| USA-242 | |
| Mission Type: | Navigation |
| Operator: | US Air Force |
| Cospar Id: | 2013-023A |
| Satcat: | 39166 |
| Mission Duration: | 12 years (planned) |
| Spacecraft: | GPS SVN-66 (IIF-4) |
| Spacecraft Type: | GPS Block IIF |
| Manufacturer: | Boeing |
| Launch Mass: | [1] |
| Launch Date: | UTC |
| Launch Rocket: | AV-039 |
| Launch Site: | Cape Canaveral SLC-41 |
| Launch Contractor: | ULA |
| Orbit Epoch: | Target |
| Orbit Reference: | Geocentric |
| Orbit Regime: | Medium Earth (Semi-synchronous) |
| Orbit Apoapsis: | 20459km (12,713miles)[2] |
| Orbit Periapsis: | 20459km (12,713miles) |
| Orbit Inclination: | 55 degrees |
| Orbit Period: | 12 hours |
| Apsis: | gee |
USA-242, also known as GPS IIF-4, GPS IIF SV-5, Navstar-68 and Vega,[3] is an American navigation satellite which was launched on 15 May 2013 and became operational on 21 June 2013.[4] The fourth Block IIF GPS satellite, it forms part of the Global Positioning System.
USA-242 is a 1630kg (3,590lb) spacecraft, built by Boeing with a design life of 15 years.[1] It operates from a semi-synchronous medium Earth orbit, at an altitude of 20459km (12,713miles) an inclination of 55 degrees,[2] in slot 5 of plane C of the GPS constellation.[5] The new satellite was originally intended to replace the seventeen-year-old USA-117 satellite,[6] but currently both USA-117 (SVN-33) and USA-242 (SVN-66) are in active use.[7] USA-242 broadcasts its navigation signals using the PRN-27 signal modulation.
United Launch Alliance conducted the launch of GPS IIF-4, using an Atlas V 401 carrier rocket. Launch took place from Space Launch Complex 41 at the Cape Canaveral Air Force Station, with liftoff occurring at 21:38 UTC on 15 May 2013, the beginning of an 18-minute launch window. The launch marked the first time since 1985 that a GPS satellite had launched on an Atlas rocket, or indeed any rocket other than a Delta.[6]