Arabsat-1B
{{Short description|Saudi Arabian communications satellite}}
{{Infobox spaceflight
| name = Arabsat-1B
| image = STS-51-G Arabsat 1-B deployment.jpg
| image_caption = Deployment of Arabsat-1B from STS-51-G
| mission_type = Communication
| operator = Arabsat
| website =
| COSPAR_ID = 1985-048C
| SATCAT =
| mission_duration = 7 years
| spacecraft_bus = Spacebus 100
| manufacturer = Aérospatiale
| dry_mass =
| launch_mass = {{convert|1270|kg}}
| power =
| launch_date = {{start-date|17 June 1985, 11:33:00|timezone=yes}} UTC
| launch_rocket = {{OV|103}}
STS-51-G / PAM-D
| launch_site = Kennedy LC-39A
| launch_contractor = NASA
| entered_service =
| disposal_type =
| deactivated =
| orbit_epoch =
| orbit_reference = Geocentric
| orbit_regime = Geostationary
| orbit_periapsis =
| orbit_apoapsis =
| orbit_inclination =
| orbit_period = 24 hours
| orbit_longitude = 26° East
| orbit_slot =
| apsis = gee
| trans_band = 2 E/F-band
25 G/H-Band
| trans_frequency =
| trans_bandwidth =
| trans_capacity =
| trans_coverage =
| trans_TWTA =
| trans_EIRP =
| trans_HPBW =
}}
Arabsat-1B was a Saudi Arabian communications satellite which was operated by Arabsat. It was used to provide communication services to the Arab States. It was constructed by Aérospatiale, based on the Spacebus 100 satellite bus, and carried two NATO E/F-band (IEEE S band) and twenty five NATO G/H-Band (IEEE C band) transponders. At launch, it had a mass of {{convert|1270|kg}}, and an expected operational lifespan of seven years.{{cite web|url=http://space.skyrocket.de/doc_sdat/arabsat-1a.htm|title=Arabsat 1A, 1B, 1C / Insat 2DT|last=Krebs|first=Gunter|publisher=Gunter's Space Page|accessdate=2009-07-05}}
History
Arabsat-1B was launched aboard {{OV|103}} on mission STS-51-G. Discovery was launched from LC-39A at the Kennedy Space Center at 11:33:00 GMT on 17 June 1985.{{cite web|url=http://planet4589.org/space/log/launchlog.txt|title=Launch Log|last=McDowell|first=Jonathan|publisher=Jonathan's Space Page|accessdate=2009-07-05}} It was deployed from Discovery, and boosted to a geosynchronous transfer orbit by means of a PAM-D upper stage. Sultan bin Salman bin Abdulaziz Al Saud flew aboard the Shuttle to supervise deployment, becoming the first Saudi citizen and first member of royalty to fly in space. Morelos 1 and Telstar 303 were also deployed on the same mission.
Arabsat 1B was placed into a geosynchronous orbit at a longitude of 26° East.{{cite web|url=http://www.astronautix.com/project/arabsat.htm |title=Arabsat |last=Wade |first=Mark |publisher=Encyclopedia Astronautica |accessdate=2009-07-05 |url-status=dead |archiveurl=https://web.archive.org/web/20090331213805/http://www.astronautix.com/project/arabsat.htm |archivedate=2009-03-31 }} In October 1991, a problem developed with the spacecraft's attitude control system, causing it to drift eastward out of control.{{cite web|url=http://www.tbs-satellite.com/tse/online/sat_arabsat_1b.html|title=Arabsat 1B|publisher=TSE|accessdate=2009-07-05}} The same fault had developed aboard its sister satellite, Arabsat-1A, a month earlier.{{cite web|url=http://www.tbs-satellite.com/tse/online/sat_arabsat_1a.html|title=Arabsat 1A|publisher=TSE|accessdate=2009-07-05|archiveurl=https://web.archive.org/web/20090602183923/http://tbs-satellite.com/tse/online/sat_arabsat_1a.html|archivedate=2 June 2009|url-status=dead}} It failed completely in early 1992.
See also
{{Portal|Spaceflight}}