| Names | Navstar 8 GPS I-8 GPS SVN-8 |
|---|---|
| Mission type | Navigation Technology |
| Operator | U.S. Air Force |
| COSPAR ID | 1983-072A[1] |
| SATCATno. | 14189 |
| Mission duration | 5 years (planned) 9.75 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 | 14 July 1983, 10:21:00UTC |
| Rocket | Atlas E /SGS-2 (Atlas-75E) |
| Launch site | Vandenberg,SLC-3W[3] |
| Entered service | 10 August 1983 |
| End of mission | |
| Deactivated | 4 May 1993 |
| Orbital parameters | |
| Reference system | Geocentric orbit[4] |
| Regime | Medium Earth orbit (Semi-synchronous) |
| Perigee altitude | 19,917 km (12,376 mi) |
| Apogee altitude | 20,446 km (12,705 mi) |
| Inclination | 62.80° |
| Period | 718.00 minutes |
OPS 9794, also known asNavstar 8,GPS I-8 andGPS SVN-8, was an Americannavigation satellite launched in 1983 as part of theGlobal Positioning System development program. It was the eighth of elevenBlock I GPS satellites to be launched.[2]
Global Positioning System (GPS) was developed by theU.S. Department of Defense to 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]
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 watts. They hadS-band communications for control andtelemetry andUltra high frequency (UHF) cross-link between spacecraft. They were manufactured byRockwell Space Systems, were 5.3 meters across withsolar 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]
OPS 9794 was launched at 10:21 UTC on 14 July 1983, atop anAtlas Elaunch vehicle with anSGS-2upper stage. The Atlas used had the serial number 75E, and was originally built as an Atlas E.[3] The launch took place fromSpace Launch Complex 3W atVandenberg Air Force Base,[5] and placed OPS 9794 into a transfer orbit. The satellite raised itself intomedium Earth orbit using aStar-27apogee motor.[2]
By 10 August 1983, OPS 9794 had been raised to an orbit with aperigee of 19,917 km (12,376 mi), anapogee of 20,446 km (12,705 mi), aperiod of 718.00 minutes, and 62.80° ofinclination to 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 11 signal in the GPS demonstration constellation, and was retired from service on 4 May 1993.
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