USA-94
| Names | Navstar 2A-13 GPS IIA-13 GPS II-22 GPS SVN-35 |
|---|---|
| Mission type | Navigation |
| Operator | US Air Force |
| COSPAR ID | 1993-054A[1] |
| SATCATno. | 22779 |
| Mission duration | 7.5 years (planned) 22.66 years (achieved) |
| Spacecraft properties | |
| Spacecraft | GPS IIA |
| Spacecraft type | GPS Block IIA[2] |
| Manufacturer | Rockwell International |
| Launch mass | 840 kg (1,850 lb) |
| Dimensions | 5.3 m (17 ft) of long |
| Power | 710 watts |
| Start of mission | |
| Launch date | 30 August 1993, 12:38:00UTC |
| Rocket | Delta II7925-9.5 (Delta D222) |
| Launch site | Cape Canaveral,LC-17B |
| Entered service | 1 October 1993 |
| End of mission | |
| Disposal | Graveyard orbit |
| Deactivated | 10 June 2016 |
| Orbital parameters | |
| Reference system | Geocentric orbit[3] |
| Regime | Medium Earth orbit (Semi-synchronous) |
| Slot | B4 (slot 4 plane B) |
| Perigee altitude | 20,074 km (12,473 mi) |
| Apogee altitude | 20,221 km (12,565 mi) |
| Inclination | 54.9° |
| Period | 716.0 minutes |
USA-94,also known asGPS IIA-13,GPS II-22andGPS SVN-35,was an Americannavigation satellitewhich formed part of theGlobal Positioning System.It was the thirteenth of nineteenBlock IIAGPS satellites to be launched.
Background
[edit]Global Positioning System (GPS) was developed by theU.S. Department of Defenseto provide all-weather round-the-clock navigation capabilities for military ground, sea, and air forces. Since its implementation, GPS has also become an integral asset in numerous civilian applications and industries around the globe, including recreational used (e.g., boating, aircraft, hiking), corporate vehicle fleet tracking, and surveying. GPS employs 24 spacecraft in 20,200 km circular orbits inclined at 55.0°. These vehicles are placed in 6 orbit planes with four operational satellites in each plane.[1]
GPS Block 2 was the operational system, following the demonstration system composed of Block 1 (Navstar 1 - 11) spacecraft. These spacecraft were3-axis stabilized,nadirpointing usingreaction wheels.Dual solar arrays supplied 710 watts of power. They usedS-band(SGLS) communications for control and telemetry andUltra high frequency(UHF) cross-link between spacecraft. The payload consisted of twoL-bandnavigation signals at 1575.42MHz(L1) and 1227.60 MHz (L2). Each spacecraft carried 2rubidiumand 2Cesiumclocks and nuclear detonation detection sensors. Built byRockwell Space Systemsfor the U.S. Air force, the spacecraft measured 5.3 m across with solar panels deployed and had a design life of 7.5 years.[1]
Launch
[edit]USA-94 was launched at 12:38:00 UTC on 30 August 1993, atop aDelta IIlaunch vehicle,flight number D222, flying in the 7925-9.5 configuration.[4]The launch took place fromLaunch Complex 17B(LC-17B) at theCape Canaveral Air Force Station(CCAFS),[5]and placed USA-94 into a transfer orbit. The satellite raised itself intomedium Earth orbitusing aStar-37XFPapogee motor.[2]
Mission
[edit]On 1 October 1993, USA-94 was in an orbit with aperigeeof 20,074 km (12,473 mi), anapogeeof 20,221 km (12,565 mi), aperiodof 716.0 minutes, and 54.9° ofinclinationto theequator.[3]It broadcast the PRN 5 signal, and operated in slot 4, and later 5, of plane B of the GPS constellation.[6]The satellite had a mass of 840 kg (1,850 lb) and a design life of 7.5 years.[2]It was initially decommissioned on 26 March 2009 and then kept as a residual satellite.[7]SVN 35 was then recalled to replace SVN 30 in the active constellation on 16 August 2011.[8][9]
It was then decommissioned again on 1 May 2013, after almost 20 years in orbit,[10]and finally placed in a disposal orbit approximately 1000 km above the operational constellation and deactivated on 10 June 2016.[11]
References
[edit]
This article incorporatespublic domain materialfrom websites or documents of theNational Aeronautics and Space Administration.
- ^abc"Display: Navstar 2A-13 1993-054A".NASA. 14 May 2020.Retrieved20 December2020.This article incorporates text from this source, which is in thepublic domain.
- ^abcKrebs, Gunter."GPS-2A (Navstar-2A)".Gunter's Space Page.Retrieved10 July2012.
- ^ab"Trajectory: Navstar 2A-13 1993-054A".NASA. 14 May 2020.Retrieved20 December2020.This article incorporates text from this source, which is in thepublic domain.
- ^McDowell, Jonathan."Launch Log".Jonathan's Space Report.Retrieved10 July2012.
- ^McDowell, Jonathan."Launch List".Launch Vehicle Database.Jonathan's Space Report. Archived fromthe originalon 15 August 2020.Retrieved10 July2012.
- ^Wade, Mark."Navstar".Encyclopedia Astronautica. Archived fromthe originalon 11 November 2002.Retrieved10 July2012.
- ^"NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2009023".United States Coast Guard.Retrieved23 June2016.This article incorporates text from this source, which is in thepublic domain.
- ^"NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2011062".United States Coast Guard.Retrieved23 June2016.This article incorporates text from this source, which is in thepublic domain.
- ^"2SOPS Takes Over IIF-2, Moves to Replace SVN-30 with Spare".Inside GNSS. Archived fromthe originalon 20 August 2016.Retrieved23 June2016.
- ^"NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2013027".United States Coast Guard.Retrieved3 May2013.This article incorporates text from this source, which is in thepublic domain.
- ^"Obituary: Farewell to SVN-35".United States Air Force.Retrieved23 June2016.This article incorporates text from this source, which is in thepublic domain.