OPS 5112
| Names | Navstar 2 NDS-2 GPS I-2 GPS SVN-2 |
|---|---|
| Mission type | Navigation Technology |
| Operator | U.S. Air Force |
| COSPAR ID | 1978-047A[1] |
| SATCATno. | 10893 |
| Mission duration | 5 years (planned) 3 years (achieved) |
| Spacecraft properties | |
| Spacecraft | Navstar |
| Spacecraft type | GPS Block I |
| Manufacturer | Rockwell Space Systems[2] |
| Launch mass | 758 kg (1,671 lb) |
| Dimensions | 5.3 meters of long |
| Power | 400 watts |
| Start of mission | |
| Launch date | 13 May 1978, 10:34:00 UTC |
| Rocket | Atlas F/ SGS-1 (Atlas-49F)[3] |
| Launch site | Vandenberg,SLC-3E |
| Contractor | Convair General Dynamics |
| Entered service | 14 July 1978 |
| End of mission | |
| Deactivated | 16 July 1981 |
| Orbital parameters | |
| Reference system | Geocentric orbit[4] |
| Regime | Medium Earth orbit (Semi-synchronous) |
| Perigee altitude | 19,952 km (12,398 mi) |
| Apogee altitude | 20,084 km (12,480 mi) |
| Inclination | 63.10° |
| Period | 711.30 minutes |
OPS 5112,also known asNavstar 2,NDS-2,GPS I-2andGPS SVN-2,was an Americannavigation satellitelaunched in 1978 as part of theGlobal Positioning Systemdevelopment programme. It was the second of elevenBlock IGPS satellites to be launched.[2]
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°. These vehicles are placed in 6 orbit planes with four operational satellites in each plane.[1]
Spacecraft
[edit]The first eleven spacecraft (GPS Block 1) were used to demonstrate the feasibility of the GPS system. They were 3-axis stabilized, nadir pointing usingreaction wheels.Dual solar arrays supplied over 400 W. They had S-band (SGLS) communications for control and telemetry and UHF cross-link between spacecraft. They were manufactured by Rockwell Space Systems, were 5.3 m across with solar panels deployed, and had a design life expectancy of 5 years. Unlike the later operational satellites, GPS Block 1 spacecraft were inclined at 63°.[1]
Launch
[edit]OPS 5112 was launched at 10:34 UTC on 13 May 1978, atop anAtlas Flaunch vehiclewith an SGS-1upper stage.The Atlas used had the serial number 49F, and was originally built as an Atlas F.[3]The launch took place fromVandenberg Space Launch Complex 3(SLC-3E) atVandenberg Air Force Base,[5]and placed OPS 5112 into a transfer orbit. The satellite raised itself intomedium Earth orbitusing aStar-27apogee motor.[2]
Mission
[edit]By 14 July 1978, OPS 5112 was in an orbit with aperigeeof 19,952 km (12,398 mi), anapogeeof 20,084 km (12,480 mi), aperiodof 711.30 minutes, and 63.10° ofinclinationto theequator.[6]The satellite had a design life of 5 years and a mass of 758 kg (1,671 lb).[2]It broadcast the PRN 07 signal in the GPS demonstration constellation, and was retired from service on 16 July 1981.
References
[edit]- ^abc"Display: Navstar 2 1978-047A".NASA. 14 May 2020.Retrieved20 November2020.
This article incorporates text from this source, which is in thepublic domain.
- ^abcdKrebs, Gunter."GPS (Navstar)".Gunter's Space Page.Retrieved12 July2012.
- ^abMcDowell, Jonathan."Launch Log".Jonathan's Space Report.Retrieved12 July2012.
- ^"Trajectory: Navstar 2 1978-047A".NASA. 14 May 2020.Retrieved20 November2020.This article incorporates text from this source, which is in thepublic domain.
- ^McDowell, Jonathan."Launch List".Launch Vehicle Database.Jonathan's Space Report. Archived fromthe originalon 15 August 2020.Retrieved12 July2012.
- ^McDowell, Jonathan."Satellite Catalog".Jonathan's Space Report.Retrieved12 July2012.
