(U) Geodetic/Geo-Physical Satellite Follow-on (GFO)

(The effects of any budget/program decisions made since the information was collected during 1997-98 are NOT reflected in the National Security Space Road Map (NSSRM).)

Overview: (U)
(U) The U. S. Navy through their meteorological and oceanographic (METOC) program operates the Geodetic/Geophysical (GEOSAT) Follow-On (GFO) program to provide critical oceanographic data to ships at sea and to oceanographic modeling centers. 

Description: (U)
(U)  The GEOSAT Follow-on (GFO) will include all the capabilities necessary for the precise measurement of both mesoscale and basin-scale oceanography. The spacecraft will add a water vapor radiometer and GPS receiver to the basic GEOSAT measurement capability. GFO is to be launched aboard an TAURUS launch vehicle from Vandenberg Air Force Base in California on 4 Nov1997. During the 10 year mission life, the satellite will be in the GEOSAT Exact Repeat Mission (ERM) orbit (800 km altitude, 108 deg inclination, 0.001 eccentricity, and, 100 min period). This 17-day Exact Repeat Orbit (ERO) will retrace the ERM ground track to +/-1 km. As with the GEOSAT ERM, the data will be available for ocean science through NOAA/NOS and NOAA/NESDIS. The 300-kg spacecraft is approximately 3-m long and supports the following payload: 

- (U) 1.  Radar Altimeter - single frequency (13.5 GHz) with 3.5-cm height precision. 
- (U)  2.  Water Vapor Radiometer - dual frequency (22 and 37 GHz) nadir-looking with a path correction accuracy of 1.9 cm rms. 
- (U)  3.  GPS Receivers - redundant receivers allow precision orbit determination with an rms accuracy in the radial component of 10 cm on wavelengths less than 40,000 km. 
- (U)  4. Doppler Beacon - GEOSAT performance-stable oscillators and doppler beacons will allow operational orbits to be determined with 1.8-cm rms radial orbit error for mesoscale oceanography (after tilt and bias removal) along a 3000-km arc-filter length. 

(U)  The payload will feature complete redundancy, light weight (47 kg total), and low power consumption (121 W total).  All payload data will be provided on an encrypted, continuously operating tactical downlink to AN/SMQ11-equipped Navy ships and facilities. Sea surface topography derived from the altimeter data will be used for tactical environmental aids and for boundary conditions for shipboard ocean model. Also, payload data will be dumped approximately every 12 hours and sent to the NAVOCEANO Altimeter Data Fusion Center (ADFC) at Stennis Space Center, Mississippi for processing. 

(U)  The GFO Ground Segment will include two NAVSOC remote tracking sites at Prospect Harbor, Maine, and Pt. Mugu, California. Satellite payload and engineering data will be relayed to the Satellite Operations Center (SOC) at NAVSOC Headquarters with payload data sent directly to the Payload Operations Center (POC) at NAVOCEANO. The SOC will provide all system and satellite operations with remote commanding via the remote sites. 

User Impact: (U)
(U) To be supplied.

Programmatics: (U)
(U) Operational.
	(U) IOC: 05/1997 (3QFY1997).

(U) Organizations and Funding:
	(U) Navy.

Related Initiatives: (U)
(U) GEOSAT, Taurus, Western Range

Related Requirements: (U)
(U) None.

Related Categories: (U)
(U) Space Systems

Road Map Placements: (U)
(U) ENVIRONMENTAL MONITORING.

Lead Office: (U)
(U) Navy.

Date of Information: (U)
07 August 1997

(The effects of any budget/program decisions made since the information was collected during 1997-98 are NOT reflected in the National Security Space Road Map (NSSRM).)