USA-71

USA-71
Mission type Navigation
Operator US Air Force
COSPAR ID 1991-047A[1]
SATCAT no. 21552[1]
Mission duration 7.5 years (planned)[2]
Spacecraft properties
Spacecraft type GPS Block IIA[2]
Manufacturer Rockwell[2]
Launch mass 1,816 kilograms (4,004 lb)[2]
Start of mission
Launch date 4 July 1991, 02:32:00 (1991-07-04UTC02:32Z) UTC
Rocket Delta II 7925-9.5,[3] D206[3]
Launch site Cape Canaveral LC-17A[3]
Orbital parameters
Reference system Geocentric
Regime Medium Earth
(Semi-synchronous)
Perigee 20,085 kilometres (12,480 mi)[4]
Apogee 20,274 kilometres (12,598 mi)[4]
Inclination 55.1 degrees[4]
Period 717.86 minutes[4]

USA-71, also known as GPS IIA-2, GPS II-11 and GPS SVN-24, is an American navigation satellite which forms part of the Global Positioning System. It was the second of nineteen Block IIA GPS satellites to be launched.

USA-71 was launched at 02:32:00 UTC on 4 July 1991, atop a Delta II carrier rocket, flight number D206, flying in the 7925-9.5 configuration.[3] The rocket launched from Launch Complex 17A at the Cape Canaveral Air Force Station,[5] and placed USA-71 into a transfer orbit. The satellite raised itself into medium Earth orbit using a Star-37XFP apogee motor.[2]

On 14 August 1991, USA-71 was in an orbit with a perigee of 20,085 kilometres (12,480 mi), an apogee of 20,274 kilometres (12,598 mi), a period of 717.86 minutes, and 55.1 degrees of inclination to the equator.[4] It has PRN 24, and operated in slot 1 of plane D of the GPS constellation[6] until it was removed from service in September 2009. It was subsequently relocated, was operational again, briefly covering slot 2 in 2011, before being deactivated in November after USA-232 replaced it. It began transmitting navigation signals again in March 2012; however, it is not currently part of the operational GPS constellation.[7] The satellite has a mass of 1,816 kilograms (4,004 lb), and a design life of 7.5 years.[2]

References

  1. 1 2 "Navstar 2A-02". US National Space Science Data Center. Retrieved 10 July 2012.
  2. 1 2 3 4 5 6 Krebs, Gunter. "GPS-2A (Navstar-2A)". Gunter's Space Page. Retrieved 10 July 2012.
  3. 1 2 3 4 McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 10 July 2012.
  4. 1 2 3 4 5 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.
  7. ↑ "NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2012018". US Air Force. Retrieved 10 July 2012.


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