Earth observation satellites are Earth-orbiting spacecraft with sensors used to collect imagery and measurements of the surface of the earth. These satellites are used to monitor short-term weather, long-term climate change, natural disasters. Earth observations satellites provide information for research subjects that benefit from looking at Earth’s surface from above (such as meteorology, oceanography, terrestrial ecology, glaciology, atmospheric science, hydrology, geology, and many more). Types of sensors on these satellites include passive and active remote sensors. Sensors on Earth observation satellites often take measurements of emitted energy over some portion of the electromagnetic spectrum (e.g., UV, visible, infrared, microwave, or radio).[1]
The invention of climate research through the use of satellite remote telemetry began in the 1960s through development of space probes to study other planets. During the U.S. economic decline in 1977, with much of NASA's money going toward the shuttle program, the Reagan Administration proposed to reduce spending on planetary exploration. During this time, new scientific evidence emerged from ice and sediment cores that Earth's climate had experienced rapid changes in temperature, running contrary to the previously held belief that the climate changed on a geological time scale. These changes increased political interest in gathering remote-sensing data on the Earth itself and stimulated the science of climatology.[2]
Classification
The lists below classify Earth observation satellites in two large groups: satellites operated by government agencies of one or more countries (public domain) versus commercial satellites built and maintained by companies (private domain).[3] These lists focus on currently active missions, rather than inactive retired missions or planned future missions. However, some examples of past and future satellites are included. Active, inactive, or planned classifications are relevant as of 2021.
Used for defense and security assurance in Italy and other countries, seismic hazard analysis, environmental disaster monitoring, and agricultural mapping.
Translated from Chinese, the word Fengyun means "wind cloud." Series 3 satellites are Sun-synchronous and series 2 and 4 satellites are geosynchronous.
Used for mapping and planning, landcover survey, geology, ecosystem monitoring, disaster management, environmental control, coastal zone management, and water resources.
Used for mapping and planning, landcover survey, geology, ecosystem monitoring, disaster management, environmental control, coastal zone management, and water resources.[10]
Gravity and climate. The mission will track changes in global sea levels, glaciers, and ice sheets, as well as large lake and river water levels, and soil moisture.[15]
Follow on to Landsat-8 with OLI sensor and thermal sensor TIRS-2. Landsat-9 will extend the Landsat program to maintain the time series of these type of data.
Plankton, Aerosol, Cloud, and ocean Ecosystem measures hyperspectral and polarimetric characteristics of solar radiation reflected off Earth’s surface and atmosphere.
Constellation of two, each satellite carries sensors OLCI and SLSTR. Slightly coarser spatial resolution and more spectral bands than Sentinel-2. Part of the Copernicus Programme.
Continuing the legacy of the Jason series missions, Sentinel-6/Jason-CS will extend the records of sea level (sea surface height) and provide information for operational oceanography, marine meteorology, and climate studies.[21]
Soil Moisture Active Passive. Measures soil moisture and its freeze/thaw state, which enhance understanding of processes that link water, energy, and carbon cycles to extend the capabilities of weather and climate models. Radar payload failed in July 2015, leaving a radiometer as the primary instrument of the mission.[22]
Carries five instruments to observe the state of the atmosphere, land, and oceans, as well as their interactions with solar radiation and with one another.[23]
Gravity Recovery And Climate Experiment. Tracked changes in global sea levels, glaciers, and ice sheets, as well as large lake and river water levels, and soil moisture.[31] Retired 2017.[32]
Carried the Aquarius instrument, which measured ocean salinity (salt concentration) which improves knowledge of heat transport and storage in the ocean.[1] Mission ended June 2015 due to satellite power supply failure.[38]
Far-infrared Outgoing Radiation Understanding and Monitoring; a mission to measure Earth's outgoing radiation emissions across the entire far-infrared electromagnetic spectrum.
^ abcdeFor constellations of multiple satellites, launch year is listed here as the maiden launch year for the first satellite in the series.[4]
References
^Emery, William (2017). Introduction to satellite remote sensing : atmosphere, ocean, land and cryosphere applications. Amsterdam: Elsevier. ISBN978-0-12-809259-0. OCLC1002847813.