ERS

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. ERS-2 added an additional sensor for atmospheric ozone monitoring. The two satellites acquired a combined data set extending over two decades.