EOS-04, also known as RISAT-1A, is an Indian radar imaging satellite launched on PSLV-C52 in February 2022. Its radar can take pictures by day or night and in any weather.
EOS-04's main instrument is an active C-band synthetic aperture radar. It lights up the ground with its own microwave signal, so it does not need sunlight. ISRO designed it to return high-quality images in all weather conditions.
ISRO lists its main uses as agriculture, forestry and plantations, soil moisture and hydrology, and flood mapping. Gunter's Space Page lists it as RISAT-1A, a copy of RISAT-1 (launched in 2012) meant to continue that satellite's radar service.
EOS-04 was built at the U R Rao Satellite Centre in Bengaluru. It weighs about 1,710 kg, generates 2,280 W of power and was designed for a mission life of 10 years.
PSLV-C52 lifted off from the first launch pad at Sriharikota at 05:59 IST on 14 February 2022. At 06:17 IST it placed EOS-04 in a sun-synchronous polar orbit at 529 km altitude.
It was the 54th flight of PSLV and the 23rd in the XL configuration, which has six strap-on motors. Two small satellites rode along: the student satellite INSPIREsat-1 and ISRO's technology demonstrator INS-2TD.
The public satellite catalogue carries EOS-04 with an operational flag.