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Mission typeNavigation
OperatorUS Air Force
COSPAR ID1992-009A[1]
SATCAT no.21890[1]
Mission duration7.5 years (planned)[2]
Spacecraft properties
Spacecraft typeGPS Block IIA[2]
Launch mass1,816 kilograms (4,004 lb)[2]
Start of mission
Launch date23 February 1992, 22:29:00 (1992-02-23UTC22:29Z) UTC
RocketDelta II 7925-9.5,[3] D207[3]
Launch siteCape Canaveral LC-17B[3]
End of mission
Deactivated18 December 2009 (2009-12-19)
Orbital parameters
Reference systemGeocentric
RegimeMedium Earth
Perigee altitude20,018 kilometres (12,439 mi)[4]
Apogee altitude20,343 kilometres (12,641 mi)[4]
Inclination54.7 degrees[4]
Period717.9 minutes[4]

USA-79, also known as GPS IIA-3, GPS II-12 and GPS SVN-25, was an American navigation satellite which formed part of the Global Positioning System. It was the third of nineteen Block IIA GPS satellites to be launched.

USA-79 was launched at 22:29:00 UTC on 23 February 1992, atop a Delta II carrier rocket, flight number D207, flying in the 7925-9.5 configuration.[3] The launch took place from Launch Complex 17B at the Cape Canaveral Air Force Station,[5] and placed USA-79 into a transfer orbit. The satellite raised itself into medium Earth orbit using a Star-37XFP apogee motor.[2]

On 27 March 1992, USA-79 was in an orbit with a perigee of 20,018 kilometres (12,439 mi), an apogee of 20,343 kilometres (12,641 mi), a period of 717.9 minutes, and 54.7 degrees of inclination to the equator.[4] It had PRN 25, and operated in slot 2 of plane A of the GPS constellation.[6] The satellite had a mass of 1,816 kilograms (4,004 lb). It had a design life of 7.5 years,[2] and ceased operations on 18 December 2009.


  1. ^ a b "Navstar 2A-03". US National Space Science Data Center. Retrieved 10 July 2012.
  2. ^ a b c d e f Krebs, Gunter. "GPS-2A (Navstar-2A)". Gunter's Space Page. Retrieved 10 July 2012.
  3. ^ a b c d McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 10 July 2012.
  4. ^ a b c d e McDowell, Jonathan. "Satellite Catalog". Jonathan's Space Page. Retrieved 10 July 2012.
  5. ^ McDowell, Jonathan. "Launch List". Launch Vehicle Database. Jonathan's Space Page. Retrieved 10 July 2012.
  6. ^ Wade, Mark. "Navstar". Encyclopedia Astronautica. Retrieved 10 July 2012.