Alphasat reaches temporary geostationary orbit

Inmarsat (LSE:ISAT.L), the leading provider of global mobile satellite communications services, has announced that Alphasat, one of the most technically advanced telecommunications satellites ever constructed for civilian applications, has successfully reached its temporary post in geostationary orbit. Alphasat was launched on an Ariane 5 ECA launcher from French Guiana on 25th July.

The satellite will remain in its current orbit for several weeks while Inmarsat, together with its Alphasat partner, the European Space Agency (ESA), continue in-orbit testing. This will include testing of all AlphaBus platform subsystems and the commissioning of its innovative digital processing L-band payload, in addition to the spacecraft's four Technology Demonstration (hosted) Payloads (TDP).

A Successful cooperation during Early Operations

During the past few days, the satellite has successfully achieved a number of significant milestones. These include the successful boost of the spacecraft into geostationary orbit and the deployment of the four-panel solar array.

In addition to deploying the massive arrays, which span almost 40 metres (131 feet), the spacecraft has also deployed its L-band reflector. In an operation lasting more than 24 hours, the reflector was released from the satellite and unfurled slowly to its final diameter of 11 metres.

All of these critical operations were successfully conducted by a team from Astrium and Thales Alenia Space, managed by Inmarsat and supported by ESA and CNES, in a cooperative effort unprecedented in the European space industry.

“We are extremely pleased with the performance of Alphasat so far. It has performed flawlessly and we have retired a significant amount of the mission risk after the successful mechanical deployments and earth pointing acquisition. Once we finish testing the payload, Alphasat will be ready for operations. It has been a well-executed, collaborative team effort by all involved,” said Ruy Pinto, Inmarsat Chief Technology Officer.

Technology Demonstration Payloads (TDP)

The first TDP to be operated in orbit is the TDP 6 Star Tracker from Jeno-Optronik GmBh, one of the leading instruments and subsystem suppliers in the international space market, which was switched on soon after launch. The demonstration payload is operating nominally in star tracking mode and the first data from the Star Tracker has been downloaded and is currently being evaluated.

Global broadband

Alphasat joins Inmarsat's award-winning I-4 satellite fleet, which has been powering global broadband connectivity for government and commercial customers in the L-band since 2009. The new satellite will provide additional mobile satellite communications capacity over Europe, the Middle East and Africa.

Key Features of AlphaBus

The Alphabus product line is Europe's response to market demand for increased broadcasting services. It can accommodate missions with up to 22kW of payload power and a payload mass up to two tonnes. As a high-power multi-purpose platform, Alphabus gives European industry an unprecedented and unique position in the global telecom market.

Further information

About Inmarsat

Inmarsat plc is the leading provider of global mobile satellite communications services. Since 1979, Inmarsat has been providing reliable voice and high-speed data communications to governments, enterprises and other organizations, with a range of services that can be used on land, at sea or in the air. Inmarsat employs around 1,600 staff in more than 60 locations around the world, with a presence in the major ports and centres of commerce on every continent. Inmarsat is listed on the London Stock Exchange (LSE:ISAT.L). For more information, please visit

Jonathan Sinnatt
Head of Corporate Communications
T: +44 (0)20 7728 1935
E: [email protected]