European Space Agency

Alphasat's journey to meet its launcher

Alphasat, the most sophisticated commercial communications satellite ever built, left Astrium´s facilities in Toulouse on 17 June. After completion of its final integration and test campaign, it was transported by an Antonov 124 aircraft to Kourou, French Guiana, to be prepared for its launch aboard an Ariane 5, scheduled for 25 July.

Environmental conditions were checked during transport to make sure everything was safe and the intricate technology on board remained in good order. Once its journey was over, the container was left overnight in an airlock to decontaminate and allow for the environmental conditions to stabilise.

After a night decontaminating in the Kourou airlock, Alphasat’s parts were carefully inspected to make sure that nothing had sustained any damage during the trip from Toulouse to the launch site in French Guiana.

Alphasat is unpacked from its container

The inspection was followed by a procedure called “touch and go” where the parts of the satellite and rocket meant to join together are checked to ensure they match up.  For this, the team used a flight adapter provided by the Arianespace launcher company.

While the inspection of Alphasat and its on-board technology took place, all of the ground test equipment was also unpacked and calibrated. 

The "touch and go" test using the Arianespace flight adapter

Following the inspection of Alphasat, the electric propulsion system was filled with more than 200 kg of xenon.  This propulsion system will be used by the satellite to regulate its north-south station-keeping and so maintain its position once it reaches orbit.

Over the next two weeks the satellite’s thrusters will be filled with chemical propellant.  The chemical fuel of bi-propellant and helium will drive the satellite to geostationary orbit after launch.

Once testing and fuelling are complete, Alphasat will be taken to the Final Assembly Building to be joined to the Ariane 5 launcher in mid-July.  The process of combined operations to join the satellite to its launcher will then take place over the following week and a half.  The launch is scheduled for 25 July from Europe’s Spaceport in Kourou, French Guiana.

Background information about Alphasat

Alphasat has its solar arrays installed at Astrium

Designed and built by Astrium for Inmarsat and ESA, Alphasat embodies three outstanding achievements in one single programme:

  • Alphasat carries a new generation of advanced geomobile communications payload in L-band that will augment Inmarsat’s broadband network service across Europe, Africa and the Middle East, providing new capabilities in terms of performance and resource availability.

    It also delivers additional L-band space segment redundancy and consolidates safety of life services for the aeronautical and maritime sectors. The payload design and production was led by Astrium in the UK.

    This payload features eight new generation digital signal processors, which are able to efficiently manage multiple communications with maximum flexibility in both frequency and beam power allocation, and an 11 meter antenna reflector.

  • Alphasat also carries four ESA Technology Demonstration Payloads, including a laser communications terminal, developed under German space agency DLR contract. It is a precursor of the operational system for EDRS (European Data Relay System) enabling very high speed transmission between LEO and GEO which will greatly enhance Earth observation applications and services.
  • On top of that, Alphasat is the first flight model of the new high capacity European satellite platform Alphabus which has been jointly developed by Astrium and Thales Alenia Space with ESA and French space agency CNES support, to address the upper range of the communications satellite market.

    The Alphabus platform is the most powerful platform on the market, capable of conducting missions with a satellite launch mass of up to 8,800kg, a payload power of up to 22kW and a payload mass up to 2,000kg.

Alphasat has been designed for 15 years of in-orbit lifetime and will have a launch mass of 6,650 kg and a wingspan of 40 meter once its solar arrays are deployed in orbit. Launch and Early Orbit Phase operations will be conducted from the Astrium spacecraft control centre in Toulouse.

Event Date

03 July 2013
Published 03 July 2013
Last updated at 03 July 2013 - 10:21