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Astronomy magazine typically explores the frontiers of space through observatories positioned far above our planet. However, an extensive network of Earth-sensing satellites focuses on monitoring our home from various angles.
These satellites play a crucial role in examining weather patterns, climate shifts, ocean currents, and land use, offering comprehensive insights into the dynamics of our environment. According to the United States Geological Survey, over 693 Earth-sensing satellites are cataloged, even including those no longer operational. These satellites operate independently or collaboratively, orbiting our planet at different altitudes and employing diverse technologies such as visible, radio, and infrared wavelengths, along with radar and laser systems. Here, we explore a selection of these pivotal satellites that enhance our understanding of Earth.
TIROS-1
As the very first weather satellite, TIROS-1 (Television Infrared Observation Satellite) revolutionized meteorological science. This pioneering satellite was launched in April 1960, at a time when the utility of space-based weather observation was widely uncertain. Despite producing monochromatic and somewhat grainy images by today’s standards, TIROS-1 offered unprecedented views of cloud formations, significantly enhancing weather forecasting, agricultural planning, and disaster preparedness. Its brief operational life of 78 days sparked a legacy of advancements in remote sensing.
By 1962, the TIROS program achieved continuous data collection, paving the way for a succession of satellites developed through collaborations between NASA and the National Oceanic and Atmospheric Administration (NOAA). The latest satellite in this lineage, NOAA-19, was launched in 2009 and continues to deliver data alongside its predecessors NOAA-15 and NOAA-18. Following their legacy, the Joint Polar Satellite System began deployment in 2011, perpetuating the mission of providing high-fidelity weather and climate data.
Earth Observing System
NASA’s Earth Observing System comprises three primary satellites: Aqua, Aura, and Terra. Each satellite focuses on distinct aspects of our planet—water, land, and atmospheric monitoring, respectively. Aqua and Aura were part of the Afternoon Constellation (A-Train), allowing multiple satellites to gather data simultaneously in a coordinated polar orbit shortly after high noon local time. This arrangement offered a comprehensive suite of observational data, essential for understanding Earth’s complex systems.
DSCOVR
Operating at the L1 Lagrange point—situated between Earth and the Sun—DSCOVR (Deep Space Climate Observatory) excels in capturing stunning full-disk images of our planet. This satellite serves not only to monitor the solar wind, providing crucial early warnings of geomagnetic storms, but also utilizes its Earth Polychromatic Imaging Camera (EPIC) to take images in ten different spectral bands every two hours. Its strategic position allows DSCOVR to observe the bright side of Earth continually, thereby enabling scientists to monitor cloud cover, vegetation, ozone levels, and atmospheric aerosols.
Although DSCOVR lacks the precision of low Earth orbit satellites, its broad observational capabilities are invaluable for assessing global environmental trends and phenomena. Notably, it has documented the Moon as it transits in front of Earth and noted the shadows cast by the Moon during solar eclipses, continuously offering a striking portrayal of our planet.
Ibuki
Ibuki, or the Greenhouse Gases Observing Satellite (GOSAT), developed by the Japan Aerospace Exploration Agency, was the pioneering satellite to specifically focus on tracking greenhouse gas emissions. Launched in response to the 1997 Kyoto Protocol, Ibuki allows for the comprehensive monitoring of carbon dioxide and methane levels globally. With its successor, Ibuki 2, launched in 2018 and still operational, the program aims to enhance our understanding of greenhouse gases and promote environmental accountability on a global scale. The upcoming Ibuki 3 promises further advancements in monitoring capabilities.
GOES East and West
The Geostationary Operational Environmental Satellite (GOES) network operates from an orbit that keeps it aligned with the Earth’s rotation, positioned 22,236 miles above the equator. The GOES-R series, including GOES East and West, represents the cutting edge of this vital satellite program, ensuring continuous monitoring of North American weather patterns. This suite of satellites has been active since 1965, with the latest iteration launching in 2016 to provide a sophisticated array of imaging and sensing capabilities.
These advanced satellites monitor not only meteorological phenomena but also contribute to the prediction of severe weather events and responses to natural disasters. Equipped to relay transponder signals during rescue operations, they play a critical role in safeguarding lives and improving disaster response efforts.
Planet
Planet Labs operates a fleet of approximately 200 satellites that deliver critical data to various sectors. These assets provide timely insights useful for industries such as agriculture, insurance, urban planning, and environmental monitoring. By filling the gaps left by governmental space agencies, Planet delivers high-resolution images and analytical data, facilitating informed decision-making for farmers forecasting crop yields, organizations tracking land usage, and businesses analyzing shipping logistics.
This innovative approach underscores the expanding role of private sector satellites in monitoring Earth’s rapidly changing environment, highlighting the vital intersection of technology and environmental stewardship.
Source
www.astronomy.com