USA-242

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
Artist's impression of a GPS IIF satellite
Mission typeNavigation
OperatorUS Air Force
COSPAR ID2013-023A
SATCAT no.39166
Mission duration12 years (planned)
Spacecraft properties
SpacecraftGPS SVN-66 (IIF-4)
Spacecraft typeGPS Block IIF
ManufacturerBoeing
Launch mass1,630 kilograms (3,590 lb)[1]
Start of mission
Launch date15 May 2013, 21:38 (2013-05-15UTC21:38Z) UTC
RocketAtlas V 401, AV-039
Launch siteCape Canaveral SLC-41
ContractorULA
Orbital parameters
Reference systemGeocentric
RegimeMedium Earth
(Semi-synchronous)
Perigee altitude20,459 kilometers (12,713 mi)[2]
Apogee altitude20,459 kilometers (12,713 mi)[2]
Inclination55 degrees[2]
Period12 hours
EpochTarget
 

USA-242 is a 1,630-kilogram (3,590 lb) 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 20,459 kilometers (12,713 mi) 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]

References

  1. Krebs, Gunter. "GPS-2F (Navstar-2F)". Gunter's Space Page. Retrieved 15 May 2013.
  2. "GPS IIF-4 Atlas V Mission Overview" (PDF). United Launch Alliance. Archived from the original (PDF) on 16 September 2013. Retrieved 15 May 2013.
  3. McDowell, Jonathan. "Issue 679 (draft)". Jonathan's Space Report. Retrieved 16 May 2013.
  4. "NANU 2013035". United States Coast Guard. Retrieved 25 June 2013.
  5. Ray, Justin. "Mission Status Center". Spaceflight Now. Retrieved 15 May 2013.
  6. Graham, William (15 May 2013). "ULA Atlas V successfully [sic] deploys new GPS satellite". NASASpaceflight.com. Retrieved 16 May 2013.
  7. "GPS Constellation Status". United States Coast Guard. Retrieved 25 June 2013.


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