3 February 2012

Astrium installs millionth solar cell as it delivers its 300th array

Astrium — the space subsidiary of the European Aeronautic Defence and Space Company (EADS) — says that its centre of competence for solar arrays in Ottobrunn, Germany, which has been equipping spacecraft with power plants for nearly 50 years, has installed the 1 millionth solar cell from its supplier AZUR Space Solar Power GmbH of Heilbronn, Germany, and delivered its 300th solar array in the presence of Dr Martin Zeil, the Bavarian State Minister of Economic Affairs, Infrastructure, Transport and Technology. Astrium has also signed a long-term cooperation agreement with AZUR Space.

The 100-strong Astrium team is currently preparing the solar arrays for the European Space Agency’s BepiColombo interplanetary probe to Mercury. The firm is also developing what is claimed to be the world’s most modern solar array for the new European ALPHABUS telecoms satellite.

“Weather observation, environmental monitoring, disaster management, navigation, telecommunications from space and numerous scientific missions – all these applications would be impossible without Astrium’s particularly reliable solar arrays,” says Evert Dudok, CEO of Astrium Satellites. “Today’s modern gallium arsenide solar cells, that we install in space, have now reached an efficiency of up to 28%, making them more than twice as efficient as the solar cells currently used for roof installations,” he adds. “As the number one European company for space technologies, we are acting as an innovation driver for terrestrial applications.”

The environmental conditions in space are very harsh, with extreme temperatures ranging from –180ºC to +130ºC coupled with solar radiation, so solar cells on spacecraft need to be extremely robust. The solar arrays developed and made by Astrium have an output ranging from a few hundred watts up to 26kW. Featuring about 20,000 solar cells and a wingspan of up to 19m (for each panel either side of the spacecraft), a solar array weighs no more than 145kg and is folded during launch to a thickness of 30cm. Once the satellite is in space, two of these solar wings are deployed either side of the satellite. To date, no Astrium solar arrays have failed while in operation.

The Astrium solar panel production facility in Ottobrunn features three parallel integration lines, enabling up to nine large arrays to be in production simultaneously. A 4200m2 cleanroom provides space for production, integration and testing, benefiting from all development and manufacturing processes being carried out in a single place.

To be able to withstand the challenging conditions they will experience in space, the solar panels are coated with a protective layer made from glass, bonded to a carbon-fiber substrate and then wired. The electrical configuration must be designed to ensure that the satellite receives the necessary power at all times. Astrium guarantees that the arrays will still be able to deliver the final service agreed with the customer after 15 years in service.

Astrium has also developed a patented method of detecting potential breakages and other defects in its solar cells, further increasing the arrays’ quality. Though normally programmed to receive light and emit power, solar cells can also be operated in reverse – i.e. consuming power and emitting light as electroluminescence. A special camera can then be used to examine the illuminated solar cells to detect breakages and other defects.

The European Space Agency’s BepiColombo probe is due to depart to Mercury in 2014. The biggest challenge is preparing the arrays to withstand temperature fluctuations ranging between –130ºC and +270ºC and to protect them from the sun’s intense UV radiation. To date, there is no direct experience from comparable projects having to endure these extreme conditions.

Tags: Azur Space Multi-junction CPV

Visit: www.astrium.eads.net

Visit: www.azurspace.com