|Operator||US Air Force|
|Mission duration||7.5 years (planned)|
|Spacecraft type||GPS Block IIA|
|Launch mass||1,816 kilograms (4,004 lb)|
|Start of mission|
|Launch date||23 February 1992, 22:29:00UTC|
|Rocket||Delta II 7925-9.5, D207|
|Launch site||Cape Canaveral LC-17B|
|End of mission|
|Deactivated||18 December 2009|
|Perigee altitude||20,018 kilometres (12,439 mi)|
|Apogee altitude||20,343 kilometres (12,641 mi)|
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. The launch took place from Launch Complex 17B at the Cape Canaveral Air Force Station, and placed USA-79 into a transfer orbit. The satellite raised itself into medium Earth orbit using a Star-37XFP apogee motor.
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. It had PRN 25, and operated in slot 2 of plane A of the GPS constellation. The satellite had a mass of 1,816 kilograms (4,004 lb). It had a design life of 7.5 years, and ceased operations on 18 December 2009.
- "Navstar 2A-03". US National Space Science Data Center. Retrieved 10 July 2012.
- Krebs, Gunter. "GPS-2A (Navstar-2A)". Gunter's Space Page. Retrieved 10 July 2012.
- McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 10 July 2012.
- McDowell, Jonathan. "Satellite Catalog". Jonathan's Space Page. Retrieved 10 July 2012.
- McDowell, Jonathan. "Launch List". Launch Vehicle Database. Jonathan's Space Page. Retrieved 10 July 2012.
- Wade, Mark. "Navstar". Encyclopedia Astronautica. Retrieved 10 July 2012.
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