Skynet 5B
{{Infobox spaceflight
| name = Skynet 5B
| image = Skynet-5 satellite.jpg
| image_caption =
| mission_type = Military communications
| operator = Paradigm Secure Communications
EADS Astrium
On behalf of British Ministry of Defence
| website =
| COSPAR_ID = 2007-056B
| SATCAT =
| mission_duration = 15 years
| spacecraft_bus = Eurostar 3000S
| manufacturer = Astrium
| dry_mass =
| launch_mass = {{convert|4635|kg}}
| power =
| launch_date = {{start-date|14 November 2007, 22:06|timezone=yes}} UTC
| launch_rocket = Ariane 5ECA V179
| launch_contractor = Arianespace
| entered_service =
| disposal_type =
| deactivated =
| orbit_epoch =
| orbit_reference = Geocentric
| orbit_regime = Geostationary
| orbit_periapsis =
| orbit_apoapsis =
| orbit_inclination =
| orbit_period =
| 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.
Spacecraft
The Skynet 5B spacecraft is a Eurostar 3000S satellite, constructed by Astrium. At launch it had a mass of approximately {{convert|4635|kg}}, with a design life of 15 years.{{cite web|url=https://space.skyrocket.de/doc_sdat/skynet-5.htm|title=Skynet 5A, 5B, 5C, 5D|first=Gunter|last=Krebs|work=Gunter's Space Page|accessdate=28 January 2013}} Its {{convert|34|m|ft|adj=on}} solar arrays will generate a minimum of 6 kilowatts{{cite web|url=http://www.arianespace.com/images/launch-kits/launch-kit-pdf-eng/07_nov_9.pdf|title=A dual launch for Brazil and the British MoD|publisher=Arianespace|access-date=28 January 2013|date=9 November 2007|url-status=dead|archive-url=https://web.archive.org/web/20131029204749/http://www.arianespace.com/images/launch-kits/launch-kit-pdf-eng/07_nov_9.pdf|archive-date=29 October 2013}} 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.{{cite web|url=https://www.army.mod.uk/equipment/communication/1528.aspx|title=Skynet 5 Satellite Communications|publisher=British Army|access-date=28 January 2013|url-status=dead|archive-url=https://web.archive.org/web/20120920195908/http://www.army.mod.uk/equipment/communication/1528.aspx|archive-date=20 September 2012}}
Launch
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.{{cite web|url=http://news.bbc.co.uk/1/hi/sci/tech/7095344.stm|title=UK military spacecraft launched|first=Jonathan|last=Amos|publisher=BBC News|date=14 November 2007|accessdate=28 January 2013}}{{cite web|url=https://www.nasaspaceflight.com/2007/11/ariane-5-eca-launches-with-skynet-5b-and-star-one-c1/|title=Ariane 5 ECA launches with Skynet 5B and Star One C1|first=Chris|last=Bergin|publisher=NASASpaceflight.com|date=14 November 2007|accessdate=28 January 2013}} 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.
Orbit
The launch placed Skynet 5B into a {{convert|250|by|35786|km}} geosynchronous transfer orbit with 6 degrees of inclination.{{cite web|url=https://spaceflightnow.com/ariane/v179/|title=Ariane 5 launches British and Brazilian satellites|first=Stephen|last=Clark|publisher=Spaceflight Now|date=14 November 2007|accessdate=28 January 2013}} The satellite used its apogee motor to raise itself into geostationary orbit. It is located at a longitude of 53° East, in an orbit with a perigee of {{convert|35572|km}}, an apogee of {{convert|35867|km}}, and 0 degrees inclination.{{cite web|url=https://planet4589.org/space/log/satcat.txt|title=Satellite Catalog|first=Jonathan|last=McDowell|work=Jonathan's Space Page|accessdate=28 January 2013}}
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References
{{Portal|Spaceflight}}
{{Reflist}}
{{Skynet}}
{{Orbital launches in 2007}}
Category:Spacecraft launched in 2007
Category:Military satellites of the United Kingdom