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A Block IIR GPS satellite
Mission type Navigation
Operator US Air Force
COSPAR ID 2001-004A[1]
SATCAT no. 26690[1]
Mission duration 10 years (planned)[2]
Spacecraft properties
Spacecraft type GPS Block IIR[2]
Bus AS-4000[2]
Manufacturer Lockheed Martin[2]
Launch mass 2,032 kilograms (4,480 lb)[2]
Start of mission
Launch date 30 January 2001, 07:55:01 (2001-01-30UTC07:55:01Z) UTC
Rocket Delta II 7925-9.5, D283[3]
Launch site Cape Canaveral SLC-17A[3]
Orbital parameters
Reference system Geocentric
Regime Medium Earth
Perigee 20,104 kilometres (12,492 mi)[4]
Apogee 20,266 kilometres (12,593 mi)[4]
Inclination 55 degrees[4]
Period 718.08 minutes[4]

USA-156, also known as GPS IIR-7 and GPS SVN-54, is an American navigation satellite which forms part of the Global Positioning System. It was the seventh Block IIR GPS satellite to be launched, out of thirteen in the original configuration, and twenty one overall. It was built by Lockheed Martin, using the AS-4000 satellite bus.[2]

USA-156 was launched at 07:55:01 UTC on 30 January 2001, atop a Delta II carrier rocket, flight number D283, flying in the 7925-9.5 configuration.[3] The launch took place from Space Launch Complex 17A at the Cape Canaveral Air Force Station,[5] and placed USA-156 into a transfer orbit. The satellite raised itself into medium Earth orbit using a Star-37FM apogee motor.[2]

By 2 February 2001, USA-156 was in an orbit with a perigee of 20,104 kilometres (12,492 mi), an apogee of 20,266 kilometres (12,593 mi), a period of 718.08 minutes, and 55 degrees of inclination to the equator.[4] It is used to broadcast the PRN 18 signal, and operates in slot 4 of plane E of the GPS constellation.[6] The satellite has a mass of 2,032 kilograms (4,480 lb), and a design life of 10 years.[2] As of 2012 it remains in service.


  1. ^ a b "Navstar 50". US National Space Science Data Center. Retrieved 11 July 2012. 
  2. ^ a b c d e f g h Krebs, Gunter. "GPS-2R (Navstar-2R)". Gunter's Space Page. Retrieved 11 July 2012. 
  3. ^ a b c McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 11 July 2012. 
  4. ^ a b c d e McDowell, Jonathan. "Satellite Catalog". Jonathan's Space Page. Retrieved 11 July 2012. 
  5. ^ McDowell, Jonathan. "Launch List". Launch Vehicle Database. Jonathan's Space Page. Retrieved 11 July 2012. 
  6. ^ Wade, Mark. "Navstar". Encyclopedia Astronautica. Retrieved 11 July 2012.