ATSR-1 was the first of the ATSR Sensors. It was conceived by a group of UK scientists in 1981, accepted as an announcement of opportunity package by ESA in 1982 and launched on-board ERS-1 on 17 July 1991. The experimental instrument was supported financially by the UK's Science and Engineering Research Council (SERC) with additional contributions from Australia.
The along-track scanning radiometer was conceived and developed by a consortium of academic and research institutes, including the University of Oxford Department of Atmospheric Physics, where much of the early idea for the instrument had originated and where the completed instrument was calibrated prior to its launch; the UK Met Office, who developed and built the ATSR focal plane assembly; University College London´s Mullard Space Science Laboratory, who designed and developed the crucial high-performance and exceptionally stable on-board blackbody reference targets; and by the Rutherford Appleton Laboratory, who led the consortium and designed, built and delivered ATSR-1 to ESA.
The instrument was developed in response to the need, which was increasingly being expressed by the climate community, for accurate global measurements of sea surface temperature (SST), preferably with accuracies of better than 0.3°C. At that time, satellites were achieving SST accuracies of around 0.5°C, which, although a considerable achievement, was proving inadequate for the demanding requirements of climate research.
ATSR-1 was the first instrument to implement an along-track scanning viewing geometry in order to produce a superior atmospheric correction, the first to use a two-reference target on-board calibration system to produce an exceptionally stable on-board calibration scheme and it carried the first sterling-cycle cooler of its kind in space, which enabled the detectors to achieve and maintain their optimum operating temperatures. These were all important scientific and technical attributes which are still the defining features of the ATSR sensors.
ATSR-1 in the clean room at RAL
ERS-1 was launched shortly after the major eruption of Mount Pinatubo, which had injected large quantities of volcanic ash into the atmosphere. This meant that ATSR data could not be validated in normal atmospheric conditions. Nevertheless, as soon as it was commissioned, it began to produce measurements of SST (albeit not validated) at a time when single-view infrared sensors were unable to retrieve SST.
ATSR-1 successfully demonstrated the technology (dual-view, continuous on-board calibration and low noise detectors cooled by Sterling cycle coolers) that now delivers the most accurate SST measurements available from space-borne instruments.
More information on ATSR-1 can be found on the following websites: ATSR-1 and ATSR-2 (RAL website)ATSR-1 and ATSR-2 (ESA website)
Click to move to ATSR-2 or AATSR or SLSTR.