| USA-177 | |
| Mission Type: | Navigation |
| Operator: | US Air Force |
| Cospar Id: | 2004-009A[1] |
| Satcat: | 28190 |
| Mission Duration: | 10 years (planned) |
| Spacecraft Type: | GPS Block IIR |
| Spacecraft Bus: | AS-4000 |
| Manufacturer: | Lockheed Martin |
| Launch Date: | UTC |
| Launch Rocket: | D303 |
| Launch Site: | Cape Canaveral SLC-17B |
| Orbit Reference: | Geocentric |
| Orbit Regime: | Medium Earth (Semi-synchronous) |
| Orbit Inclination: | 55 degrees |
| Orbit Period: | 718 minutes |
| Apsis: | gee |
USA-177, also known as GPS IIR-11 and GPS SVN-59, is an American navigation satellite which forms part of the Global Positioning System. It was the eleventh 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.
USA-177 was launched at 17:53:00 UTC on 20 March 2004, atop a Delta II carrier rocket, flight number D303, flying in the 7925-9.5 configuration.[2] The launch took place from Space Launch Complex 17B at the Cape Canaveral Air Force Station,[3] and placed USA-177 into a transfer orbit. The satellite raised itself into medium Earth orbit using a Star-37FM apogee motor.[4]
By 20 May 2004, USA-177 was in an orbit with a perigee of, an apogee of, a period of 718 minutes, and 55 degrees of inclination to the equator.[5] It is used to broadcast the PRN 19 signal, and operates in slot 3 of plane C of the GPS constellation. The satellite has a mass of, and a design life of 10 years.[4] As of 2012 it remains in service.