EOS-04 or Earth Observation Satellite - 04 (formerly known as RISAT-1A) is an Indian Space Research Organisation Radar Imaging Satellite designed to provide high-quality images under all weather conditions for applications such as Agriculture, Forestry & Plantations, Soil Moisture & Hydrology and Flood mapping.

Synthetic aperture radar can be used for Earth observation irrespective of the light and weather conditions of the area being imaged.

[6] The satellite carries a C-band synthetic-aperture radar (SAR) and has a liftoff mass of 1,710 kg (3,770 lb).

[2] The EOS-04 orbit is polar and Sun-synchronous at 06:00 AM LTDN, at approximate altitude of 529 km.

[7] Assembly Integration and Testing of spacecraft was done by a consortium led by Alpha Design Technologies Ltd.[8] Approximate cost of EOS-04 is ₹490 crore (equivalent to ₹550 crore or US$64 million in 2023).