GFO (Geosat Follow-On)

GFO, GEOSAT Follow-On, was the US Navy’s operational radar altimeter satellite, launched 10 February 1998 from Vandenberg into the GEOSAT Exact Repeat Mission orbit, a 17-day repeat. Built to continue the 1985 GEOSAT sea surface height record, it carried a single-frequency Ku-band altimeter from Raytheon quoted near 5 cm precision, plus a water-vapor radiometer and GPS for orbit. The Navy accepted it as operational on 29 November 2000 and the mission ran until 22 October 2008. GFO fed real-time mesoscale eddy and front analysis for fleet operations, complementing the TOPEX/Poseidon and Jason reference missions.