Magic material: silicon carbide is helping us learn more about the universe
The largest mirrors in space
Airbus Defence and Space’s unique expertise in the field of silicon carbide is revolutionising space optics while expanding Europe’s technology base.
At 3.5 metres, Herschel is the largest imaging telescope ever launched( Photo by Airbus)
It started in the 1990s: astronomical telescopes were becoming larger and we needed a new material to reduce the mirror weight,” explains Airbus Defence and Space’s Emmanuel Sein.
The answer was silicon carbide: lighter than metal or glass, it can be optically polished making it perfect for high performance lightweight mirrors. It also has excellent structural stability and thermal properties: vital for the accuracy of a telescope when temperatures in space plummet to -240°C.
New frontiers with Herschel
Having recognised the potential, Airbus Defence and Space (Airbus DS) joined together with French ceramic material specialist Mersen to form Boostec. “Our partner had experience in manufacturing small silicon carbide parts, but we were looking at dimensions of three metres or more,” says Sein.
After successfully completing a high-precision silicon carbide camera for the Rosetta mission, Airbus DS then built the Herschel Space Observatory for the European Space Agency (ESA), launched in 2009.
“The primary mirror is the largest single space telescope mirror in the world, 3.5 metres in diameter and weighing approximately 300 kg ,” says Sein. “If it had been built with standard optical materials instead of advanced aerospace materials, the mass would have been three tonnes.”
Gaia: embedded telescope during integration (Photo by Airbus Group)
The shape of telescopes to come
Using this same expertise, Airbus DS has also built the Gaia spacecraft, launched in 2013 and made almost entirely from silicon carbide. It has the most sensitive telescope ever made and is currently gathering data for a 3D map of our galaxy.
Airbus DS is now working on part of the James Webb Space Telescope (JWST), which will launch in 2018. The company is building its NIRSpec ‘super eye’, a 200kg spectrograph made entirely from silicon carbide that will be able to detect the faintest radiation from the most distant galaxies.
Furthermore, Airbus DS is manufacturing the complete payload module of ESA’s Euclid mission, which incorporates a 1.2 metre-diameter telescope made from silicon carbide. This instrument will map and investigate the nature of dark energy and dark matter in the universe.
Source: Airbus Group – 31 March 2016
