SARAL is a joint India–France satellite that measures sea surface height with a Ka-band radar altimeter. PSLV-C20 launched it in February 2013.
SARAL measures the height of the sea surface to study how the ocean circulates. Its main instrument, AltiKa, is a radar altimeter built by the French space agency CNES that works at 35.75 GHz in the Ka band. The data helps marine weather and sea-state forecasts, climate monitoring and ice studies.
CNES also supplied an ARGOS data-collection system, which gathers readings from ocean buoys and passes them to ground stations. ISRO added a C-band transponder used to calibrate ground radars.
ISRO built the satellite on its small Indian Mini Satellite-2 platform. SARAL weighed 407 kg at lift-off and makes 906 W from its solar array. It flies in a sun-synchronous polar orbit about 781 km up, crossing the equator at 6 pm.
PSLV-C20, the twenty-third PSLV flight, launched SARAL from the First Launch Pad at Sriharikota on 25 February 2013. Six small satellites from Canada, Austria, Denmark and the UK flew with it. The rocket used its lighter core-alone version, with no strap-on boosters.
SARAL was designed for five years. The public satellite catalogue carries SARAL with an operational flag.