Official name GFO
Alternative name Geosat Follow-On
Cospar ID 1998-007A
Norad ID 25157
Launch date 1998-02-10
Launch site AFWTR
Launch vehicle Taurus-2210
Country/Organization USA
Type application Altimetry
Operator US Navy
RCS size LARGE
Decay date ON ORBIT
Period (min) 94.86
Inclination (deg) 108.03
Perigee (km) 425
Apogee (km) 598
Eccentricity 0.16911045943304
Mean motion (revs. per day) 15.180265654649
Semi-Major axis (km) 6889.635
Raan (deg) 69.533
Arg of perigee (deg) 129.2128
Shape Cyl + 1 Dish + 1 Pan
Mass (kg) 361.74
Diameter (m) 1
Height (m) 2.7
Span (m^2) 2.7
Lifetime 5 years planned, 10 years reached
Contractors Ball Aerospace
Equipment Radio altimeter, microwave radiometer
Propulsion ?
Configuration BCP-600 (formerly called Techstar)
Power Solar array, batteries

The US Navy GFO (Geosat Follow On), is a 369 kg minisatellite based on the Techstar platform to carry on the mission of Geosat. It was launched on the 10th February 1998 on a Taurus-2210 from VAFB alongside two Orbcomm satellites, into a 789 × 881 km (779 × 790 km planned) 108 degree inclined orbit.

The missions follows the 1985 Johns Hopkins Applied Physics lab built Geosat mission. It carries a precise radar altimeter (<5 cm) to measure small changes in sea surface heights associated with ocean circulation. The altimeter was supplied by Raytheon. A microwave radiometer is also carried supplied by AIL systems Inc. The spacecraft has 96Mbytes of on-board storage, and will generate up to 126W orbit average power. Ball Aerospace built the spacecraft, which has a contractual mission lifetime of 5 years, a mission design lifetime of 8 years. The spacecraft cost was US$ 46m and the contract was awarded in 1992.

GFO operated for nearly 11 years until 2008. A follow-on mission, GFO-2, was planned to be launched in 2014, but procurement of the satellite was deferred until 2016.

Satellite COSPAR Date LS Launch Vehicle Remarks
GFO 1998-007A 1998-02-10 AFWTR Taurus-2210 with Orbcomm FM3, FM4, Celestis 03