What is Skynet? A look at Britain’s military communications satellites

Skynet is a family of commercially managed military communications satellites operated on behalf of the Ministry of Defence, which provide strategic communication services to the British Armed Forces and UK allies.

Skynet 5 is most recent generation of the family, replacing the existing Skynet 4 Stage 2 system. The satellites have been contracted via PFI to a partnership between Paradigm Secure Communications and EADS Astrium, parts of Airbus. EADS Astrium were responsible for the build and delivery of Skynet 5 satellites in orbit, whilst subsidiary company Paradigm will be responsible for provision of service to the MoD.

Paradigm have also been contracted to provide communications services to NATO using spare capacity on the satellites according to the Ministry of Defence who also say that the programme marks a change of approach in the UK from traditional defence procurement methods to a services-based contract which also includes provision of leased ground terminals, Reacher vehicles, the Satellite Communications Onboard Terminal for ships, and the associated baseband equipment.

According to Airbus:

“The Skynet 5 satellite is based on the Eurostar E3000 bus design, weighs about 4,700 kilograms (5.2 short tons), has two solar panels each about fifteen metres long, and has a power budget of five kilowatts. It has four steerable transmission dishes, and a phased-array receiver designed to allow jamming signals to be cancelled out. They will also resist attempts to disrupt them with high-powered lasers.”

Below are the technical specifications, again from Airbus:

The fleet of military X-band satellites have been specifically designed to support smaller, low powered, tactical terminals. Each Skynet 5 satellite is equipped with:

• High power 160W TWTAs on all transponders, giving 56 dBW peak EIRP in each transmit spot beam and 41 dBW peak EIRP in each global beam per transponder.
• 15 active transponders ranging in bandwidth from 20 MHz to 40 MHz
• Up to 9 UHF channels
• Multiple fully steerable downlink spot beams
• On Board Active Receive Antenna (OBARA) capable of generating multiple shaped uplink beams
• Flexible switching capability allowing connectivity between any uplink beam and at least two downlink beams
• Nuclear hardening, anti-jamming countermeasures and laser protection

Initially two Skynet 5 satellites were to be built, with insurance covering any launch loss; the MoD later decided to have a third satellite built in advance, and later still to have the third satellite launched to serve as an on-orbit spare.

Recently, satellite ‘Skynet 5A’ moved from its position over Europe, the Middle East and Africa, making Skynet services available over the eastern Asia-Pacific region, including in Australia which will also host a new ground station. An official said:

“The announcement that Airbus will be moving one of the UK’s Skynet satellites to the eastern Asia-Pacific region is clear proof of how much our relationships with our international allies matter. This is the first time that we have had a secure communications capability in the region, and shows the depth of our commitment to our allies and partners in the region, including Malaysia, in humanitarian and peacekeeping operations.”

The agreement of the British government to move the satellite is believed to be part of a broad programme of increased cooperation with Asian and Pacific allies.

Colin Paynter, head of Airbus Space and Defence, said:

“The Skynet 5 constellation consists of the world’s most powerful, nuclear hardened and protected, military X-band and UHF satellites. With the move of Skynet 5A, we will expand the availability of our premium secure MILSATCOM services to allied nations in the region who need high grade resilient and secure communications services to complement their existing systems.”