USA-91

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USA-91
NamesNavstar 2A-11
GPS IIA-11
GPS II-20
GPS SVN-37
Mission type Navigation
Operator U.S. Air Force
COSPAR ID 1993-032A [1]
SATCAT no. 22657
Mission duration7.5 years (planned)
14.5 years (achieved)
Spacecraft properties
Spacecraft GPS IIA
Spacecraft type GPS Block IIA [2]
Manufacturer Rockwell International
Launch mass840 kg (1,850 lb)
Dimensions5.3 m (17 ft) of long
Power710 watts
Start of mission
Launch date13 May 1993, 00:07:00 UTC
Rocket Delta II 7925-9.5
(Delta D220)
Launch site Cape Canaveral, LC-17A
Contractor McDonnell Douglas
Entered service14 June 1993
End of mission
Disposal Graveyard orbit
Deactivated18 March 2016
Last contact20 December 2007
Orbital parameters
Reference system Geocentric orbit [3]
Regime Medium Earth orbit
(Semi-synchronous)
SlotC4 (slot 4 plane C)
Perigee altitude 20,033 km (12,448 mi)
Apogee altitude 20,334 km (12,635 mi)
Inclination 54.9°
Period 717.88 minutes
←  USA-90 (GPS IIA-10)
USA-92 (GPS IIA-12) →
 

USA-91, also known as GPS IIA-11, GPS II-20 and GPS SVN-37, was an American navigation satellite which formed part of the Global Positioning System. It was the eleventh of nineteen Block IIA GPS satellites to be launched.

Contents

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 introduction, GPS has also developed into a valuable tool for a wide range of civilian uses and sectors, including surveying, tracking corporate vehicle fleets, and outdoor enjoyment (such as sailing, flying, and hiking). 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-91 was launched at 00:07:00 UTC on 13 May 1993, atop a Delta II launch vehicle, flight number D220, flying in the 7925–9.5 configuration. [4] The launch took place from Launch Complex 17A (LC-17A) at the Cape Canaveral Air Force Station (CCAFS), [5] and placed USA-91 into a transfer orbit. The satellite raised itself into medium Earth orbit using a Star-37XFP apogee motor. [2]

Mission

On 14 June 1993, USA-91 was in an orbit with a perigee of 20,033 km (12,448 mi), an apogee of 20,334 km (12,635 mi), a period of 717.88 minutes, and 54.9° of inclination to the equator. [3] It broadcast signal PRN 07, and operated in slot 4 of plane C of the GPS constellation. [6] The satellite had a mass of 840 kg (1,850 lb). It had a design life of 7.5 years, [2] and ceased operations on 20 December 2007.

Following decommissioning, it was kept as a reserve satellite. It was finally put in a disposal orbit approximately 1000 km above the operational constellation on 18 March 2016. [7]

Related Research Articles

USA-87, also known as GPS IIA-8, GPS II-17 and GPS SVN-29, was an American navigation satellite which formed part of the Global Positioning System. It was the eighth of nineteen Block IIA GPS satellites to be launched.

USA-54, also known as GPS II-7 and GPS SVN-20, was an American navigation satellite which formed part of the Global Positioning System. It was the seventh of nine Block II GPS satellites to be launched, which were the first operational GPS satellites to fly.

USA-63, also known as GPS II-8 and GPS SVN-21, was an American navigation satellite which formed part of the Global Positioning System. It was the eighth of nine Block II GPS satellites to be launched, which were the first operational GPS satellites to fly.

USA-66, also known as GPS IIA-1, GPS II-10 and GPS SVN-23, was an American navigation satellite which formed part of the Global Positioning System. It was the first of nineteen Block IIA GPS satellites to be launched, and was the oldest GPS satellite still in operation until its decommissioning on 25 January 2016.

USA-71, also known as GPS IIA-2, GPS II-11 and GPS SVN-24, is an American navigation satellite which forms part of the Global Positioning System. It was the second of nineteen Block IIA GPS satellites to be launched.

USA-79, also known as GPS IIA-3, GPS II-12 and GPS SVN-25, was an American navigation satellite which formed part of the Global Positioning System. It was the third of nineteen Block IIA GPS satellites to be launched.

USA-80, also known as GPS IIA-4, GPS II-13 and GPS SVN-28, was an American navigation satellite which formed part of the Global Positioning System. It was the fourth of nineteen Block IIA GPS satellites to be launched.

USA-83, also known as GPS IIA-5, GPS II-14 and GPS SVN-26, is an American navigation satellite which forms part of the Global Positioning System. It was the fifth of nineteen Block IIA GPS satellites to be launched.

USA-84, also known as GPS IIA-6, GPS II-15 and GPS SVN-27, is an American navigation satellite which forms part of the Global Positioning System. It was the sixth of nineteen Block IIA GPS satellites to be launched.

USA-85, also known as GPS IIA-7, GPS II-16 and GPS SVN-32, was an American navigation satellite which formed part of the Global Positioning System. It was the seventh of nineteen Block IIA GPS satellites to be launched.

USA-88, also known as GPS IIA-9, GPS II-18 and GPS SVN-22, was an American navigation satellite which formed part of the Global Positioning System. It was the ninth of nineteen Block IIA GPS satellites to be launched.

USA-90, also known as GPS IIA-10, GPS II-19 and GPS SVN-31, was an American navigation satellite which formed part of the Global Positioning System. It was the tenth of nineteen Block IIA GPS satellites to be launched.

USA-92, also known as GPS IIA-12, GPS II-21, GPS SVN-39, and NAVSTAR 39, is an American navigation satellite which forms part of the Global Positioning System. It was the twelfth of nineteen Block IIA GPS satellites to be launched.

USA-94, also known as GPS IIA-13, GPS II-22 and GPS SVN-35, was an American navigation satellite which formed part of the Global Positioning System. It was the thirteenth of nineteen Block IIA GPS satellites to be launched.

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-100, also known as GPS IIA-15, GPS II-24 and GPS SVN-36, is an American navigation satellite which forms part of the Global Positioning System. It was the fifteenth of nineteen Block IIA GPS satellites to be launched.

USA-117, also known as GPS IIA-16, GPS II-25 and GPS SVN-33, is an American navigation satellite which forms part of the Global Positioning System. It was the sixteenth of nineteen Block IIA GPS satellites to be launched.

USA-126, also known as GPS IIA-17, GPS II-26 and GPS SVN-40, is an American navigation satellite which forms part of the Global Positioning System. It was the seventeenth of nineteen Block IIA GPS satellites to be launched.

USA-128, also known as GPS IIA-18, GPS II-27 and GPS SVN-30, is an American navigation satellite which forms part of the Global Positioning System. It was the eighteenth of nineteen Block IIA GPS satellites to be launched.

USA-135, also known as GPS IIA-19, GPS II-28 and GPS SVN-38, is an American navigation satellite which forms part of the Global Positioning System. It was the last of nineteen Block IIA GPS satellites to be launched.

References

  1. 1 2 3 "Display: Navstar 2A-11 1993-032A". NASA. 14 May 2020. Retrieved 19 December 2020.PD-icon.svg This article incorporates text from this source, which is in the public domain .
  2. 1 2 3 Krebs, Gunter. "GPS-2A (Navstar-2A)". Gunter's Space Page. Retrieved 10 July 2012.
  3. 1 2 "Trajectory: Navstar 2A-11 1993-032A". NASA. 14 May 2020. Retrieved 19 December 2020.PD-icon.svg This article incorporates text from this source, which is in the public domain .
  4. ↑ McDowell, Jonathan. "Launch Log". Jonathan's Space Report. Retrieved 10 July 2012.
  5. ↑ McDowell, Jonathan. "Launch List". Launch Vehicle Database. Jonathan's Space Report. Retrieved 10 July 2012.
  6. ↑ Wade, Mark. "Navstar". Encyclopedia Astronautica. Archived from the original on 11 November 2002. Retrieved 10 July 2012.
  7. ↑ "50 SW to dispose of two GPS satellites". United States Air Force. Retrieved 21 March 2016.PD-icon.svg This article incorporates text from this source, which is in the public domain .
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