Envisat

The largest and most powerful Earth observation satellite ever built by the European Space Agency; it is a successor to ESA's ERS remote sensing satellites ERS-1 and ERS-2. Envisat was launched on Mar. 1, 2002 aboard an Ariane 5 into a sun-synchronous orbit at a height of 790 km (±10 km). It orbits the Earth in about 101 minutes with a repeat cycle of 35 days. Envisat carries an array of nine Earth-observation instruments that gather information about the Earth (land, water, ice, and atmosphere):

ASAR (Advanced Synthetic Aperture Radar) can detect changes in surface heights with sub-millimeter precision
MERIS (MEdium Resolution Imaging Spectrometer) produces two-dimensional images using a 15-band spectrometer
AATSR (Advanced Along Track Scanning Radiometer) can measure the temperature of the sea surface
RA-2 (Radar Altimeter 2) is a dual-frequency nadir pointing radar operating in the S band and Ku bands, used for measuring ocean topography, map/monitor sea ice and measure land heights
MWR (Microwave Radiometer) for measuring water vapor in the atmosphere and give corrections for the altimeter
DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) for orbit determination to within 10 cm or less
GOMOS (Global Ozone Monitoring by Occultation of Stars) looks to stars as they descend through the Earth's atmosphere and change color, which also tells a lot about the presence of gases such as ozone, and allows for the first time a space-based measurement of the vertical distribution of these trace gases
MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) is a spectrometer
SCIAMACHY (SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY) compares light coming from the Sun to light reflected by the Earth, which provides information on the atmosphere through which the earth-reflected light has passed

External site

Envisat home page

Related category

• SATELLITES AND SPACE PROBES

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Encyclopedia of Alternative Energy & Sustainable Living
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