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USA-96, also known as GPS IIA-14, GPS II-23 and GPS SVN-34, is an American navigation satellite which is part of the Global Positioning System. It was 14 of 19 Block IIA GPS satellites to be launched, and the last one to be retired.

USA-96

Names	Navstar 2A-14 GPS IIA-14 GPS II-23 GPS SVN-34
Mission type	Navigation
Operator	U.S. Air Force
COSPAR ID	1993-068A[1]
SATCAT no.	22877
Mission duration	7.5 years (planned) 26 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	26 October 1993, 17:04:00 UTC
Rocket	Delta II 7925-9.5 (Delta D223)
Launch site	Cape Canaveral, LC-17B
Contractor	McDonnell Douglas
Entered service	25 November 1993
End of mission
Disposal	Graveyard orbit
Deactivated	9 October 2019
Orbital parameters
Reference system	Geocentric orbit[3]
Regime	Medium Earth orbit (Semi-synchronous)
Slot	D4 (slot 4 plane D)
Perigee altitude	20,107 km (12,494 mi)
Apogee altitude	20,264 km (12,591 mi)
Inclination	55.08°
Period	718.00 minutes
Global Positioning System ← USA-94 (GPS IIA-13) USA-100 (GPS IIA-15) →

Background

Global Positioning System (GPS) was developed by the U.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 55.0°. 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 were 3-axis stabilized, nadir pointing using reaction wheels. Dual solar arrays supplied 710 watts of power. They used S-band (SGLS) communications for control and telemetry and Ultra high frequency (UHF) cross-link between spacecraft. The payload consisted of two L-band navigation signals at 1575.42 MHz (L1) and 1227.60 MHz (L2). Each spacecraft carried 2 rubidium and 2 Cesium clocks and nuclear detonation detection sensors. Built by Rockwell Space Systems for 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

USA-96 was launched at 17:04:00 UTC on 26 October 1993, atop a Delta II launch vehicle, flight number D223, flying in the 7925-9.5 configuration.[4] The launch took place from Launch Complex 17B (LC-17B) at the Cape Canaveral Air Force Station (CCAFS),[5] and placed USA-96 into a transfer orbit. The satellite raised itself into medium Earth orbit using a Star-37XFP apogee motor.[2]

Mission

On 25 November 1993, USA-96 was in an orbit with a perigee of 20,104 km (12,492 mi), an apogee of 20,260 km (12,590 mi), a period of 718.00 minutes, and 55.08° of inclination to the equator.[3] It broadcast the PRN 04 signal, and operated in slot 4 of plane D 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] It was temporarily removed from the GPS constellation on 2 November 2015.[7] From 20 March 2018 the satellite was operational again, broadcasting the PRN 18 signal, from slot 6 of Plane D,[8] until 9 October 2019, when it was placed in reserve as an on-orbit spare.[9] It was the final Block IIA satellite to be retired on 13 April 2020.[10]

References

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