The Advanced Along-Track Scanning Radiometer (AATSR) was one of nine instruments on board the Envisat satellite. It was the third in a series of instruments designed primarily to measure Sea Surface Temperature (SST) remotely, following on from ATSR-1 and ATSR-2 on board ERS-1 and ERS-2, respectively.

AATSR was operational from 23 July 2002 to 8 April 2012, when the Envisat mission ended.

AATSR was funded by the (then) UK’s Department of the Environment (DoE) in order to support their programme of climate prediction and research. It was developed and operated in collaboration with ESA. There was also a significant Australian contribution to the AATSR programme, which was managed by the Commonwealth Scientific and Industrial Research Organisation (CSIRO).