Envisats

Envisats, also known as ENVISAT, was the European Space Agency's flagship Earth-observing satellite. Launched in 2002 aboard an Ariane 5 rocket, it operated in a near-polar sun-synchronous orbit to monitor the Earth's environment, including atmosphere, land, and oceans. The platform was designed to function for at least five years but remained in operation for nearly a decade and a half, delivering a continuous stream of environmental data to researchers worldwide.

Envisats carried a suite of about 11 instruments for atmospheric chemistry, oceanography, hydrology, and land applications. Key payloads included ASAR, a high-resolution radar imaging instrument; MERIS, which measured ocean colour and land surface properties; AATSR, a thermal infrared radiometer; GOMOS and SCIAMACHY for atmospheric composition; MIPAS for atmospheric sounding; a radar altimeter RA-2 for sea height; DORIS for precise tracking; and a laser retroreflector for ground-based ranging. The combination enabled a broad, multi-decadal record of environmental variables.

Impact and operation: Envisats data contributed to climate research, weather prediction, ocean monitoring, and disaster assessment. It produced global datasets used by scientists, policy makers, and the public, and it helped advance methods for data fusion and long-term climate records.

End of mission: Contact with Envisats was lost on 8 April 2012, and ESA subsequently retired the mission. The satellite remains in orbit and is no longer controllable. Its legacy continues through archived data and the scientific findings derived from its instruments.

Data from Envisat are archived and accessible through ESA’s Earth Observation portals and partner archives, continuing to support research and applications. The mission established a benchmark for multi-instrument satellite monitoring of the planet and informed the design of subsequent ESA missions.