| Skynet 5B | |
| Mission Type: | Military communications |
| Operator: | Paradigm Secure Communications EADS Astrium On behalf of British Ministry of Defence |
| Cospar Id: | 2007-056B |
| Mission Duration: | 15 years |
| Spacecraft Bus: | Eurostar 3000S |
| Manufacturer: | Astrium |
| Launch Date: | UTC |
| Launch Rocket: | Ariane 5ECA V179 |
| Launch Site: | Kourou ELA-3 |
| Launch Contractor: | Arianespace |
| Orbit Reference: | Geocentric |
| Orbit Regime: | Geostationary |
| Orbit Longitude: | 25° East |
| Apsis: | gee |
Skynet 5B is a military communications satellite operated by Astrium Services, formerly Paradigm Secure Communications, on behalf of the British Ministry of Defence. It was the second of four Skynet 5 satellites to be launched.
The Skynet 5B spacecraft is a Eurostar 3000S satellite, constructed by Astrium. At launch it had a mass of approximately, with a design life of 15 years.[1] Its 34m (112feet) solar arrays will generate a minimum of 6 kilowatts[2] to power its UHF and X-band communications systems.
The Skynet 5 constellation was originally intended to consist of two satellites, the other of which, Skynet 5A, was launched earlier in 2007. By the time of Skynet 5B's launch, a decision had been made to launch the backup spacecraft, Skynet 5C, as an on-orbit spare; this was launched in 2008. Skynet 5D was ordered to replace the backup, however this too was launched in 2012. Skynet 5 replaced the earlier Skynet 4 system.[3]
Skynet 5B was launched by an Ariane 5ECA carrier rocket flying from ELA-3 at Kourou. The launch occurred at 22:06 UTC on 14 November 2007.[4] [5] Star One C1 was launched aboard the same carrier rocket; Skynet 5B was mounted atop a Sylda 5 adaptor, with Star One C1 attached to the upper stage underneath the Sylda. Skynet 5B was the first of the two spacecraft to separate from the carrier rocket.[2]
The launch placed Skynet 5B into a 250by geosynchronous transfer orbit with 6 degrees of inclination.[2] [6] The satellite used its apogee motor to raise itself into geostationary orbit.[5] It is located at a longitude of 53° East, in an orbit with a perigee of, an apogee of, and 0 degrees inclination.[7]