Envisat (as in 'Environmental Satellite') was built over a period of ten years by the
European Space Agency (ESA), and was launched on 1 March 2002 (at 2:01 am local time) from Europe's Spaceport in
French Guiana. It is the largest satellite ever launched, and has the capacity to take simultaneous measurements using several of its ten instruments. The satellite will orbit the
Earth gathering information on all kinds of different variables, from sea temperatures to the contours of the land, in order to create a more accurate picture of the current state of the planet.
Of course, what actually happens with this information once ESA supplies it to the various committees, councils and companies that are interested still remains to be seen. There is always the possibility that upon discovering ‘Hey, global warming is really happening’, or ‘Wow… oil slicks should really be prevented’ (both likely ‘discoveries’ of the mission), this advice will simply be ignored. Still, at the very least the data will be very useful for those trying to carry out research into climate change and other environmental issues.
Below are some of the most pertinent facts about the satellite and its mission, and links to the various instruments it uses.
The satellite
- Launch: 2:01 am, 1 March, 2002, from French Guiana on an Ariane 5 launcher
- Mission length: 5 years
- Instruments: 10
- Orbit: Sun synchronous, altitude 800 km
- Inclination: 98 degrees
- Time for one orbit: 101 minutes
- Cycle (the time it takes to cover the entire planet): The complete cycle will take 35 days, but several individual instruments have shorter cycles than that, of around three days.
- Cost: About 2 billion Euros
The instruments
- GOMOS: Global Ozone Monitoring by Occultation of Stars
- SCIAMACHY: SCanning Imaging Absorption Spectrometer for Atmospheric CartograpHY
- MIPAS: Michelson interferometer for passive atmospheric sounding
- MERIS: Medium Resolution Imaging Spectrometer
- ASAR: Advanced Synthetic Aperture Radar
- AATSR: Advanced Along Track Scanning Radiometer
- RA-2: Radar Altimeter
- MWR: MicroWave Radiometer
- DORIS: Doppler Orbitography and Radio positioning Integrated by Satellite
- LRR: Laser Retro-Reflector
For more information, see http://www.esa.int