Skynet 5B is a military

communications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. C ...

operated by

Astrium Services Astrium was an aerospace manufacturer subsidiary of the European Aeronautic Defence and Space Company (EADS) that provided civil and military space systems and services from 2006 to 2013. In 2012, Astrium had a turnover of €5.8 billion and 18 ...

, formerly

Paradigm Secure Communications Astrium was an aerospace manufacturer subsidiary of the European Aeronautic Defence and Space Company (EADS) that provided civil and military space systems and services from 2006 to 2013. In 2012, Astrium had a turnover of €5.8 billion and 18 ...

, on behalf of the British

Ministry of Defence {{unsourced, date=February 2021 A ministry of defence or defense (see spelling differences), also known as a department of defence or defense, is an often-used name for the part of a government responsible for matters of defence, found in states ...

. It was the second of four

Skynet 5 Skynet is a family of military communications satellites, now operated by Airbus Defence and Space on behalf of the United Kingdom's Ministry of Defence (MoD). They provide strategic and tactical communication services to the branches of the ...

satellites to be launched.

Spacecraft

The Skynet 5B spacecraft is a Eurostar 3000S satellite, constructed by

Astrium Astrium was an aerospace manufacturer subsidiary of the European Aeronautic Defence and Space Company (EADS) that provided civil and military space systems and services from 2006 to 2013. In 2012, Astrium had a turnover of €5.8 billion and 18 ...

. At launch it had a mass of approximately , with a design life of 15 years. Its

solar array A photovoltaic system, also PV system or solar power system, is an electric power system designed to supply usable solar power by means of photovoltaics. It consists of an arrangement of several components, including solar panels to absorb and ...

s will generate a minimum of 6 kilowatts to power its UHF and

X-band The X band is the designation for a band of frequencies in the microwave radio region of the electromagnetic spectrum. In some cases, such as in communication engineering, the frequency range of the X band is rather indefinitely set at approxim ...

communications systems. The Skynet 5 constellation was originally intended to consist of two satellites, the other of which,

Skynet 5A Skynet 5A is the first in a series of new-generation Skynet military communications satellites, used by the British Ministry of Defence. It was launched aboard an Ariane 5 carrier rocket at 22:03 GMT on 11 March 2007. Launch Skynet 5A was one ...

, 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 Skynet 5C is the third of four Skynet 5 military communications satellites to be used by the British Ministry of Defence (MOD). Launch It was launched from French Guiana aboard an Ariane 5ECA carrier rocket at 22:05:02 GMT on 12 June 2008. T ...

, 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.

Launch

Skynet 5B was launched by an Ariane 5ECA carrier rocket flying from

ELA-3 ELA-3 (french: Ensemble de Lancement Ariane 3, lit=Ariane Launch Complex 3), is a launch pad and associated facilities at the Centre Spatial Guyanais in French Guiana. ELA-3 is operated by Arianespace as part of the expendable launch system f ...

Kourou Kourou () is a commune in French Guiana, an overseas region and department of France in South America. Kourou is famous for being the location of the Guiana Space Centre, the main spaceport of France and the European Space Agency (ESA). It i ...

. The launch occurred at 22:06 UTC on 14 November 2007.

Star One C1 Star One C1 is a Brazilian communications satellite. It was launched on 14 November 2007 by an Ariane 5ECA carrier rocket, as part of a dual-payload launch with Skynet 5B. It was built by Thales Alenia Space, based on the Spacebus-3000B3 satellit ...

was launched aboard the same carrier rocket; Skynet 5B was mounted atop a

Sylda 5 Sylda is a village and a former municipality in the Mansfeld-Südharz district, Saxony-Anhalt, Germany. Since 1 January 2010, it is part of the town Arnstein Arnstein () is a town in the Main-Spessart district in the ''Regierungsbezirk'' of ...

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

geosynchronous transfer orbit A geosynchronous transfer orbit or geostationary transfer orbit (GTO) is a type of geocentric orbit. Satellites that are destined for geosynchronous (GSO) or geostationary orbit (GEO) are (almost) always put into a GTO as an intermediate step f ...

with 6 degrees of

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...

. The satellite used its apogee motor to raise itself into

geostationary orbit A geostationary orbit, also referred to as a geosynchronous equatorial orbit''Geostationary orbit'' and ''Geosynchronous (equatorial) orbit'' are used somewhat interchangeably in sources. (GEO), is a circular geosynchronous orbit in altitud ...

. It is located at a longitude of 53° East, in an orbit with a

perigee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any ellip ...

of , an

apogee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any ellip ...

of , and 0 degrees inclination.

References

{{Orbital launches in 2007 Spacecraft launched in 2007 Military satellites Satellites of the United Kingdom Satellites using the Eurostar bus Spacecraft launched by Ariane rockets