KaRIn, the Ka-Band Radar Interferometer of the SWOT Mission: Design and In-Flight Performance

The Surface Water and Ocean Topography (SWOT)mission was recommended by the 2007 National Research CouncilDecadal Survey to expand on previous altimetry missionslike TOPEX/Poseidon. Utilizing wide-swath altimetry technology,SWOT aims to achieve complete coverage of the world’s oceansand freshwater bodies through high-resolution elevation measurements.SWOT received approval for implementation in 2016, itwas ultimately launched in December 2022, and it is currentlydelivering preliminary data to the public. The primary instrumentin SWOT is the Ka-band Radar Interferometer (KaRIn)which utilizes JPL-developed radar interferometry technologyto measure ocean and surface water levels with unprecedentedaccuracy.This paper focuses on the challenges in designing, testing, andfinally commissioning in flight a complex instrument like KaRIn.We also present preliminary flight performance and compareit with ground measurements and simulations. Our analysisindicates that KaRIn meets or exceeds all its requirements, but ithas also revealed several interesting and unexpected observations,offering just a glimpse of future scientific discoveries that KaRInwill enable.