For over a decade the ATSR series of sensors produced high quality SST data products, but the narrow swath did not encourage their use for operational tasks. This changed in 2005 when the European Space Agency's Medspiration Service introduced AATSR data in the GHRSST L2P format. This paper describes the opportunities provided by the Medspiration system for facilitating the complementary use of SST products from AATSR and from other satellite sensors. It explains how, following the implementation by Medspiration of GHRSST procedures, data products and tools, AATSR data are now being used around the world to complement the use of other sources of SST and to facilitate bias adjustments between them. Despite the limited daily coverage of AATSR its broadly reliable accuracy and stability seem to be beneficial to SST analyses that merge all available observations. The new analyses are already contributing to improved ocean and weather forecasting. This represents an unforeseen but significant role for the ATSR series, through which it continues to make an important contribution to the operational uses of SST. (C) 2011 Elsevier Inc. All rights reserved.