Astrium’s ground-breaking developments in lightweight silicon-carbide technology were fundamental to the realisation of this programme; the company built the satellite’s all-silicon carbide (SiC) space telescope, which is collecting the light from distant and poorly known objects, such as newborn galaxies thousands of millions of light-years away.
SiC is an exceptional material whose mechanical-thermal properties allow the manufacture of ultra lightweight but very large instruments: the Astrium mirror, at 3.5m, is the largest imaging telescope ever launched, and yet the Herschel telescope weighs just 350kg, as opposed to the 1.5 tons which would be required with standard technology.
Under a second contract, Astrium was responsible for the fully integrated payload module that consisted of the:
- cryostat
- optical bench
- scientific instrument harness
- solar array & sun shade (supplied by Astrium subsidiary Dutch Space)
- telescope & SVM interface structure, and performance of the satellite assembly, integration & test (AIT) programme.
In order to prevent the instruments' own infrared radiation from drowning out the received signal, they are cooled inside a cryogenic unit – called a cryostat – down to –271° C (about two degrees above absolute zero). At this temperature the sensitive science instruments have the potential to penetrate the unknown areas of the cold, early universe.
The cryostat is the central unit of the payload module and was built under the leadership of Astrium. The low temperature is achieved using superfluid helium. For the construction of cryostat, Astrium was able to draw on the experience it gained from Herschel's precursor, the European Infrared Space Observatory (ISO) which was successfully operated from 1996 to 1998.
