NISAR

NISAR (NASA-ISRO Synthetic Aperture Radar) is a joint Earth observation mission developed by NASA and the Indian Space Research Organisation (ISRO), launched on 30 July 2025 by GSLV-F16. The satellite operates in a sun-synchronous orbit at 747 km altitude (98.4 degree inclination) with a 12-day exact repeat cycle and 6-day effective revisit, covering a 242 km swath. NISAR carries dual-frequency synthetic aperture radar instruments: an L-band SAR (approximately 24 cm wavelength, contributed by NASA) and an S-band SAR (approximately 9.4 cm wavelength, contributed by ISRO), both using a SweepSAR wide-swath architecture. ISRO announced the mission's entry into science phase in November 2025, and NASA reports the science phase beginning in early January 2026. The mission supports surface deformation mapping via interferometric SAR, surface backscatter analysis, and full-polarimetric SAR decomposition for land cover, ecosystem, and cryosphere studies. Primary acquisitions target global land and ice surfaces, with S-band observations concentrated over India and calibration sites. ^[1][2][3][4]