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]

A Block IIR GPS satellite
Mission typeNavigation
OperatorUS Air Force
COSPAR ID2001-004A[1]
SATCAT no.26690[1]
Mission duration10 years (planned)[2]
Spacecraft properties
Spacecraft typeGPS Block IIR[2]
ManufacturerLockheed Martin[2]
Launch mass2,032 kilograms (4,480 lb)[2]
Start of mission
Launch date30 January 2001, 07:55:01 (2001-01-30UTC07:55:01Z) UTC
RocketDelta II 7925-9.5, D283[3]
Launch siteCape Canaveral SLC-17A[3]
Orbital parameters
Reference systemGeocentric
RegimeMedium Earth
Perigee altitude20,104 kilometres (12,492 mi)[4]
Apogee altitude20,266 kilometres (12,593 mi)[4]
Inclination55 degrees[4]
Period718.08 minutes[4]

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] The satellite was retired in 2018.


  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. Archived from the original on November 11, 2002. Retrieved 11 July 2012.