A Block IIA GPS satellite
Mission type Navigation
Operator US Air Force
COSPAR ID 1990-103A[1]
SATCAT № 20959[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 26 November 1990, 21:39:01 (1990-11-26T21:39:01Z) UTC
Rocket Delta II 7925-9.5,[3] D201[3]
Launch site Cape Canaveral LC-17A[3]
Orbital parameters
Reference system Geocentric
Regime Medium Earth
Perigee 20,072 kilometres (12,472 mi)[4]
Apogee 20,293 kilometres (12,609 mi)[4]
Inclination 54.9 degrees[4]
Period 717.98 minutes[4]

USA-66, also known as GPS IIA-1, GPS II-10 and GPS SVN-23, is an American navigation satellite which forms part of the Global Positioning System. It was the first of nineteen Block IIA GPS satellites to be launched, and is the oldest GPS satellite still in operation.

USA-66 was launched at 21:39:01 UTC on 26 November 1990, atop a Delta II carrier rocket, flight number D201, flying in the 7925-9.5 configuration.[3] The launch took place from Launch Complex 17A at the Cape Canaveral Air Force Station,[5] and placed USA-66 into a transfer orbit. The satellite raised itself into medium Earth orbit using a Star-37XFP apogee motor.[2]

On 30 December 1990, USA-66 was in an orbit with a perigee of 20,072 kilometres (12,472 mi), an apogee of 20,293 kilometres (12,609 mi), a period of 717.98 minutes, and 54.9 degrees of inclination to the equator.[4] It was initially given PRN 23, which it used until its retirement in February 2004, however it was subsequently reactivated broadcasting PRN 32 and in February 2008 it rejoined the operational constellation. It is located in slot 5 of plane E of the GPS constellation.[6] The satellite has a mass of 1,816 kilograms (4,004 lb). It had a design life of 7.5 years,[2] however as of 2012 it remains in service.


  1. ^ a b "Navstar 2A-01". 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.