE nities in the Earth sciences, allowing observations of the As scientists have gained experience in studying Earth following parameters: land, cloud, and aerosol properties; through satellite observations, they have defined new tech- ocean color and marine biogeochemistry; atmospheric water nology needs, helped drive technology development to vapor; surface and cloud temperature; cloud properties; provide more quantitative and accurate measurements, and cirrus cloud water vapor; atmospheric temperature; ozone; advanced more sophisticated methods to interpret satellite and cloud top altitude. It has led to scientific breakthroughs data (Chapter 2). Many scientific accomplishments have such as discovery of the brown clouds (Chapter 4), measur- resulted from rapid satellite technology development that ing marine primary productivity annually (Chapter 9), and responded to scientific needs and provided capabilities that observation of optical depth and effective particle radius in enabled major advances in the Earth sciences. The value of low clouds (Chapter 4). Because of the potential to design satellite observations from space grows dramatically as new, missions with spectral bands that can serve many different more accurate instruments are developed. Initially, satel- scientific user communities, creating follow-on missions lites provided a means for acquiring pictures. Now, satellite that continue measurements—and thus ensure the long- image acquisition and interpretation provide quantitative term climatic data records discussed above—does not have geo­physical or biological variables by transforming measure- to come at an increased cost or at the cost of research and ments of reflected or emitted electromagnetic radiation into development missions. desired parameters. For many applications such as ocean In addition, the measurement of a given variable, in and land topography, ice sheet dynamics, and concentra- some cases from multiple sensors, often contributes to tions of atmospheric gases, observations are scientifically several fields of Earth science. For example, few scientific valuable if they can be made with great accuracy, which has accomplishments are as “transformative” as the advances in driven technology evolution. For example, the Williamstown space geodesy over the past five decades (Chapter 11). This report (NASA 1970) outlines the need for satellite sensors breakthrough has not only transformed the field of geodesy 

102 EARTH OBSERVATIONS FROM SPACE: THE FIRST 50 YEARS OF SCIENTIFIC ACHIEVEMENTS BOX 12.1 El Niño-Southern Oscillation El Niño is a condition that has been known for well over a century. In some years waters off the west coast of South America would become warmer than usual, and the fish populations normally found there would disappear, bringing hardship to fishermen in the region. It occurs periodically around Christmastime and thus was named “El Niño”—the Spanish term referring to the Christ Child. Much of the groundwork for understanding and describing the El Niño-Southern Oscillation (ENSO) as a coupled atmosphere-ocean phenomenon was laid in the 1970s and 1980s and based on in situ data and modeling studies (e.g., Rowntree 1972, Wyrtki 1975, Rasmusson and Carpenter 1982, Zebiak 1982, Shukla and Wallace 1983, Cane 1984). However, satellite data confirmed observations and model efforts and revealed the global impact of ENSO (Friedler 1984). The improved understanding of the atmosphere-ocean connection has improved the ability to predict ENSO conditions and has advanced our understanding of the teleconnections and impacts on the marine and ter- restrial biosphere (Barber and Chavez 1983). In normal years winds blow from east to west, causing warm surface waters to “pile up” in the western tropical Pacific. During an El Niño, the winds relax and the warm surface waters flow back toward the eastern Pacific. Wind- driven upwellings do not reach deep enough to bring nutrients from below the thermocline. Without the supply of nutrients, phytoplankton do not thrive and this creates a chain reaction in the marine ecosystem. The major El Niño event of 1982 revealed its impacts not only on the ocean but also on global weather patterns, which invigorated re- search efforts to improve ENSO predictions. Because ENSO events are accompanied typically by drought conditions in Indonesia and Australia and heavier-than-normal rainfall in South America, their effects can be seen in virtually every form of Earth observations from space. By piecing together the different observations (sea surface temperature [SST], winds, sea surface height, biological productivity, rainfall, and land cover), scientists are working to develop theories to explain what triggers an El Niño and to predict consequences once an El Niño has developed. Satellite observations of SST and winds combined with in situ data are also used to predict El Niño events up to a year in advance. Figure 12.1 illustrates­ how the physical and biological properties of the Pacific are related during an El Niño and the opposite, La Niña, condition. FIGURE 12.1  These images of the Pacific Ocean show conditions during an El Niño (1997) and La Niña (1998). The upper images were produced using sea surface height measurements made by the U.S.-French TOPEX/Poseidon satellite. They show variations in sea surface height relative to normal conditions as an indicator of the amount of heat stored in the ocean. The two lower images show variability in chlorophyll concentration relative to normal levels as a measure of phytoplankton biomass. These were produced using data from SeaWiFS. In 1997 the warm surface water in the eastern Pacific (shown in white in the upper figure) was 14 to 32 cm (6 to 13 in.) higher than normal and about 10 cm (4 in.) above normal in the red areas. The same waters were abnormally low in chlorophyll (shown in blue in the lower image) because the supply of nutrients from upwelling was greatly reduced. This El Niño condition results in the well-known absence of fish off the west coast of South America. The images for 1998 show the low sea level or a cold pool of water (shown in purple in the upper image) during the La Niña phase. The lower figure shows higher- than-average chlorophyll (yellow) associated with this cold pool. During La Niña, nutrients were upwelled into the cold pool, resulting in an extensive phytoplankton bloom at the equator that lasted for several months. SOURCE: NASA Jet Propulsion Laboratory (top row); provided by J. Campbell and based on data from SeaWiFS Project, NASA Goddard Space Flight Center, and GeoEye (bottom row). 

CONCLUSIONS 103 a b Mapped – 1997 Mapped – 1998 c d 12-1 a,b,c,d 

104 EARTH OBSERVATIONS FROM SPACE: THE FIRST 50 YEARS OF SCIENTIFIC ACHIEVEMENTS but also provided vital information for studying global sea- increasingly important in pushing satellite sensors to provide level change, earthquakes, and volcanoes. Furthermore, more quantitative and accurate measurements. Ocean buoys Earth scientists from all disciplines rely on an International and drifters as well as shipboard observations have been Earth Reference Frame from which geographical positions used extensively to validate sea surface temperature, ocean can be accurately described relative to the geocenter, in three- color, and wind observations from satellites (Chapter 8). In dimensional Cartesian coordinates to centimeter accuracy or addition, as satellite data have become more quantitative and better—a 2 to 3 orders of magnitude improvement compared more readily used by the broader research community, they to 50 years ago. have contributed to field campaigns and altered the scientific Measured by AVHRR and SAGE (Stratospheric ­Aerosol endeavor. For example, ground-based campaigns are more and Gas Experiment), aerosols represent a geophysical effectively planned and guided because of the information variable important to Earth’s radiation budget, air ­ quality made available from satellite observations. forecasts, cloud formation affecting weather forecasts, Just as the synergy between satellite and ground-based and hydrologic applications (Chapter 4). Thus, a scientific observations yields new insights, so does the combination accomplishment in one field can lead to major advances in of satellite observations from different instruments. Thus, other fields and drive interdisciplinary research efforts. The to capitalize fully on some investments in satellite sensors, advances in understanding and predicting El Niño-Southern simultaneous measurements are necessary. The recent analy- Oscillation (ENSO) conditions exemplify the advantage of sis of the merged altimetry data set from TOPEX/Poseidon studying the Earth as an integrated system and the benefit of and the European Remote Sensing Satellite (ERS) revealed combining in situ and satellite observations with modeling the prevalence of westward-propagating eddies not seen from studies. individual sensors (Chapter 8). This discovery would not have been possible without merging the two data sets from Conclusion 3: The scientific advances resulting from the individual sensors. Earth observations from space illustrate the successful synergy between science and technology. The scientific Conclusion 4: Satellite observations often reveal and commercial value of satellite observations from known phenomena and processes to be more complex space and their potential to benefit society often increase than previously understood. This brings to the fore the d ­ ramatically as instruments become more accurate. indisputable benefits of multiple synergistic observations, including orbital, suborbital, and in situ measurements, The observational vantage point from space added a new linked with the best models available. appreciation for the complexity of many previously known Earth science processes. Because of the problem of spatial The greatest benefit of Earth observations from space and temporal undersampling by ground-based observing is gained when data are integrated into state-of-the-art tools, composing a synoptic view required interpolation m ­ odels, combined with ground-based observation net- across data gaps. Consequently, more complex features work and process studies, and analyzed with sophisticated were averaged out through the interpolation process and methods. Model development has aided in developing an not revealed until satellites observed these features directly. inter­disciplinary thinking in the Earth sciences. Building Similarly, the frequency of synoptic views available from sophisticated models and data analysis tools often involves daily satellite overflights made an unprecedented temporal long lead times and requires training of a skilled workforce. resolution available. As altimetry measurements became Consequently, the major scientific breakthrough might accurate to the centimeter scale, they revealed how highly f ­ ollow years after the satellite data have first become avail- time dependent and essentially turbulent the ocean was, able. To capitalize fully on the investment, satellite data also which is in contrast to the presatellite view that the ocean was require careful calibration (NRC 2004). In addition, building primarily in steady state with slowly changing, large-scale long-term data records for climate research requires cross- circulation (Chapter 8). This resulted in a ­paradigm shift with and intercalibration between various sensors and follow-on implications for climate change research that have yet to be missions, data processing and archiving, and maintenance of fully understood (Wunsch 2007). the metadata (NRC 2004). In the case of many scientific accomplishments, signifi- To develop the aforementioned infrastructure and data cant results are not solely based on satellite data but include assimilation and analysis tools, scientists need to be trained in situ data and model components. In fact, the value of in using and analyzing satellite data. Thus, investment in space-based observations increases with well-coordinated training and supporting a remote sensing community is ground-based observations, suborbital observations, and/or important to guaranteeing scientific advances from satellite cross-calibration among satellites with complementary instru- data (NRC 2007a). Attracting young scientists to the field of ments. Ground-based observations also provide an important remote sensing is made easier by the prospect of stability in “surface validation” for satellite data and are used to calibrate the satellite data supply. In contrast, data gaps may result in spaceborne instruments. Such surface validations become the loss of a highly specialized workforce (NRC 2007a). The 

CONCLUSIONS 105 full benefit of satellite data is only realized when a robust OPPORTUNITIES FOR THE FUTURE OF scientific community is trained to use the data to address EARTH OBSERVATIONS FROM SPACE fundamental and applied research questions. Fifty years from now a report similar to this one is The Landsat story, described in numerous accounts (e.g., likely to describe many more astounding discoveries about NRC 2002), is a case in point: wholesale commercialization the Earth system, if the commitment to satellite observations of the data led to a precipitous drop in their use for science from space is sustained. Although this report provides an and commercial applications, which recovered upon return extensive sampling of important accomplishments enabled to the earlier policy that made data access affordable. Only by Earth satellite data, many scientific questions and societal when academic, government, and commercial scientists challenges remain unresolved, including improving 10-day are given liberal access to data and a sufficient number are weather forecasts, more accurately forecasting hurricane trained in the effective use of these data will the analysis intensity, increasing resolution of earthquake fault systems tools mature to the benefit of all parties. Similarly, obtain- and volcanoes to detect precursors of events, mitigating ing the maximum benefit from weather satellites required a climate change impacts, and protecting natural resources decade-long process of improving methods of radiance data (NRC 2007a). assimilation (Lord 2006; see Chapter 3). Because the critical infrastructure to make the best use of satellite data takes decades to build and is now in place, the Conclusion 5: The full benefits of satellite observa- scientific community is poised to make significant ­progress tions of Earth are realized only when the essential infra- toward understanding and predicting the complexity of the structure, such as models, computing facilities, ground Earth system. However, building a predictive capability relies networks, and trained personnel, is in place. strongly on the availability of seamlessly intercalibrated long-term data records, which can only be maintained if NASA’s open and free data policy has created a world- subsequent generations of satellite sensors overlap with wide linked community of Earth scientists. This open-access their predecessors. Unfortunately, the current capability to policy encourages use of the data for scientific purposes and observe Earth from space is jeopardized by delays in and lack maximizes the potential societal benefits of the observations. of funding for many critical satellite missions (NRC 2007a). The long list of accomplishments is unlikely to have mate- Because important climate data records and important Earth- rialized without this open data policy that encouraged the observing missions are at risk of suffering detrimental data growth of the field (NRC 2004). As previously mentioned, gaps or of being cut altogether, the committee strongly agrees when the Landsat program was privatized during the late with the following recommendation by the decadal survey 1980s and early 1990s, the data became so costly that it (NRC 2007a): severely hampered the research program (Malakoff 2000), illustrating the importance of maintaining free or affordable The U.S. government, working in concert with the data streams. private sector, academe, the public, and its international Open access also increases the societal benefits of the partners, should renew its investment in Earth-observing data by allowing nations without the observational capa- systems and restore its leadership in Earth science and bilities of the developed world to gain access to important applications. environmental observations. The Famine Early Warning System Network, although developed by a U.S. agency, is an To sustain the rate of scientific discovery and advances, example of such an application that aids developing nations committing to the maintenance of long-term observing in resource management without having to first build the capacities and to innovation in observing technology is ground-based observational capabilities. Consequently, data equally important. Because past observations taught scien- sharing among agencies and other countries leads to more tists that the Earth is a highly dynamic system and not as than the sum of its parts, particularly if nations with Earth- predictable as initially assumed, long-term observations are orbiting satellites collaborate on an international strategy required if humans wish to understand and predict future regarding the important satellite missions and data needs to changes. Future advances will be associated with tremendous observe the Earth system (NRC 2007a). societal benefits, given the current challenges presented, for example, by climate change and loss of biodiversity. One can Conclusion 6: Providing full and open access to global envision the availability of regional annual climate predic- data to an international audience more fully capitalizes tions to assist in water resource management, an infectious on the investment in satellite technology and creates a disease early warning system, operational use of air pollution more interdisciplinary and integrated Earth science com- maps, and improved ability to foresee volcanic eruptions or munity. International data sharing and collaborations on earthquakes (NRC 2001a, 2007a). satellite missions lessen the burden on individual nations The committee strongly agrees with the following lines to maintain Earth observational capacities. from the interim report of the decadal survey (NRC 2005): 

106 EARTH OBSERVATIONS FROM SPACE: THE FIRST 50 YEARS OF SCIENTIFIC ACHIEVEMENTS Understanding the complex, changing planet on Conclusion 7: Over the past 50 years, space observa- which we live, how it supports life, and how human tions of the Earth have accelerated the cross-disciplinary activities affect its ability to do so in the future is one of integration of analysis, interpretation, and, ultimately, the greatest intellectual challenges facing humanity. It is our understanding of the dynamic processes that govern also one of the most important challenges for society as it the planet. Given this momentum, the next decades will seeks to achieve prosperity, health, and sustainability. bring more remarkable discoveries and the capability to predict Earth processes, critical to protect human lives If the nation’s commitment to continue Earth observa- and property. However, the nation’s commitment to tions from space is renewed, we have seen just the beginning Earth satellite missions must be renewed to realize the of an era of Earth observations from space, and a report in 50 potential of this fertile area of science. years will be able to highlight many more valuable scientific achievements and discoveries. 

Over the past 50 years, thousands of satellites have been sent into space on missions to collect data about the Earth. Today, the ability to forecast weather, climate, and natural hazards depends critically on these satellite-based observations. At the request of the National Aeronautics and Space Administration, the National Research Council convened a committee to examine the scientific accomplishments that have resulted from space-based observations. This book describes how the ability to view the entire globe at once, uniquely available from satellite observations, has revolutionized Earth studies and ushered in a new era of multidisciplinary Earth sciences. In particular, the ability to gather satellite images frequently enough to create "movies" of the changing planet is improving the understanding of Earth's dynamic processes and helping society to manage limited resources and environmental challenges. The book concludes that continued Earth observations from space will be required to address scientific and societal challenges of the future.

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satellite communication

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satellite communication , in telecommunications , the use of artificial satellites to provide communication links between various points on Earth . Satellite communications play a vital role in the global telecommunications system. Approximately 2,000 artificial satellites orbiting Earth relay analog and digital signals carrying voice, video, and data to and from one or many locations worldwide.

Satellite communication has two main components: the ground segment, which consists of fixed or mobile transmission, reception, and ancillary equipment, and the space segment, which primarily is the satellite itself. A typical satellite link involves the transmission or uplinking of a signal from an Earth station to a satellite. The satellite then receives and amplifies the signal and retransmits it back to Earth, where it is received and reamplified by Earth stations and terminals. Satellite receivers on the ground include direct-to-home (DTH) satellite equipment, mobile reception equipment in aircraft, satellite telephones, and handheld devices.

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Essay on Space Exploration

• Updated on  
• Jun 11, 2022

For scientists, space is first and foremost a magnificent “playground” — an inexhaustible source of knowledge and learning that is assisting in the solution of some of the most fundamental existential issues concerning Earth’s origins and our place in the Universe. Curiosity has contributed significantly to the evolution of the human species. Curiosity along with the desire for a brighter future has driven humans to explore and develop from the discovery of fire by ancient ancestors to present space explorations.  Here is all the information you need and the best tips to write an essay on space exploration.

What is Space Exploration?  

Space Exploration is the use of astronomy and space technology to explore outer space. While astronomers use telescopes to explore space, both uncrewed robotic space missions and human spaceflight are used to explore it physically. One of the primary sources for space science is space exploration, which is similar to astronomy in its classical form. We can use space exploration to validate or disprove scientific theories that have been created on Earth. Insights into gravity, the magnetosphere, the atmosphere, fluid dynamics, and the geological evolution of other planets have all come from studying the solar system.

Advantages of Space Exploration 

It is vital to understand and point out the advantages of space exploration while writing an essay on the topic.

New inventions have helped the worldwide society. NASA’s additional research was beneficial to society in a variety of ways. Transportation, medical, computer management, agriculture technology, and consumer products all profit from the discoveries. GPS technology, breast cancer treatment, lightweight breathing systems, Teflon fibreglass, and other areas benefited from the space programme.

It is impossible to dispute that space exploration creates a large number of employment opportunities around the world. A better way to approach space exploration is to spend less and make it more cost-effective. In the current job market, space research initiatives provide far too much to science, technology, and communication. As a result, a large number of jobs are created.

Understanding

NASA’s time-travelling space exploration programmes and satellite missions aid in the discovery of previously unknown facts about our universe. Scientists have gained a greater understanding of Earth’s nature and atmosphere, as well as those of other space entities. These are the research initiatives that alert us to impending natural disasters and other related forecasts. It also paves the way for our all-powerful universe to be saved from time to time.

Disadvantages of Space Exploration

Highlighting disadvantages will give another depth to your essay on space exploration. Here are some important points to keep in mind.

Pollution is one of the most concerning issues in space travel. Many satellites are launched into space each year, but not all of them return. The remnants of such incidents degrade over time, becoming debris that floats in the air. Old satellites, various types of equipment, launch pads, and rocket fragments all contribute to pollution. Space debris pollutes the atmosphere in a variety of ways. Not only is space exploration harmful to the environment, but it is also harmful to space.

A government space exploration programme is expensive. Many people believe that space mission initiatives are economical. It should be mentioned that NASA just celebrated its 30th anniversary with $196.5 billion spent.

Space exploration isn’t a walk in the park. Many historical occurrences demonstrate the dangers that come with sad situations. The Challenger space shuttle accident on January 28, 1986, must be remembered. The spacecraft exploded in under 73 seconds, resulting in a tremendous loss of life and property.

Conclusion 

There are two sides to every coin. To survive on Earth, one must confront and overcome obstacles. Space exploration is an essential activity that cannot be overlooked, but it can be enhanced by technological advancements.

Space Exploration Courses

Well, if your dream is to explore space and you want to make a career in it, then maybe space exploration courses are the right choice for you to turn your dreams into reality.

Various universities offering space exploration courses are :

• Arizona State University, USA
• Bachelor of Science in Earth and Space Exploration
• Earth and Space Exploration (Astrobiology and Biogeosciences)
• Earth and Space Exploration (Astrophysics)
• University of Leicester, UK
• Space Exploration Systems MSc
• York University
• Bachelor of Engineering (BEng) in Space Engineering

Tips to write an IELTS Essay  on Space Exploration

• The essay’s word count should be at least 250 words. There is no maximum word count. If you write less than 250 words, you risk submitting an incomplete essay. The goal should be to write a minimum of 250-words essay.
• There will be more than one question on the essay topic. The questions must be answered in their entirety. For example, for the topic ‘crime is unavoidable,’ you might see questions like 1. Speak in favour of and against this topic, 2. Give your opinion, and 3. Suggest some measures to avoid crime. This topic now has three parts, and all of them must be answered; only then will the essay be complete.
• Maintain a smooth writing flow. You can’t get off track and create an essay that has nothing to do with the issue. The essay must be completely consistent with the question. The essay’s thoughts should be tied to the question directly. Make use of instances, experiences, and concepts that you can relate to.
• Use a restricted number of linking phrases and words to organise your writing. Adverbial phrases should be used instead of standard linking words.
• The essay should be broken up into little paragraphs of at least two sentences each. Your essay should be divided into three sections: introduction, body, and conclusion. ( cheapest pharmacy to fill prescriptions without insurance )
• Don’t overuse complicated and long words in your essay. Make appropriate use of collocations and idioms. You must be able to use words and circumstances effectively.
• The essay must be written correctly in terms of grammar. In terms of spelling, grammar, and tenses, there should be no mistakes. Avoid using long, difficult sentences to avoid grammatical problems. Make your sentences succinct and to-the-point.
• Agree/disagree, discuss two points of view, pros and disadvantages, causes and solutions, causes and effects, and problem-solution are all examples of essay questions to practise.
• Make a strong beginning. The opening should provide the reader a good indication of what to expect from the rest of the article. Making a good first impression and piquing your attention starts with a good introduction.
• If required, cite facts, figures, and data. It’s best to stay away from factual material if you’re not sure about the statistics or stats. If you’re unsure about something, don’t write it down.
• The essay’s body should be descriptive, with all of the points, facts, and information listed in great detail.
• The conclusion is the most noticeable part. Your IELTS band is influenced by how you end your essay.
• Make sure there are no spelling errors. If you’re not sure how to spell something, don’t use it. It is preferable to utilize simple, everyday terms.
• Do not include any personal or casual remarks. It is strictly forbidden.
• Once you’ve finished drafting your essay, proofread it. It enables you to scan for minor and large grammar and spelling problems.

This was the Essay on Space Exploration. We hope it was helpful to you. Experts at Leverage Edu will help you out in writing your essays for IELTS, SOPs and more!

Sonal is a creative, enthusiastic writer and editor who has worked extensively for the Study Abroad domain. She splits her time between shooting fun insta reels and learning new tools for content marketing. If she is missing from her desk, you can find her with a group of people cracking silly jokes or petting neighbourhood dogs.

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Impact Of Satellite TV On Our Culture

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What Is the James Webb Space Telescope?

An animation illustrating what the James Webb Space Telescope Looks like. Credit: NASA’s Goddard Space Flight Center (modified)

The James Webb Space Telescope is the largest, most powerful space telescope ever built. It will allow scientists to look at what our universe was like about 200 million years after the Big Bang . The telescope will be able to capture images of some of the first galaxies ever formed. It will also be able to observe objects in our solar system from Mars outward, look inside dust clouds to see where new stars and planets are forming and examine the atmospheres of planets orbiting other stars.

Here are some fun facts about the James Webb Space Telescope:

It is very, very big.

The Webb telescope is as tall as a 3-story building and as long as a tennis court! It is so big that it has to fold origami-style to fit inside the rocket to launch. The telescope will unfold, sunshield first, once in space.

The James Webb Space Telescope is about the same size as a tennis court and about as tall as a 3-story building! Credit: NASA/JPL-Caltech

It can see through dust clouds.

Infrared cameras can see through dust and smoke. Credit: NASA/IPAC/Pasadena Fire Dept.

The James Webb Space Telescope sees the universe in light that is invisible to human eyes. This light is called infrared radiation , and we can feel it as heat. Firefighters use infrared cameras to see and rescue people through the smoke in a fire. The James Webb Space Telescope will use its infrared cameras to see through dust in our universe. Stars and planets form inside those dust clouds, so peeking inside could lead to exciting new discoveries! It will also be able to see objects (like the first galaxies) that are so far away that the expansion of the universe has made their light shift from visible to infrared!

It wears a "hat" to help block heat and light from the Sun.

This animation shows how the sunshield will unfold when the Webb telescope reaches its home in orbit. Credit: NASA

The Webb telescope’s cameras are sensitive to heat from the Sun. Just like you might wear a hat or a visor to block the Sun from your eyes, Webb has a sunshield to protect its instruments and mirrors. The telescope’s sunshield is about the size of a tennis court. The temperature difference between the sun-facing and shaded sides of the telescope is more than 600 degrees Fahrenheit!

It uses giant, gold-coated mirrors to see the universe.

Engineers inspecting the Webb telescope’s mirrors at NASA’s Goddard Space Flight Center. Credit: NASA/Chris Gunn

Space telescopes “see” by using mirrors to collect and focus light from distant stars. ( Check out our telescopes page to learn more about how space telescopes work.) The bigger the mirror, the more details the telescope can see. It’s very difficult to launch a giant, heavy mirror into space. So, engineers gave the Webb telescope 18 smaller mirrors that fit together like a puzzle. The mirrors fold up inside the rocket, then unfold to form one large mirror in orbit.

Why are the mirrors gold? A thin layer of gold helps the mirrors reflect infrared light!

It will be hunting for signs of life on other planets.

Could life survive on this faraway planet? Astronomers study the light from stars and planets to see if they might have the ingredients for life. Animation credit: NASA/ESA/Dani Player (STScI), Music credit: Steve Combs

Our solar system isn’t the only home for planets! Scientists have discovered thousands of planets orbiting stars other than our Sun. These are called exoplanets . The James Webb Space Telescope will help to study the atmospheres of exoplanets. Could the atmospheres of some exoplanets hold the building blocks for life? We will find out soon!

What is the James Webb Space Telescope doing right now?

The James Webb Space Telescope launched on December 25, 2021. Want to stay up to date and learn more about NASA’s biggest and most powerful telescope? Check out this cool timeline to learn what the telescope is doing right now! Also, Find more facts, photos, videos and more at the James Webb Space Telescope Website !

Related resources from NASA

NASA Exoplanets: What is the habitable zone? James Webb Space Telescope Poster Lesson Plans, Activities, Resources & Programs For Informal Education Teachable Moment: Learn About the Universe With the James Webb Space Telescope

If you liked this, you may like:

Starlink satellites: Facts, tracking and impact on astronomy

Are Starlink satellites a grand innovation or an astronomical menace?

How to see starlink satellites

• Impact on astronomy

Expert Q&A

• Collision risk
• End of lifespan: Deorbiting

V2 Starlinks

• Use in emergencies
• Future plans
• How do they work?
• How can I get Starlink internet?

Additional resources

Bibliography.

Starlink is the name of a satellite network developed by the private spaceflight company SpaceX to provide low-cost internet to remote locations. 

A Starlink satellite has a lifespan of approximately five years and SpaceX eventually hopes to have as many as 42,000 satellites in this so-called megaconstellation.

The current V2 Starlink satellite version weighs approximately 1,760 lbs  (800 kilograms) at launch, almost three times heavier than the older generation satellites (weighing in at 573 lbs or 260 kg), according to Spaceflight Now . 

Related: Wild solar weather is causing satellites to plummet from orbit  

How many Starlink satellites are in orbit?

As of May 2024, there are 6,078 Starlink satellites in orbit , of which 6,006 are working , according to Astronomer Jonathan McDowell who tracks the constellation on his website .

The size and scale of the Starlink project concerns astronomers, who fear that the bright, orbiting objects will interfere with observations of the universe , as well as spaceflight safety experts who now see Starlink as the number one source of collision hazard in Earth's orbit. In addition to that, some scientists worry that the amount of metal that will be burning up in Earth's atmosphere as old satellites are deorbited could trigger unpredictable changes to the planet's climate. 

Starlink satellites orbit approximately 342 miles (550 kilometers) above Earth and put on a spectacular show for observers as they move across the sky. This show is not welcomed by all and can significantly hinder both optical and radio astronomical observations. 

You don't need any special equipment to see Starlink satellites as they are visible to the unaided eye. The satellites can appear as a string of pearls or a "train" of bright lights moving across the night sky . Starlink satellites are easier to see a day or two after their launch and deployment then become progressively harder to spot as they climb to their final orbital height of around 342 miles (550 km). 

Related: Starlink satellite train: How to see and track it in the night sky

Our list of the best stargazing apps may help you with your Starlink viewing planning. If you want to see where all of the Starlink satellites are located in real-time check out this Starlink map showing the global coverage of each Starlink satellite as well as information on how many are currently in service, inactive or have burned up in Earth's atmosphere. 

Related: How to photograph Starlink satellites guide .

Starlink coverage

To see current Starlink internet availability around the world, and if it's available where you are, Starlink has an interactive map detailing locations where Starlink internet is available, which areas are on the waitlist as well as areas that are "coming soon". 

"Starlink is ideally suited for areas where connectivity has been unreliable or completely unavailable," the Starlink main page states. "People across the globe are using Starlink to gain access to education, health services and even communications support during natural disasters."

More information about Starlink setup, along with answers to frequently answered questions, are available on the customer service page .

The history of Starlink

SpaceX's satellite internet proposal was announced in January 2015. Though it wasn't given a name at the time, CEO Elon Musk said that the company had filed documents with international regulators to place about 4,000 satellites in low Earth orbit.

"We're really talking about something which is, in the long term, like rebuilding the internet in space," Musk said during a speech in Seattle when revealing the project. 

SpaceX's satellite internet proposal was announced in January 2015. Though it wasn't given a name at the time, CEO Elon Musk said that the company had filed documents with international regulators to place about 4,000 satellites in Low Earth Orbit .

Musk's initial estimate of the number of satellites soon grew, as he hoped to capture a part of the estimated $1 trillion worldwide internet connectivity market to help achieve his Mars colonization vision . The U.S. Federal Communications Commission (FCC) has granted SpaceX permission to fly 12,000 Starlink satellites, and the company has filed paperwork with an international regulator to loft up to 30,000 additional spacecraft . 

To put that into perspective, as of Nov. 7, 2022, only 14,450 satellites have been launched in all of history with 6,800 currently active according to the European Space Agency (ESA).

SpaceX launched its first two Starlink test craft, named TinTinA and TinTinB, in February 2018. The mission went smoothly. Based on initial data, the company asked regulators for its fleet to be allowed to operate at lower altitudes than originally planned, and the FCC agreed .

The first 60 Starlink satellites launched on May 23, 2019, aboard a SpaceX Falcon 9 rocket . The satellites successfully reached their operational altitude of 340 miles (550 kilometers). 

Starlink's impact on astronomy

Within days of the first 60-satellite Starlink launch, skywatchers spotted a linear pearl string of lights as the spacecraft whizzed overhead in the early morning. Web-based guides showed others how to track down the spectacular display. 

"This was quite an amazing sight, and I was shouting 'Owowowow!' when the bright 'train' of objects entered into view," Netherlands-based satellite tracker Marco Langbroek told Space.com in 2019 via email. "They were brighter than I had anticipated."

That brightness was a surprise to almost everyone, including both SpaceX and the astronomical community. Researchers began to panic and shared photos of satellite streaks in their data, such as this trail image from the Lowell Observatory in Arizona.

They expressed particular concerns about future images from highly sensitive telescopes such as the Vera Rubin Observatory (formerly known as the Large Synoptic Survey Telescope), which will study the entire universe in exquisite detail and is expected to come online in 2022. Radio astronomers are also planning for interference from Starlink's radio-based antennas. 

In photos: SpaceX launches 60 Starlink satellites to orbit

The International Astronomical Union (IAU) expressed concerns in a statement released in June 2019. "Satellite constellations can pose a significant or debilitating threat to important existing and future astronomical infrastructures, and we urge their designers and deployers as well as policy-makers to work with the astronomical community in a concerted effort to analyze and understand the impact of satellite constellations," the statement said.

In April 2021, Thomas Schildknecht, the deputy director of the Astronomical Institute of the University of Bern, who represents Switzerland in the IAU, said at the European Space Agency's space debris conference that the union was calling on the United Nations to protect pristine night sky as cultural heritage against the uncontrolled expansion of megaconstellations.

In a report released in October 2022, the American Astronomical Society (ASS) likened the impact of megaconstellations on astronomy to light pollution. The report said the sky may brighten by a factor of two to three due to the diffuse reflection of sunlight off the spacecraft.

Related: Can you see stars in light polluted skies?

We spoke to Meredith Rawls is a stellar astronomer and software developer about the effects of low-Earth orbit satellites on ground-based astronomy. This interview was originally published in our sister magazine All About Space (Issue 119, July 2021).

Dr Meredith Rawls is a stellar astronomer and software developer working as a research scientist with the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) group at the University of Washington. As a software developer, Rawls is involved in developing algorithms that can identify objects in telescope data that have changed, and characterize them accordingly. Her work also entails researching how low-Earth orbit satellites affect astronomy and what satellite operator companies can do to reduce their impact on the night sky.  

How do low-Earth orbit satellites pose a problem for ground-based astronomy?

The main thing is there are so many of them that are currently being launched and planned to be launched and they reflect sunlight so they can be really bright. The brightness actually surprised some of the satellite operators, they had not anticipated how bright their satellites were actually going to be. Astronomers were used to sometimes seeing satellites, but now it's an order of magnitude more and they're going to be showing up very commonly in observations from ground-based telescopes.  

Are all aspects of astronomy affected?

I tend to be very biased towards the ground-based optical astronomy because that's our human experience with the night sky and they're the main kind of observations that I was trained in as a student. But radio astronomy is maybe even going to be more severely impacted than optical astronomy. It's complicated. 

Radio astronomers have been competing for years for a frequency spectrum, they have this national and international relations about who gets what frequencies on the radio spectrum, for example your mobile phone service, your WiFi, any gadget that transmits has to have approval. Radio astronomers have fought long and hard to make their presence known and say "we need this chunk of the spectrum because that’s where Hydrogen emits, we can't change that", in the U.S. they go to lobbying meetings to make their voices heard, so there is already a presence of radio astronomers in some of these regulatory spaces. 

The issue with growing numbers of low-Earth orbit satellite constellations is that one of the main goals they have is to send down high amounts of data for internet access so they'll be constantly beaming down loud radio signals down to Earth so people can get their internet connection. This is potentially going to cover a large amount of ground.

There are some things that they could do to try and lower the effects on radio astronomy, for example turning off their transmitters when they are over radio telescopes.

But the reality is that if you have located a set of frequencies that you are going to use, physically these waves spill over the edges, you cannot have a sharp cut off, it's just not how waves work. So even with the best intended regulations controlling what frequencies are being used by satellite companies, it is going to have some pretty serious effects on radio astronomy. 

If low-Earth orbit satellites are problematic, should the companies just place the satellites higher?

Actually that would be worse. It's a little complicated because you could think that maybe a lower orbit satellite would be brighter because it is closer, which is true but the trick is that it moves faster in a lower orbit because it has to not fall out of the sky. That means that when you are taking a picture it will move out of the way faster and the pixels won't linger long enough to make as bright of a streak in the image, which is better. 

So I was personally disappointed that OneWeb decided to keep their satellites at a higher altitude, whereas SpaceX have been more willing to keep their satellites at lower altitudes. Though space debris will become an even bigger problem at these lower altitudes as the lower the orbit, the more crowded it gets.

Starlink collision risk

SpaceX received additional backlash in September 2019, when the European Space Agency (ESA) announced that it had directed its Aeolus satellite to undertake evasive maneuvers and avoid crashing into "Starlink 44," one of the first 60 satellites in the megaconstellation. The agency took action after learning from the U.S. military that the probability of a collision was 1 in 1,000 — 10 times higher than ESA's threshold for conducting a collision-avoidance maneuver.

In August 2021, Hugh Lewis, the head of the Astronautics Research Group at the University of Southampton, U.K. and Europe's leading space debris expert, told Space.com that Starlink satellites represent the single main sources of collision risk in low Earth orbit. 

According to computer models, at that time, Starlink satellites were involved every week in about 1,600 encounters between two spacecraft closer than 0.6 miles (1 kilometer). That's about 50% of all such incidents. This number rises with every new batch of satellites launched into space. By the time Starlink deploys all 12,000 satellites of its first-generation constellation it could reach 90%, Lewis said.

Lewis also expressed concerns that Starlink's operator SpaceX, a newcomer into the satellite business, is now the single most dominant player in the field whose decisions can affect the safety of all operations in low Earth orbit.

End of lifespan deorbiting procedure

SpaceX plans to refresh the Starlink megaconstellation every five years with newer technology. At the end of their service, the old satellites will be steered into Earth's atmosphere where they will burn up. That is certainly commendable when it comes to space debris prevention, however, there is another problem. 

The vast amount of satellites that will be burning in the otherwise pristine upper layers of the atmosphere could alter the atmospheric chemistry and have unforeseen consequences for life on the planet. 

In a paper published in May 2021 in the journal Scientific Reports , Canadian researcher Aaron Boley said the aluminum the satellites are made of will produce aluminum oxide, also known as alumina, during burn-up. He warned that alumina is known to cause ozone depletion and could also alter the atmosphere's ability to reflect heat.

"Alumina reflects light at certain wavelengths and if you dump enough alumina into the atmosphere, you are going to create scattering and eventually change the albedo of the planet," Boley told Space.com .

That could lead to an out-of-control geoengineering experiment, a change in the Earth's climate balance. The effects of such alternations are currently unknown.

Karen Rosenlof, an atmospheric chemistry expert at the National Oceanic and Atmospheric Administration (NOAA), told Space.com she too was concerned about the effects of the particles from the burning satellites in the atmosphere. Rosenlof has expertise in modeling the effects of geoengineering interventions. 

David Fahey, the Director of NOAA's Chemical Sciences Laboratory, and Martin Ross, a physics and meteorology scientist at the Aerospace Corporation, both told Space.com that more research is urgently needed to understand the effects of burning increasing amounts of satellites in the atmosphere. 

The problem, the scientists said, is that in those high layers of the atmosphere, the particles are likely going to stay forever. Boley said that while the number of satellites burning in the atmosphere will be considerably smaller than the number of meteorites , the chemical composition of the artificial objects is different, thus the presence of the products of their burning is something scientists know nothing about. 

"We have 54 tonnes (60 tons) of meteoroid material coming in every day," Boley said. "With the first generation of Starlink, we can expect about 2 tonnes (2.2 tons) of dead satellites reentering Earth's atmosphere daily. But meteoroids are mostly rock, which is made of oxygen, magnesium and silicon. These satellites are mostly aluminum, which the meteoroids contain only in a very small amount, about 1%."

As the accumulation of those particles would increase over time, so would the intensity of the effects. It thus cannot be ruled out that over decades the pollution from burning megaconstellation satellites could lead to changes on a scale akin to what we are currently experiencing with fossil-fuel-induced climate change . 

"Humans are exceptionally good at underestimating our ability to change the environment," said Boley. "There is this perception that there is no way that we can dump enough plastic into the ocean to make a difference. There is no way we can dump enough carbon into the atmosphere to make a difference. But here we are. We have a plastic pollution problem with the ocean, we have climate change ongoing as a result of our actions and our changing of the composition of the atmosphere and we are poised to make the same type of mistake by our use of space."

Starlink did not respond to Space.com requests for comment.

A Starlink satellite's lifespan can also be cut short by powerful geomagnetic storms.

On Feb. 3, 2022, a SpaceX Falcon 9 rocket made a routine and successful launch of 49 Starlink satellites from NASA's Kennedy Space Center in Florida. But only a day later, a geomagnetic storm above Earth pushed up the density of the atmosphere, increasing the drag on the satellites and dooming the bulk of them to an early death.

"Preliminary analysis show the increased drag at the low altitudes prevented the satellites from leaving safe mode to begin orbit-raising maneuvers, and up to 40 of the satellites will reenter or already have reentered the Earth's atmosphere," SpaceX wrote in an update on Feb. 8, 2022. 

Read more: Better space weather forecast could have saved SpaceX Starlink satellites from solar storm

SpaceX began launching an upgraded version of Starlink, called the V2 mini, on  February 27, 2023 . The V2 minis serve as a precursor version to the company's full V2 design, whose larger design is intended to launch on SpaceX's yet-operational Starship rocket. In the interim, the V2 minis stand in as a measurable upgrade from Starlink's previous version.

Starlink V2 minis are more robust than the first generation, in both size and capability. According to SpaceX's  social media posts , the upgrades include  argon Hall thrusters  for a 2.4x and 1.5x boost in thrust and impulse, respectively, refitted phased array antennas, and E-band backhaul use capabilities that nearly quadruple Starlink's data capacity. 

The full version V2 satellites won't launch until SpaceX's Starship is fully operational. When they do, the larger V2 satellites will possess an even higher data capacity than their predecessors, and the ability to provide services direct to cellular devices. SpaceX CEO Elon Musk and T-Mobile CEO Mike Sievert announced a deal between the two companies in August 2022, and plan to provide the service to T-Mobile customers once Starlink V2 begins to launch.

Starlink satellite use in emergencies

With the right equipment, access to Starlink internet can be achieved in remote locations within just a few minutes, making it a useful resource in emergencies. 

According to a statement on Starlink's official website "Without the bounds of traditional ground infrastructure, Starlink can be deployed in a matter of minutes to support emergency responders in disaster scenarios." 

"The Starlink team is proud to support and prioritize service for emergency responders around the globe and will continue to grow this support as our coverage areas expand." The statement continues. 

The benefits of Starlink internet service in emergencies have already been demonstrated in Ukraine and Tonga. 

Starlink, SpaceX's giant and ever-growing broadband constellation, has been a vital piece of Ukrainian communications infrastructure throughout the ongoing Russian invasion . Ukrainian government officials publicly requested Starlink terminals on Feb. 26, just two days after the invasion began, and the first ones arrived in the country on Feb. 28.

In early April, SpaceX and the U.S. Agency for International Development announced they had jointly delivered about 5,000 Starlink terminals to Ukraine, with SpaceX directly providing more than 3,000 of them. The number has grown considerably since then, to 25,000 or so, according to company founder and CEO Elon Musk .

The situation in Ukraine was not always smooth, as Musk noted in March 2022 that the Starlink terminals have been jammed near Ukraine conflict areas. The company was already working on an upgrade when Musk announced this, and he pledged a further pivot to cyber defense to keep the Starlinks operational.

In February 2022, at least 50 Starlink terminals were sent to the island nation of Tonga in the Pacific Ocean. The goal was to give its residents free Internet access, especially in remote villages. Tonga needed the terminals after suffering a massive volcano eruption and tsunami in January. At the time, SpaceX said the terminals will allow for communications to flow in some of the regions with the worst effects due to the eruption according to Reuters .

SpaceX's plans for Starlink

SpaceX has stated that it will work with organizations and space agencies to mitigate the impacts of its megaconstellation. And the company has tried to assuage astronomers' concerns over Starlink's effect on the night sky. 

"SpaceX is absolutely committed to finding a way forward so our Starlink project doesn't impede the value of the research you all are undertaking," Patricia Cooper, SpaceX's vice president of satellite government affairs, told astronomers at a January 2020 meeting of the American Astronomical Society in Honolulu, Nature reported . 

SpaceX has taken action to this effect. For example, recently launched Starlink satellites sport visors designed to prevent sunlight from glinting too brightly off their most reflective parts. 

But the huge numbers of satellites in megaconstellations from SpaceX and other private space companies, such as OneWeb, suggest that light pollution and other issues may continue, and advocates have called for greater regulations from government agencies. 

"Here is a gift for the leaders of the world, a task more non-partisan than any other which has come before: protect our skies," stargazer Arwen Rimmer wrote in The Space Review , a weekly online publication devoted to essays and commentary about space, in early 2020. 

How do Starlink satellites work?

The current version of each Starlink satellite weighs 573 lbs. (260 kilograms) and is, according to Sky & Telescope magazine , roughly the size of a table. 

Rather than sending internet signals through electric cables, which must be physically laid down to reach far-flung places, satellite internet works by beaming information through the vacuum of space, where it travels 47% faster than in fiber-optic cable, Business Insider reported. 

Current satellite internet works using large spacecraft that orbit 22,236 miles (35,786 km) above a particular spot on Earth. But at that distance, there are generally significant time delays in sending and receiving data. By being closer to our planet and networking together, Starlink's satellites are meant to carry large amounts of information rapidly to any point on Earth, even over the oceans and in extremely hard-to-reach places where fiber-optic cables would be expensive to lay down. 

Users on the ground access the broadband signals using a kit sold by SpaceX. The kit contains a small satellite dish with a mounting tripod, a wifi router, cables and a power supply, according to the company's website .

How you can access Starlink's internet service

SpaceX has a dedicated website to order Starlink terminals. Go to the main page of the Starlink website and scroll down to the section that says " Order Now ." 

After plugging in your service address, you can see whether Starlink is available for your region. While pricing varies by region, a search for an address in Brooklyn in November 2022 gave a hardware price of $599.00, a one-time shipping and handling charge of $50.00, and a monthly service charge of $110.00.

Speeds are said to be much faster for many users in rural regions compared to local options, although again, this varies by region. "Users can expect to see download speeds between 100 Mb/s and 200 Mb/s, and latency as low as 20ms in most locations," the home page states.

Once your box arrives, you should see within it a Starlink kit that will allow you to connect to the Internet. A Starlink app, as well as a website user guide, are meant to guide you through the installation.

Explore Starlink satellites in more detail with this informative video from SpaceX . Read how astrophysicist Ethan Siegel thinks SpaceX can fix the damage Starlink satellites are causing to astronomy, published in Forbes . 

NOIRLab, Report of the SATCON2 Workshop: Executive Summary, July 16, 2021 https://noirlab.edu/public/media/archives/techdocs/pdf/techdoc031.pdf

Boley, A., Byers, M. Satellite mega-constellations create risks in Low Earth Orbit, the atmosphere and on Earth, Scientific Reports, 20 May, 2021 https://www.nature.com/articles/s41598-021-89909-7

McDowell, J. The Low Earth Orbit Satellite Population and Impacts of the SpaceX Starlink Constellation, The Astrophysical Journal Letters, April 6 2020 https://iopscience.iop.org/article/10.3847/2041-8213/ab8016/meta

Massey R. et al. The challenge of satellite megaconstellations, Nature Astronomy, 6 November, 2020                                                  https://www.nature.com/articles/s41550-020-01224-9

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Tereza is a London-based science and technology journalist, aspiring fiction writer and amateur gymnast. Originally from Prague, the Czech Republic, she spent the first seven years of her career working as a reporter, script-writer and presenter for various TV programmes of the Czech Public Service Television. She later took a career break to pursue further education and added a Master's in Science from the International Space University, France, to her Bachelor's in Journalism and Master's in Cultural Anthropology from Prague's Charles University. She worked as a reporter at the Engineering and Technology magazine, freelanced for a range of publications including Live Science, Space.com, Professional Engineering, Via Satellite and Space News and served as a maternity cover science editor at the European Space Agency.

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• 24launch Honestly, I'm really growing weary of Ms Pultarova's non-stop personal FUD (Fear, uncertainty and doubt) campaign against Starlink. Every article of hers lately is drama, hyperbole and complete negativity against Starlink, the bulk is absolute nonsense or concerns of some "expert" with questionable motivations. She needs to move on. Her personal ties to the old legacy "Viasat" companies are more than obvious. Please stop writing this kind of garbage. Some examples from the article: The size and scale of the Starlink project concerns astronomers, who fear that the bright, orbiting objects will interfere with observations of the universe... Guess what? Starlink is the ONLY company IN THE WORLD actively working with the National Science Foundation and the IAU to try to mitigate the impact on the astronomical community. Amazon has repeatedly declined the invitations. OneWeb has declined to discuss their satellites with the IAU. Starlink has already made many changes to dramatically decrease the reflectivity including putting solar shields to lower the reflectivity. Also, in previous articles she has posted an image of massive star trails that keeps making it's way around the internet in a negative campaign orchestrated by the old sat companies (Viasat & Hughes) and in the fact image is NOT of Starlink trails but trails made by GEO sats as the Zwicky Transient telescope stays locked on the stars thus rotates with the Earth. In addition to the working to try to mitigate the visual impact, Starlink is working on minimizing the radio interference. Ms Pultarova had a FUD article a week ago that stated that Starlink negatively imacts radio astronomy. But the actual reference article said they "could" interfere with certain frequences that might be potentially used for radio science. But the researchers acknowledged in that article that these frequencies were not currently ones that Starlink had been required to not interfere with and further acknowledged that Starlink was in full compliance with regards to the frequencies most used and that they were requried to not interfer with. Also, THIS statement from the NSF: SpaceX also committed to coordinating with radio astronomy facilities to prevent Starlink satellites from beaming communications during observations. SpaceX and the NSF’s National Radio Astronomy Observatory (NRAO) completed several field tests with more tests planned to verify that radio astronomy observations will not be impacted. Another nonsense statement from her "article": spaceflight safety experts who now see Starlink as the number one source of collision hazard in Earth's orbit. Absolutely untrue. The number one source of collision harzard is and will remain for some time debris from ASAT tests over the last few years as well as legacy satellites exploding/disintigrating on their own. Go have a look at Space Command's website. Starlink satellites are currently the ONLY satellites that have automatic collision detection and avoidence. Amazon's Kuiper? They declinced to comment. OneWeb? No means to do so. And THIS??? In addition to that, some scientists worry that the amount of metal that will be burning up in Earth's atmosphere as old satellites are deorbited could trigger unpredictable changes to the planet's climate. What utter nonsense! As JMB117 pointed out she fails to acknowledge the tons of space debris that burn up in the Earth's atmosphere on a daily basis. She can bash Starlink all she wants but other companies will soon be coming online, as I mentioned Amazon's Kuiper network with 12,000+ satellites. Google is looking into it and now the traditional geo sat companies like Hughes/Dish are interested in mega clusters in LEO. Additionally the Air Force and Space Force are seeing the benefit to large clusters of LEO satellies. Lest we forget other countries like China are working on their own mega clusters. Ms Pultarova mentions in her bio she's an aspiring fiction writer. It looks to me like she's nailed it and should move on to pursuing that endevour. Reply

UFOareAngels said: I love your article. Yes! Starlink is a menace and should be taken down immediately.. It is polluting the skies! Countless people including my family from 3rd world countries are calling them aliens! Even so.. it so 20th century.. ground transmissiom has come a long way.. why have to deal with deterioraring satellites? honestly it could just be a coverup for military operations.. spacex does have military contracts

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403 Words Essay on the importance of Satellites

Satellites orbit the earth. Through electronic eyes from hundreds of miles overhead, the satellites lead prospectors to mineral deposits invisible on earth’s surface. Relaying communications at the speed of light, they shrink the planet until its most distant people are only a split second apart.

They beam world weather to our living room TV and guide ships through storms. Swooping low over areas of possible hostility, spies in the sky maintain surveillance that helps keep peace in a volatile world.

How many objects, exactly, are orbiting out there? Today’s count is 4,914. The satellites begin with a launch, which in the U.S. takes place at Cape Canaveral in Florida, NASA’s Wallops Flight Center in Virginia, or, for polar orbiters, Vandenberg Air Force Base in California. A few simply vanish into the immensity of space.

When a satellite emerges from the rocket’s protective shroud, radioelement regularly reports on its health to round-the-clock crews of ground controllers. They watch over the temperatures and voltages of the craft’s electronic nervous system and other vital ‘organs’, always critical with machines whose sunward side may be 300 degrees hotter than the shaded part.

Once a satellite achieves orbit-that delicate condition in which the pull of earth’s gravity is matched by the outward fling of the crafts speed-subtle pressures make it go astray Solar flares make the satellite go out of orbit. Wisps of outer atmosphere drag its speed. Like strands of spider web, gravity fields of the earth, moon, and sun tug at the orbiting space farer.

Even the sunshine’s soft caress exerts a gentle nudge. Should a satellite begin to wander, ground crews fire small fuel jets that steer it back on course. This is done sparingly, for exhaustion of these gases ends a craft’s useful career. Under such stresses, many satellites last 2 years.

When death is only a second away, controllers may command the craft to jump into a high orbit, so it will move up away from earth, keeping orbital paths from becoming too cluttered. Others become ensnarled in the gravity web; slowly they are drawn into gravitational shat serve as space graveyards.

A satellite for communications would function like a great antenna tower, hundreds or even thousands of miles above the earth, capable of transmitting messages almost instantaneously across die oceans and continents. Soon after the launch of ATWS-6, (a satellite designed to aid people) NASA ground controllers trained its antenna on Appalachia.

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Essay on Satellite

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English Essay on “Artificial Satellites” Astronomy Essay, Paragraph, Speech for Class 6, 7, 8, 9, 10, 12 Exam.

Artificial satellites.

An artificial satellite is a manufactured object that continuously orbits Earth or some other body in space. Most artificial satellites orbit Earth. People use them to study the universe, help forecast the weather, transfer telephone calls over the oceans, assist in the navigation of ships and, aircraft, monitor crops and other resources, and support military activities.

Artificial satellites also have orbited the moon, the sun, asteroids, and the planets Venus, Mars, and Jupiter. Such satellites mainly gather information about the bodies they orbit.

Piloted spacecraft in orbit, such as space capsules, space shuttle orbiters, and space stations, are also considered artificial satellites.

So, too, are orbiting pieces of “space junk,” such as burned-out rocket boosters and empty fuel tanks that have not fallen to Earth. But this article does not deal with these kinds of artificial satellites.

Artificial satellites differ from natural satellites, natural objects that orbit a planet. Earth’s moon is a natural satellite. The Soviet Union launched the first artificial satellite, Sputnik 1, in 1957. Since then, the United States and about 40 other countries have developed, launched, and operated satellites. Today about 3000 useful satellites and 6,000 pieces of space junk are orbiting Erath.

Satellite orbits have a variety of shapes. Some are circular, while others are highly elliptical (egg-shaped). Orbits also vary in altitude. Some circular orbits, for example, are just above the atmosphere at an altitude of about 155 miles (250 kilometers), while others are more than 20,000 miles (32,200 kilometers) above Earth. The greater the altitude, the longer period — the time it takes a satellite to completer one orbit.

A satellite remains in orbit because of a balance between the satellite’s velocity (the speed at which it would travel in a straight line) and the gravitational force between the satellite and Earth. Were it not for the pull of gravity, a satellite’s velocity would send it flying away from Earth in a straight line. But were it not for velocity gravity would pull a satellite back to Earth.

To help understand the balance between gravity and ve consider what happens when a small weight has attached a lock to a string and swung in a circle. If the string were to break, the weight would fly off in a  line. like gravity, however, the string acts keeping the weight in its orbit. The weight and string can also show the relationship between a satellite’s altitude and its orbital period. A long string is like a high altitude. The weight takes a relatively long time to complete one circle. A short string is like a low altitude. The weight has a relatively short orbital period. orbital period.

Many types of orbits exist, but most artificial satellites orbiting Earth travel in one of four types:

(1) high altitude, geosynchronous,

(2) medium-altitude,

(3) un-synchronous, polar; and

(4) low altitude. Most orbits of these four types are circular.

A high altitude, geosynchronous orbit lies above the equator at an altitude of about 22,300 miles (35,900 kilometers). A satellite this orbit travels around Earth’s axis at exactly the same time, d in the same direction, as Earth rotates about its axis. Thus, as seen from Earth, the satellite always appears at the same place in the sky overhead. To boost a satellite into this orbit requires a large, powerful launch vehicle.

A medium-altitude orbit has an altitude of about 12,400 miles (20,000 kilometers) and an orbital period of 12 hours. The orbit is outside Earth’s atmosphere and is thus very stable. Radio signals sent from a satellite at medium altitudes can be received over a large area of Earth’s surface. The stability and wide coverage of the orbit make it ideal for navigation satellites.

A sun-synchronous, polar orbit has a fairly low altitude and passes almost directly over the North and South poles. A slow drift of the orbit’s position is coordinated with Earth’s movement around the sun in such a way that the satellite always crosses the equator at the same local time on Earth. Because the satellite flies over all latitudes, its instruments can gather information on almost the entire surface of Earth. One example of this type of orbit is that of the TERRA Earth Observing System’s NOAA-H satellite. This satellite studies how natural cycles and human activities affect Earth’s climate. The altitude of its orbit is 438 miles (705 kilometers), and the orbital period is 99 minutes. When the satellite crosses the equator, the local time is always either 10:30 a.m. or 10:30 p.m.

A low-altitude orbit is just above Earth’s atmosphere, where there is almost no air to cause drag on the spacecraft and reduce its speed. Less energy is required to launch a satellite into this type of orbit than into any other orbit. Satellites that point toward deep space and provide scientific information generally operate in this type of orbit. The Hubble Space Telescope, for example, operates at an altitude of about 380 miles (610 kilometers), with an orbital period of 97 minutes.

Artificial satellites are classified according to their mission. There are six main types of artificial satellites:

(1) scientific research,

(2) weather,

(3) communications,

(4) navigation,

(5) Earth-observing, and

(6) military.

Scientific research satellites gather data for scientific analysis. These satellites are usually designed to perform one of three kinds of missions. (1) Some gather information about the composition and effects of the space near Earth. They may be placed in any of various orbits, depending on the type of measurements they are to make. (2) Other satellites record changes in Earth and its atmosphere. Many of them travel in sun-synchronous, polar orbits. (3) Still others observe planets, stars, and other distant objects. Most of these satellites operate in low altitude orbits. Scientific research satellites also orbit other planets, the moon, and the sun.

Weather satellites help scientists study weather patterns and forecast the weather. Weather satellites observe the atmospheric conditions over large areas.

Some weather satellites travel in a sun-synchronous, polar orbit, from which they make close, detailed observations of weather over the entire Earth. Their instruments measure cloud cover, temperature, air pressure, precipitation, and the chemical composition of the atmosphere. Because these satellites always observe Earth at the same local time of day, scientists can easily compare weather data collected under constant sunlight conditions. The network of weather satellites in these orbits also functions as a search and rescue system. They are equipped to detect distress signals from all commercial, and many private, planes and ships.

Other weather satellites are placed in high-altitude, geosynchronous orbits. From these orbits, they can always observe weather activity over nearly half the surface of Earth at the same time. These satellites photograph changing cloud formations. They also produce infrared images, which show the amount of heat corning from Earth and the clouds.

Communications satellites serve as relay stations, receiving radio signals from one location and transmitting them to another. A communications satellite can relay several television programs or many thousands of telephone calls at once. Communications satellites are usually put in a high altitude, geosynchronous orbit over a ground station. A ground station has a large dish antenna for transmitting and receiving radio, signals. Sometimes, a group of low orbit communications satellites arranged in a network called a constellation, work together by relaying information to each other and to users on the ground. Countries and commercial organizations, such as television broadcasters and telephone companies, use these satellites continuously. Navigation satellites enable operators of aircraft, ships, and land vehicles anywhere on Earth to determine their locations with great accuracy. Hikers and other people on foot can also use satellites for this purpose. The satellites send out radio signals that are picked up by a computerized -receiver carried on a vehicle or held in the hand.

Navigation satellites operate in networks, and signals from a network can reach receivers anywhere on Earth. ‘file receiver calculates its distance from at least three satellites whose signals it has received. It uses this information to determine its location.

Earth-observing satellites are used to map and monitor our planet’s resources and ever-changing chemical life cycles. They follow sun-synchronoUs, polar orbits. Under constant, consistent illumination from the sun, they take pictures in different colors of visible light and non-visible radiation. Computers on Earth combine and analyze the pictures. Scientists Earth-observing satellites to locate mineral deposits, to determine the location and size of freshwater supplies, to identify sources of pollution and study its effects, and to detect the spread of disease in crops and forests.

Military satellites include weather, communications, navigation, and Earth-observing satellites used for military purposes. Some military satellites — often called “spy satellites” — can detect the launch of missiles, the course of ships at sea, and the movement of military equipment on the ground.

Every satellite carries special instruments that enable it to perform its mission. For example, a satellite that studies the universe has a telescope. A satellite that helps forecast the weather carries cameras to track the movement of clouds.

In addition to such mission-specific instruments, all satellites have basic subsystems, groups of devices that help the instruments work together and keep the satellite operating. For example, a power subsystem generates, stores, and distributes a satellite’s electric power. This subsystem may include panels of solar cells that gather energy from the sun. Command and data handling subsystems consist of computers that gather and process data from the instruments and execute commands from Erath.

A satellite’s instruments and subsystems are designed, built, and tested individually Workers install them on the satellite one at a time until the satellite is complete. Then the satellite is tested under conditions like those that the satellite will encounter during launch and while in space. If the satellite passes all tests, it is ready to be launched.

Launching the satellite: Space shuttles carry some satellites into` space, but most satellites are launched by rockets that fall into the ocean after their fuel is spent. Many satellites require minoi ustments of their orbit before they begin to perform their function. Built-in rockets called thrusters make these adjustments. Once a satellite is placed into a stable orbit, it can remain there for a long time without further adjustment.

Most satellites operate are directed from a control center o Earth. Computers and human operators at the control center monitor the satellite’s position, send instructions to its computers and retrieve information that the satellite has gathered. The control center communicates with the satellite by radio. Ground’ stations within the satellite’s range send and receive the radio signals.

A satellite does not usually receive constant direction from its control center. It is like an orbiting robot. It controls its solar panels to keep them pointed toward the sun and keeps its antennas ready to receive commands. Its instruments automatically collect information.

Satellites in a high altitude, geosynchronous orbit are always in contact with Earth. Ground stations can contact satellites in low orbits as often as 12 times a day. During each contact, the satellite transmits information and receives instructions. Each contact must be completed during the time the satellite passes overhead — about 10 minutes.

If some part of a satellite breaks down, but the satellite remains capable of doing useful work, the satellite owner usually will continue to operate it. In some cases, ground controllers can repair or reprogram the satellite. In rare instances, space shuttle, crews have retrieved and repaired satellites in space. If the satellite can no longer perform usefully and cannot be repaired or reprogrammed, operators from the control center will send a signal to shut it off.

A satellite remains in orbit until its velocity decreases and gravitational force pulls it down into a relatively dense part of the atmosphere. A satellite slows down due to the occasional impact of air molecules in the upper atmosphere and the gentle pressure of the sun’s energy. When the gravitational force pulls the satellite down far enough into the atmosphere, the satellite rapidly compresses the air in front of it. This air becomes so hot that most or all of the satellite burns up.

In 1955, the United States and the Soviet Union announced plans to launch artificial satellites. On Oct. 4, 1957, the Soviet Union launched Sputnik 1, the first artificial satellite. It circled Earth once every 96 minutes and transmitted radio signals that could be received on Earth. On Nov. 3, 1957, the Soviets launched a second satellite, Sputnik 2. It carried a dog named Laika, the first animal to soar in space. The United States launched its first satellite, Explorer 1, on Jan. 31, 1958, and its second, Vanguard 1, on March 17, 1958.

In August 1960, the United States launched the first communications satellite’ Echo I. This satellite reflected radio signals back to Earth. In April 1960, the first weather satellite, Tiros I, sent pictures of clouds to Earth. The U.S. Navy developed the first navigation satellites. The Transit 1B navigation satellite first orbited in April 1960. By 1965, more than 100 satellites were being placed in orbit each year.

Since the 1970s, scientists have created new and more effective satellite instruments and have made use of computers and miniature electronic technology in satellite design and construction. In addition, more nations and some private businesses have begun to purchase and operate satellites. By the early 2000s, more than 40 countries owned satellites, and nearly 3,000 satellites were operating in orbit.

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What Is the SAT Essay?

College Board

• February 28, 2024

The SAT Essay section is a lot like a typical writing assignment in which you’re asked to read and analyze a passage and then produce an essay in response to a single prompt about that passage. It gives you the opportunity to demonstrate your reading, analysis, and writing skills—which are critical to readiness for success in college and career—and the scores you’ll get back will give you insight into your strengths in these areas as well as indications of any areas that you may still need to work on.

The Essay section is only available in certain states where it’s required as part of SAT School Day administrations. If you’re going to be taking the SAT during school , ask your counselor if it will include the Essay section. If it’s included, the Essay section will come after the Reading and Writing and Math sections and will add an additional 50 minutes .

What You’ll Do

• Read a passage between 650 and 750 words in length.
• Explain how the author builds an argument to persuade an audience.
• Support your explanation with evidence from the passage.

You won’t be asked to agree or disagree with a position on a topic or to write about your personal experience.

The Essay section shows how well you understand the passage and are able to use it as the basis for a well-written, thought-out discussion. Your score will be based on three categories.

Reading: A successful essay shows that you understood the passage, including the interplay of central ideas and important details. It also shows an effective use of textual evidence.

Analysis: A successful essay shows your understanding of how the author builds an argument by:

• Examining the author’s use of evidence, reasoning, and other stylistic and persuasive techniques
• Supporting and developing claims with well-chosen evidence from the passage

Writing: A successful essay is focused, organized, and precise, with an appropriate style and tone that varies sentence structure and follows the conventions of standard written English.

Learn more about how the SAT Essay is scored.

Want to practice? Log in to the Bluebook™ testing application , go to the Practice and Prepare section, and choose full-length practice test . There are 3 practice Essay   tests. Once you submit your response, go to MyPractice.Collegeboard.org , where you’ll see your essay, a scoring guide and rubric so that you can score yourself, and student samples for various scores to compare your self-score with a student at the same level.

After the Test

You’ll get your Essay score the same way you’ll get your scores for the Reading and Writing and Math sections. If you choose to send your SAT scores to colleges, your Essay score will be reported along with your other section scores from that test day. Even though Score Choice™   allows you to choose which day’s scores you send to colleges, you can never send only some scores from a certain test day. For instance, you can’t choose to send Math scores but not SAT Essay scores.

Until 2021, the SAT Essay was also an optional section when taking the SAT on a weekend. That section was discontinued in 2021.

If you don’t have the opportunity to take the SAT Essay section as part of the SAT, don’t worry. There are other ways to show your writing skills as part of the work you’re already doing on your path to college. The SAT can help you stand out on college applications , as it continues to measure the writing and analytical skills that are essential to college and career readiness. And, if you want to demonstrate your writing skills even more, you can also consider taking an AP English course .

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Essay on “Satellite Communications” Complete Essay for Class 10, Class 12 and Graduation and other classes.

Satellite communications.

Satellite communications are the outgrowth of development in two main areas, space technology and communication technology. The first requirement for any space activity has, however, nothing to do with the state of technology since it concerns the ability to compute the velocity needed to escape earth’s gravity and, as a next step, to a satellite in orbit. This knowledge comes out of a very old branch of science, celestial mechanics which began when man first studied the motion of stars. The key technology in space flight generally is propulsion since the problem of launching objects into space revolves itself into securing initial thrust required to escape the gravitational attraction of the earth and to give the space object the velocity necessary to hold its course by the inertia of its motion. The ability to provide transportation services for a wide variety of spacecraft has progresses rapidly. The early efforts of the late 1950s involved modest mission any pay load requirements and were generally concerned with the launching of relatively simple space research experiments. The programme of the early 1960s expanded into such areas as lunar and inter-planetary probes. Today, a wide variety of spacecraft are launched on a routine basis. A family of proven launch vehicles exists which can be adapted to specific mission needs.

Rocket technology is more capable of accelerating useful payloads to the very high velocities required to orbit the earth, to escape the earth and go to the moon and the other planets and also of providing a high degree of precision when placing objects in orbit around the earth.

The existing rocketry power, to place satellite in orbit would, however, be of no practical value in the absence of efficient communication with the spacecraft. No meaningful activity in space would be possible without these. Space communication and computer technology depend on innovations and advances in electronics which started with the transistors invented in 1948. Since then the trend has been towards ever smaller, more reliable and versatile electronic devices which have become essential in aviation equipment, computers, space and communication industry.

The communication satellite is described as the climax of the revolution in communication and information which is to change our world into a global village. Some regard satellite communication as a further step towards still more powerful and all pervasive mass media whose contact binds individuals to a technocratic order. Others foresee a global mass of individuals more or less helplessly reeling under the impact of constant floods of incoherent information. Changes in the communication system which make it possible for more people to get access to more and a greater selection of information, education or entertainment might in themselves have far-reaching consequences, regardless of the content at a given moment. The sheer presence of television is expected to break the feeling of isolation in remote communities. The anxieties and fears that have been expressed with regard to the possibility of unwanted television broadcasts via satellites recognise  the importance of both the medium and the message, whatever, the theoretical position is taken. There is also a recognition of the much greater impact of television as compared to such a medium as short-wave radio as well as the concept of certain kinds of content being more acceptable – or unacceptable-than others.

It is often said that one of the main consequences of modern communication technology, as specifically represented by satellite communication, would be instantaneously and universally available information. The problem would then be one, not of availability, but of selectivity. This would imply the recognition of the need for new kinds of education so that “people can cope efficiently, imaginatively and perceptively with information overload” or of the important place held by the mass media, the significance of their goals, principles and practices.

However, these issues cannot be dealt with without some indications of the trends and possibilities and implications of satellite communication in the light of more clearly defined aspects. The implications may be seen from various points over view such as in response to such questions as to what kind of information can be or need be transmitted over satellites, according to what patterns, by whom, and for what purpose, in which context. The introduction of satellite communication occurs in widely different socio-economic, political and cultural contexts. The implications will, therefore, vary from country to country and region to region. One of the basic differences will be between those countries already possessing a well developed telecommunications and broadcasting network and nations with limited, inadequate facilities where geographical and other factors add to the difficulties in establishing nationwide net works. These two categories would generally but not completely correspond to the industrialised and developing areas of the world.

It has been said that satellite technology would be particularly unsuited to developing countries because it is expensive, technologically sophisticated and presents new problems when the present ones have not been solved. While admittedly the cost factor is an essential consideration, the scale of expenditure should not distract from an evaluation in terms of development goals that can be served in this way and in some cases in no other way. Moreover, the satellite system costs have fallen low enough to be within reach of developing countries, and to represent at least an option that should seriously be taken into account.

It has been recognised in various international bodies, primarily in the United Nations, that all efforts should be made to assist developing nations to benefit from space technology. It has been emphasized that if the developing countries continue to rely upon traditional, conventional techniques without taking the plunge into new technology, the gap between them and the technologically advanced countries will not close but continue to widen.

“Several peaceful applications of outer space can be applied now in developing countries to provide a new stimulus for progress. Above all, it is necessary to ensure that they are not compelled to follow through the same steps as were taken during the past century by those countries which are technologically advanced today. Many traditional technologies become much more cost effective if combined with space applications. The population explosion and the rapidly shrinking world do not permit delaying the benefits arising from space until the older methods have been developed. The question is not whether developing countries can afford the peaceful uses of outer space. Rather it is whether they can afford to ignore them”.

Another great inequality in today’s world, that must be overcome, lies in the disparity between the urban centre’s and the rural areas, which is particularly evident in the case of information and communication media. Traditionally, they are first established in the cities from where they slowly, if at all, penetrate the countryside. Terrestrial telecommunication and television networks almost never achieve full coverage. Therefore, “until the advent of space technology, many benefits of a modern society were available only to communities residing in large metropolitan areas or to those linearly connected to such areas. Through communication satellites, it is now possible to reach isolated communities dispersed over a large region without suffering economic penalty. This aspect of space technology is of particular significance to developing countries where agriculture plays a preponderant role and substantial sections of the population are non-urban with a low level of literacy.

“Education as well as information inputs which might contribute to motivation for modernisation, the use of new techniques in the production of food, improved health and sanitation, can all be provided much more readily if reliable audio-visual communication link can be established nation-wide. Moreover, many developing countries face an acute problem arising from social force of disintegration. Their continued viability is dependent on the integration of many religious, tribal, and regional groups which have distinct cultural and political traditions. A single system of mass communications providing a common-shared experience to the entire population can perform an important role in making credible the oneness of the territory.”

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Nasa launches second small climate satellite to study earth’s poles, jennifer m. dooren, nasa headquarters, jet propulsion laboratory.

Editor’s note: This release was updated June 6, 2024, to correct the launch time in the photo caption.

The second of NASA’s PREFIRE (Polar Radiant Energy in the Far-InfraRed Experiment) two satellites is communicating with ground controllers after launching at 3:15 p.m. NZST, Wednesday (11:15 p.m. EDT, June 4). Data from these two shoebox-size cube satellites, or CubeSats, will better predict how Earth’s ice, seas, and weather will change in a warming world — providing information to help humanity thrive on our changing planet.  

The CubeSat launched on top Rocket Lab’s Electron rocket from the company’s Launch Complex 1 in Māhia, New Zealand, and follows the May 25 launch of the first PREFIRE CubeSat. After a 30-day checkout period, when engineers and scientists confirm both CubeSats are operating normally, the mission is expected to operate for 10 months.

“By helping to clarify the role that Earth’s polar regions play in regulating our planet’s energy budget, the PREFIRE mission will ultimately help improve climate and ice models,” said Amanda Whitehurst, PREFIRE program executive, at NASA Headquarters in Washington. “Improved models will benefit humanity by giving us a better idea of how our climate and weather patterns will change in the coming years.”

Capitalizing on NASA’s unique vantage point in space, PREFIRE will help understand the balance between incoming heat energy from the Sun and the outgoing heat given off at Earth’s poles. The Arctic and Antarctica act something like the radiator in a car’s engine shedding much of the heat initially absorbed at the tropics back into space. The majority of that heat is emitted as far-infrared radiation. The water vapor content of the atmosphere, along with the presence, structure, and composition of clouds, influences the amount of radiation that escapes into space from the poles.

The PREFIRE mission will give researchers information on where and when far-infrared energy radiates from the Arctic and Antarctic environments into space. The mission also will use its two CubeSats in asynchronous, near-polar orbits to study how relatively short-lived phenomena like cloud formation, moisture changes, and ice sheet melt affect far-infrared emissions over time. The two satellites pass over the same part of Earth at different times of day, giving researchers information on changing conditions.

“Climate change is reshaping our environment and atmosphere in ways that we need to prepare for,” said Brian Drouin, PREFIRE’s deputy principal investigator at NASA’s Jet Propulsion Laboratory in Southern California. “This mission will give us new measurements of the far-infrared wavelengths being emitted from Earth’s poles, which we can use to improve climate and weather models and help people around the world deal with the consequences of climate change.”

Each CubeSat carries an instrument called a thermal infrared spectrometer, which uses specially shaped mirrors and sensors to measure infrared wavelengths. Miniaturizing the instruments to fit on CubeSats required downsizing some parts while scaling up other components.

“Equipped with advanced infrared sensors that are more sensitive than any similar instrument, the PREFIRE CubeSats will help us better understand Earth’s polar regions and improve our climate models,” said Laurie Leshin, director at NASA JPL. “Their observations will lead to more accurate predictions about sea level rise, weather patterns, and changes in snow and ice cover, which will help us navigate the challenges of a warming world.”

NASA’s Launch Services Program, based out of the agency’s Kennedy Space Center in Florida, in partnership with NASA’s Earth System Science Pathfinder Program, is providing the launch service as part of the agency’s Venture-class Acquisition of Dedicated and Rideshare ( VADR ) launch services contract.

The PREFIRE mission was jointly developed by NASA and the University of Wisconsin-Madison. NASA JPL manages the mission for the agency’s Science Mission Directorate and provided the spectrometers. Blue Canyon Technologies built the CubeSats and the University of Wisconsin-Madison will process the data the instruments collect. The launch services provider is Rocket Lab USA Inc. of Long Beach, California.

To learn more about PREFIRE, visit:

https://science.nasa.gov/mission/prefire/

Karen Fox / Elizabeth Vlock

Headquarters, Washington

202-358-1600

[email protected] / [email protected]

Jane J. Lee / Andrew Wang

Jet Propulsion Laboratory, Pasadena, Calif.

818-354-0307 / 626-379-6874

[email protected] / [email protected]

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Optional key stage 1 tests: 2024 mathematics test materials

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2024 key stage 1 mathematics Paper 1: arithmetic

Ref: ISBN 978-1-83507-022-2, STA/24/8807/e

PDF , 538 KB , 20 pages

2024 key stage 1 mathematics Paper 2: reasoning

Ref: ISBN 978-1-83507-023-9, STA/24/8808/e

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2024 key stage 1 mathematics - administering Paper 1: arithmetic

Ref: ISBN 978-1-83507-140-3, STA/24/8825/e

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