MOEMS devices designed and tested for astronomical instrumentation in space

Next-generation astronomical instrumentation for ground-based and space telescopes could use MOEMS devices. Among them, Multi-Object Spectrographs (MOS) are the major instruments for studying primary galaxies and remote and faint objects. A promising solution for the object selection system is the use of MOEMS devices such as micromirror arrays (MMA) which allow the remote control of the multi-slit configuration in real time. We are engaged in a European development of MMA for generating reflective slit masks. Prototypes of MMA with 2048 individually addressable micromirrors made of single-crystal silicon were successfully designed, fabricated and tested. 100×200μm2 micromirrors can be tilted by electrostatic actuation yielding 24° mechanical tilt-angle. The micromirrors were successfully actuated before, during and after cryogenic cooling at 162K. Line-column addressing for individual mirrors has also been demonstrated. We were also engaged in a technical assessment of using a 2048 × 1080 DMD from Texas Instruments for space applications. For a MOS in space, the device should work in vacuum and at low temperature. Our tests reveal that the DMD remains fully operational at -40°C and in vacuum. A 1038 hours life test in space survey conditions, Total Ionizing Dose radiation, thermal cycling and vibrations/shocks have also been successfully completed. These results do not reveal any show-stopper concerning the ability of the DMD to meet environmental space requirements. These developments and tests demonstrate the full ability of this type of components for space instrumentation, especially in multi-object spectroscopy applications.