TDRS-4

TDRS-4, known before launch as TDRS-D, is an American communications satellite, of first generation, which was operated by NASA as part of the Tracking and Data Relay Satellite System from 1989 until 2011. It was constructed by TRW, based on a custom satellite bus which was used for all seven of the first generation TDRS satellites.[3]

TDRS-4
TDRS-D being deployed from Discovery
Mission typeCommunication
OperatorNASA
COSPAR ID1989-021B
SATCAT no.19883
Website[]
Mission duration10 years (planned)
22 years (achieved)
Spacecraft properties
BusTDRS
ManufacturerTRW
Launch mass2108 kg [1]
Dimensions17.3 metres long
14.2 metres wide
Power1700 watts
Start of mission
Launch date13 March 1989, 14:57:00 UTC
RocketSpace Shuttle Discovery
STS-29R / IUS
Launch siteKennedy Space Center, LC-39B
ContractorRockwell International
End of mission
DisposalApril 2012
DeactivatedDecember 2011
Orbital parameters
Reference systemGeocentric orbit
RegimeGeostationary orbit
Longitude41.0° West (1988–2005)
46.0° West (2005–2011)
Epoch14 March 1989 [2]
 

History
The launch of STS-29 carrying TDRS-D.

TDRS-D was launched aboard Space Shuttle Discovery during the STS-29 mission in 1989. Discovery launched from Launch Complex 39B at the Kennedy Space Center at 14:57:00 UTC on 13 March 1989.[4] TDRS-D was deployed from Discovery a few hours after launch, and was raised to geostationary orbit by means of an Inertial Upper Stage.[4]

Deployment

The twin-stage solid-propellant Inertial Upper Stage made two burns. The first stage burn occurred shortly after deployment from Discovery, and placed the satellite into a geostationary transfer orbit (GTO). At 03:30 UTC on 14 March 1989, it reached apogee, and the second stage fired, placing TDRS-D into geostationary orbit.[5] At this point, it received its operational designation, TDRS-4. It was placed at a longitude 41.0° West of the Greenwich Meridian,[6][7] from where it provided communications services to spacecraft in Earth orbit, including the Space Shuttle and International Space Station. In 2005, it was relocated to 46.0° West.[6]

Retirement

TDRS-4 completed its planned mission in December 2011, and was subsequently removed to a disposal orbit 350 kilometres (220 mi) above GEO orbit belt, per International Telecommunications Union (ITU) and United Nations (UN) recommendations.[8] In May 2012, NASA reported that the orbit-raising manoeuvre had been completed successfully, and the spacecraft had been retired.[9]

Location of TDRS as of 26 May 2020
Location of TDRS as of 18 March 2019

References
  1. "UCS Satellite Database". Union of Concerned Scientists. 1 July 2009. Retrieved 9 August 2009.
  2. "NASA – NSSDCA – Spacecraft – Trajectory Details". nssdc.gsfc.nasa.gov. Retrieved 2 May 2018. This article incorporates text from this source, which is in the public domain.
  3. Krebs, Gunter. "TDRS 1, 2, 3, 4, 5, 6". Gunter's Space Page. Retrieved 9 August 2009.
  4. McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 9 August 2009.
  5. McDowell, Jonathan. "Index". Geostationary Orbit Catalog. Jonathan's Space Page. Retrieved 9 August 2009.
  6. "TDRS 4". TSE. Retrieved 9 August 2009.
  7. "The TDRS-J satellite". Spaceflight Now. 1 December 2002. Retrieved 9 August 2009.
  8. Johnson, Nicholas (5 December 2011). "Space debris issues". audio file, @1:03:05-1:05:10. The Space Show. Archived from the original on 27 January 2012. Retrieved 8 December 2011.
  9. "TDRS-4 Mission Complete; Spacecraft Retired From Active Service". NASA. 8 May 2012. Retrieved 11 May 2012. This article incorporates text from this source, which is in the public domain.
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