USA-126
| Names | Navstar 2A-17 GPS IIA-17 GPS II-26 GPS SVN-40 |
|---|---|
| Mission type | Navigation |
| Operator | U.S. Air Force |
| COSPAR ID | 1996-041A[1] |
| SATCATno. | 23953 |
| Mission duration | 7.5 years (planned) 19.5 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 | 16 July 1996, 00:50:00UTC |
| Rocket | Delta II7925-9.5 (Delta D237) |
| Launch site | Cape Canaveral,LC-17A |
| Entered service | 15 August 1996 |
| End of mission | |
| Disposal | Graveyard orbit |
| Deactivated | 11 March 2016 |
| Orbital parameters | |
| Reference system | Geocentric orbit[3] |
| Regime | Medium Earth orbit (Semi-synchronous) |
| Slot | E3 (slot 3 plane E) |
| Perigee altitude | 20,272 km (12,596 mi) |
| Apogee altitude | 20,365 km (12,654 mi) |
| Inclination | 55.03° |
| Period | 723.60 minutes |
USA-126,also known asGPS IIA-17,GPS II-26andGPS SVN-40,is an Americannavigation satellitewhich forms part of theGlobal Positioning System.It was the seventeenth 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-126 was launched at 00:50:00 UTC on 16 July 1996, atop aDelta IIlaunch vehicle,flight number D237, flying in the 7925-9.5 configuration.[4]The launch took place fromLaunch Complex 17A(LC-17A) at theCape Canaveral Air Force Station(CCAFS),[5]and placed USA-126 into a transfer orbit. The satellite raised itself intomedium Earth orbitusing aStar-37XFPapogee motor.[2]
Mission[edit]
On 15 August 1996, USA-126 was in an orbit with aperigeeof 20,272 km (12,596 mi), anapogeeof 20,365 km (12,654 mi), aperiodof 723.60 minutes, and 55.03° ofinclinationto theequator.[3]It broadcasts the PRN 10 signal, and operates in slot 3 of plane E of the GPS constellation.[6]The satellite has a mass of 840 kg (1,850 lb). It had a design life of 7.5 years,[2]however, it was kept in service for over 18 years before finally decommissioned from service on 16 July 2015.[7]
Following decommissioning, it was subsequently placed in a disposal orbit approximately 1000 km above the operational constellation on 11 March 2016.[8]
References[edit]
- ^abc"Display: Navstar 2A-17 1996-041A".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-17 1996-041A".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.Retrieved11 July2012.
- ^McDowell, Jonathan."Launch List".Launch Vehicle Database.Jonathan's Space Report.Retrieved11 July2012.
- ^Wade, Mark."Navstar".Encyclopedia Astronautica. Archived fromthe originalon 11 November 2002.Retrieved10 July2012.
- ^"NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2015069".United States Coast Guard.Retrieved21 March2016.This article incorporates text from this source, which is in thepublic domain.
- ^"50 SW to dispose of two GPS satellites".United States Air Force.Retrieved21 March2016.This article incorporates text from this source, which is in thepublic domain.