Released 24/05/2017. Copyright ESA, CC BY-SA 3.0 IGO
A strong but lightweight mirror for space, made from silicon carbide ceramic, is being subjected to the temperature levels and vacuum encountered in orbit.
The 95 cm-diameter mirror consists of three separate petals fused together ahead of grinding and polishing.
The aim of the test, led for ESA by AMOS in Belgium, was to check if the combination of joints would induce optical distortion when the mirror’s temperature was brought close to –150°C.
A compound of silicon and carbon, SiC was first synthesised in 1893 in an attempt to make artificial diamonds. The result was not so far off: today, SiC is one of the hardest-known materials, used to make cutting tools, high-performance brakes and even bulletproof vests. Crystalline in nature, it is also used for jewellery.
Small amounts of SiC have been unearthed inside meteorites – it is relatively common in deep space. Its strong, lightweight nature made it a natural for human-made space projects too.
ESA produced the largest SiC mirror ever to fly in space for the Herschel telescope, launched in 2009. At 3.5 m in diameter, this reflector had twice the observing area of the Hubble Space Telescope while having one third of its mass.
Once mastered by ESA, SiC technology has since been used to manufacture a wide variety of space mirrors and optical supports, for missions such as Gaia, Sentinel-2 and the James Webb Space Telescope.
Performed through ESA’s General Support Technology Programme, which develops promising technologies for space, the results of the test proved to be perfectly acceptable for optical telescopes. To find out more about ESA research and development projects, check our new Shaping the Future website.
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The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.
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