Galaxy 11

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Galaxy 11
Mission type Communication
Operator PanAmSat
Intelsat
COSPAR ID 1999-071A
Mission duration 15 years (planned)
Spacecraft properties
Bus HS-702
Manufacturer Hughes S&C
Launch mass 4,477 kilograms (9,870 lb)
Start of mission
Launch date 22 December 1999, 00:50 (1999-12-22UTC00:50Z) UTC
Rocket Ariane 44L
Launch site Kourou ELA-2
Contractor Arianespace
Orbital parameters
Reference system Geocentric
Regime Geostationary
Longitude 78.5° West(1999-2000)
99° West (2000)
91° West (2000-2008)
93° West (2008)
32.8° East (2008—)
Perigee 35,782 kilometres (22,234 mi)
Apogee 35,789 kilometres (22,238 mi)
Inclination 0 degrees
Period 24 hours
Transponders
Band 24 G/H band
40 J band

Galaxy 11 is an American geostationary communications satellite which is operated by Intelsat. It is located in geostationary orbit at a longitude of 32.8 degrees east, where it serves as a backup to the Intelsat 802 spacecraft. It was originally operated at 99° West and later spent most of its operational life at 91° West, from where it was used to provide communications services to Brazil and North America.[1]

Galaxy 11 was built for PanAmSat by Hughes Space and Communications, and is based around the HS-702 satellite bus. It was the first HS-702 to be launched, and the first satellite to be equipped with an XIPS propulsion system. It carries 24 G/H band and 40 J band (IEEE C and Ku bands respectively) transponders, and at launch it had a mass of 4,477 kilograms (9,870 lb), with an expected operational lifespan of around 15 years.[2][3]

As the first HS-702 to fly, Galaxy 11 was one of the six which were launched before a design flaw in the type's solar arrays was discovered. Solar concentrators, used to increase the amount of sunlight falling on the arrays, were fogging up due to vapours emitted by the satellite. This reduces the output of the solar arrays, and is expected to result in a reduced operational lifespan.[4] Following the discovery of the fault, US$130 million insurance was claimed on the satellite.[1] The satellite was transferred to Intelsat when it merged with PanAmSat in 2006.

The launch of Galaxy 11 was conducted by Arianespace, using an Ariane 44L carrier rocket flying from ELA-2 at the Guiana Space Centre. The launch occurred at 00:50 GMT on 22 December 1999.[5] It successfully placed Galaxy 11 into a geosynchronous transfer orbit, from which it raised itself to geostationary orbit by means of an onboard R-4D apogee motor. Its insertion into geosynchronous orbit occurred at 16:30 on 2 January 2000.[6] The satellite was originally scheduled to be launched by Sea Launch, on the maiden flight of the Zenit-3SL, however the contract was transferred to Arianespace, and Sea Launch replaced Galaxy 11 with a DemoSat for their maiden flight.[4]

It currently operates at 55.5° West.

See also[edit]

References[edit]

  1. ^ a b "Galaxy 11". TSE. Retrieved 2009-08-11. 
  2. ^ "UCS Satellite Database". Union of Concerned Scientists. 2009-07-01. Retrieved 2009-08-10. 
  3. ^ Krebs, Gunter. "Galaxy 11". Gunter's Space Page. Retrieved 2009-08-10. 
  4. ^ a b Harland, David M; Lorenz, Ralph D. (2005). Space Systems Failures (2006 ed.). Chichester: Springer-Praxis. ISBN 0-387-21519-0. 
  5. ^ McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 2009-08-10. 
  6. ^ McDowell, Jonathan. "Index". Geostationary Orbit Catalog. Jonathan's Space Page. Retrieved 2009-08-10.