2002–2004 | CSEM's teams worked on a programmable slit mask, which was intended as a backup for the Webb telescope's highly sensitive multi-object spectrograph. To function properly, the spectrograph needs to be coupled to a mask with tiny slits, which act as shutters to filter the light being analyzed. This mask allows researchers to collect the light emitted by the object they are observing while blocking out rays emitted by other stars. It can then be used to measure parameters such as total mass, temperatures or the composition of matter in the universe.

The high-precision mechanism developed by the engineers is made up of bars, guided by wheels, which are capable of withstanding the extreme conditions to which space telescopes are subjected (vibrations, cryogenic temperatures, etc.). In the end, CSEM's concept was not selected, but it paved the way for numerous mechatronic projects for a new generation of ground-based telescopes.

To learn more:

• earth.esa.int/web/eoportal/satellite-missions/j/jwst
• www.jwst.nasa.gov/