An Earth observation satellite or Earth remote sensing satellite is a satellite used or designed for Earth observation (EO) from orbit, including spy satellites and similar ones intended for non-military uses such as environmental monitoring, meteorology, cartography and others. The most common type are Earth imaging satellites, that take satellite images, analogous to aerial photographs; some EO satellites may perform remote sensing without forming pictures, such as in GNSS radio occultation.
RADARSAT-1 was Canada's first commercial Earth observation satellite. It utilized synthetic aperture radar (SAR) to obtain images of the Earth's surface to manage natural resources and monitor global climate change. As of March 2013, the satellite was declared non-operational and is no longer collecting data.
European Remote Sensing satellite (ERS) was the European Space Agency's first Earth-observing satellite programme using a polar orbit. It consisted of two satellites, ERS-1 and ERS-2, with ERS-1 being launched in 1991.
Satellite geodesy is geodesy by means of artificial satellites—the measurement of the form and dimensions of Earth, the location of objects on its surface and the figure of the Earth's gravity field by means of artificial satellite techniques. It belongs to the broader field of space geodesy. Traditional astronomical geodesy is not commonly considered a part of satellite geodesy, although there is considerable overlap between the techniques.
Space-based radar or spaceborne radar is a radar operating in outer space; orbiting radar is a radar in orbit and Earth orbiting radar is a radar in geocentric orbit. A number of Earth-observing satellites, such as RADARSAT, have employed synthetic aperture radar (SAR) to obtain terrain and land-cover information about the Earth.
A scatterometer or diffusionmeter is a scientific instrument to measure the return of a beam of light or radar waves scattered by diffusion in a medium such as air. Diffusionmeters using visible light are found in airports or along roads to measure horizontal visibility. Radar scatterometers use radio or microwaves to determine the normalized radar cross section of a surface. They are often mounted on weather satellites to find wind speed and direction, and are used in industries to analyze the roughness of surfaces.
The NASA QuikSCAT was an Earth observation satellite carrying the SeaWinds scatterometer. Its primary mission was to measure the surface wind speed and direction over the ice-free global oceans via its effect on water waves. Observations from QuikSCAT had a wide array of applications, and contributed to climatological studies, weather forecasting, meteorology, oceanographic research, marine safety, commercial fishing, tracking large icebergs, and studies of land and sea ice, among others. This SeaWinds scatterometer is referred to as the QuikSCAT scatterometer to distinguish it from the nearly identical SeaWinds scatterometer flown on the ADEOS-2 satellite.
Fuk K. Li is the Director of the Mars Exploration Directorate at NASA's Jet Propulsion Laboratory.
TerraSAR-X, is an imaging radar Earth observation satellite, a joint venture being carried out under a public-private-partnership between the German Aerospace Center (DLR) and EADS Astrium. The exclusive commercial exploitation rights are held by the geo-information service provider Astrium. TerraSAR-X was launched on 15 June 2007 and has been in operational service since January 2008. With its twin satellite TanDEM-X, launched 21 June 2010, TerraSAR-X acquires the data basis for the WorldDEM, the worldwide and homogeneous DEM available from 2014.
Sentinel-3 is an Earth observation heavy satellite series developed by the European Space Agency as part of the Copernicus Programme. As of 2024, it consists of 2 satellites: Sentinel-3A and Sentinel-3B. After initial commissioning, each satellite was handed over to EUMETSAT for the routine operations phase of the mission. Two recurrent satellites, Sentinel-3C and Sentinel-3D, will follow in approximately 2025 and 2028 respectively to ensure continuity of the Sentinel-3 mission.
Soil Moisture Active Passive (SMAP) is a NASA environmental monitoring satellite that measures soil moisture across the planet. It is designed to collect a global 'snapshot' of soil moisture every 2 to 3 days. With this frequency, changes from specific storms can be measured while also assessing impacts across seasons of the year. SMAP was launched on 31 January 2015. It was one of the first Earth observation satellites developed by NASA in response to the National Research Council's Decadal Survey.
The Spaceborne Imaging Radar (SIR) – full name 'Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR)', is a synthetic aperture radar which flew on two separate shuttle missions. Once from the Space Shuttle Endeavour in April 1994 on (STS-59) and again in October 1994 on (STS-68). The radar was run by NASA's Space Radar Laboratory. SIR utilizes 3 radar frequencies: L band, C band (6 cm) and X band (3 cm), allowing for study of geology, hydrology, ecology and oceanography. Comparing radar images to data collected by teams of people on the ground as well as aircraft and ships using simultaneous measurements of vegetation, soil moisture, sea state, snow and weather conditions during each flight. The imaging radar was able to take images anytime regardless of clouds cover. The Radar-C system was built and operated by NASA's Jet Propulsion Laboratory (JPL). The mission was a joint work of NASA with the German and Italian space agencies. Each of the week long mission scanned about 50 million square kilometers of the Earth's surface,.
ADEOS I was an Earth observation satellite launched by NASDA in 1996. The mission's Japanese name, Midori means "green". The mission ended in July 1997 after the satellite sustained structural damage to the solar panel. Its successor, ADEOS II, was launched in 2002. Like the first mission, it ended after less than a year, also following solar panel malfunctions.
The Alaska Satellite Facility (ASF) is a data processing facility and satellite-tracking ground station within the Geophysical Institute at the University of Alaska Fairbanks. The facility’s mission is to make remote-sensing data accessible Its work is central to polar processes research including wetlands, glaciers, sea ice, climate change, permafrost, flooding and land cover such as changes in the Amazon rainforest.
The NASA-ISRO Synthetic Aperture Radar (NISAR) mission is a joint project between NASA and ISRO to co-develop and launch a dual-frequency synthetic aperture radar on an Earth observation satellite. The satellite will be the first radar imaging satellite to use dual frequencies. It will be used for remote sensing, to observe and understand natural processes on Earth. For example, its left-facing instruments will study the Antarctic cryosphere. With a total cost estimated at US$1.5 billion, NISAR is likely to be the world's most expensive Earth-imaging satellite.
George Henry Born was an American aerospace engineer, Distinguished Professor, founder and Director Emeritus of the Colorado Center for Astrodynamics Research (CCAR) at the University of Colorado Boulder. He is known for his work in satellite navigation and precise orbit determination. He worked on various missions while at the Jet Propulsion Laboratory as well as navigation support for the Apollo program in the late 1960s while at Johnson Space Center.
EnVision is an orbital mission to Venus being developed by the European Space Agency (ESA) that is planned to perform high-resolution radar mapping and atmospheric studies. EnVision is designed to help scientists understand the relationships between its geological activity and the atmosphere, and it would investigate why Venus and Earth took such different evolutionary paths. The probe was selected as the fifth medium mission (M5) of ESA's Cosmic Vision programme in June 2021, with launch planned for 2031. The mission will be conducted in collaboration with NASA, with the potential sharing of responsibilities currently under assessment.
Diane L. Evans is a geologist and the former Director of Earth Science and Technology Directorate at NASA's Jet Propulsion Laboratory. Her research areas have included sea-level rise, climate change, and tectonics. In 2019, she was recognized by Congressman Adam Schiff for her contributions in his district.
Eni G. Njoku is a Nigerian-American scientist specializing in microwave remote sensing. He worked at the Jet Propulsion Laboratory (JPL), California Institute of Technology, where he was responsible for developing techniques for sea surface temperature and soil moisture remote sensing using microwave radiometers. He produced the first microwave-derived sea surface temperature maps from space, and developed the first application of deployable mesh antennas for satellite Earth observation. From 2008-2013, he served as project scientist of NASA's first soil moisture mission, the Soil Moisture Active Passive (SMAP) mission, launched in 2015.
The history of synthetic-aperture radar begins in 1951, with the invention of the technology by mathematician Carl A. Wiley, and its development in the following decade. Initially developed for military use, the technology has since been applied in the field of planetary science.
