ESA's two European Remote Sensing (ERS) satellites, ERS-1 and ERS–2, were launched into the same orbit in 1991 and 1995 respectively. Their payloads included a synthetic aperture imaging radar, radar altimeter and instruments to measure ocean surface temperature and wind fields.

The two satellites acquired a combined data set extending over two decades.

ERS-1 carried instrumentation consisting of a core set of active microwave sensors supported by additional, complementary instruments:

  • AMI, the Active Microwave Instrument combining the functions of a Synthetic Aperture Radar (SAR) and a Wind Scatterometer. The SAR operated in image mode for the acquisition of wide-swath, all weather images over the oceans, polar regions, coastal zones and land. In wave mode the SAR produced imagettes (about 5 km x 5 km) at regular intervals for the derivation of the length and direction of ocean waves. The Wind Scatterometer used three antennae for the generation of sea surface wind speed and direction.
  • RA,  the Radar Altimeter  provided accurate measurements of sea surface elevation, significant wave heights, various ice parameters and an estimate of sea surface wind speed.
  • ATSR,  the Along Track Scanning Radiometer combining an infra-red radiometer and a microwave sounder for the measurement of sea surface temperature, cloud top temperature, cloud cover and atmospheric water vapour content.
  • PRARE, the Precise Range and Range-rate Equipment  for the accurate determination of the satellite's position and orbit characteristics, and for precise position determination (geodetic fixing).
  • LRR, Laser Retro-reflectors  for measurement of the satellite's position and orbit via the use of ground-based laser ranging stations.

 ERS-2 added an additional sensor for atmospheric ozone monitoring.  

  • GOME, the Global Ozone Monitoring Experiment, an absorption spectrometer which measured the presence of ozone, trace gases and aerosols in the stratosphere and troposphere

The ERS-1 mission ended on 10 March 2000 and ERS-2 was retired on 05 September 2011.


Credits: text is adapted from The ERS Mission on the ESA Website