EOS-04

EOS-04, also designated RISAT-1A, is ISRO's C-band synthetic aperture radar (SAR) Earth observation mission launched 14 February 2022 on PSLV-C52. The satellite operates in a sun-synchronous polar orbit at 529 km altitude, providing all-weather, day-and-night imaging capability over land.^[1]

The primary payload is a C-band SAR instrument delivering multi-mode imagery suited to agricultural monitoring, forestry assessment, soil moisture estimation, hydrological mapping, and flood detection. The sensor operates across multiple imaging modes to balance resolution and swath coverage for different application contexts.^[2] WMO OSCAR records the mission as operational with a planned decommission date of 2027-12-31.^[3]

EOS-04 continues the all-weather optical-independent monitoring capability of ISRO's RISAT programme, supporting national disaster management and natural resources applications that require image acquisition regardless of cloud cover or lighting conditions.^[1]