Envisat (Environmental Satellite) is the follow-on to ERS-1 and ERS-2. Devoted to environmental studies, and climate change in particular, its mission is to observe Earth's atmosphere and surface. Built by Esa, the European Space Agency, Envisat is carrying ten complementary instruments for observing parameters ranging from the marine geoid to high-resolution gaseous emissions. Among these instruments are a radar altimeter, and the DORIS orbitography and precise location system.

From 2002 to October 2010, Envisat's orbital period is 35 days, like ERS-2 and some of the ERS-1 phases. As it is integrated in new international climate study programmes such as Goos and Godae. Envisat thus forms part of the coming operational era in oceanography, offering near-real-time data access.

The RA-2 S-band module is definitively lost since 2008/01/18.

To ensure an additional 3 years lifespan, the Envisat satellite moved to a new lower orbit on October 22, 2010. From 02 November 2010, for the Envisat extension orbit, the ground track changes and consequently the repeat cycle changes: 30 days with 431 orbits per cycle instead of 35 days-501 orbits per cycle.

In April 2012, few weeks after celebrating its tenth year of service, Envisat has stopped sending data to Earth. Esa declared the end of mission for Envisat on May 9th, 2012. 

Further information on the Envisat mission web (Esa website)

Satellite  Envisat
Launch on  01/03/2002
End Date  08/06/2012
Altitude  782.4-799.8 km
Inclination  98.55°
Repetitivity  30-35 days
Agency  Esa
Goals  Observe Earth's atmosphere and surface