  The astronomical community continues to be interested in suitable
programmable slit masks for use in multi-object spectrometers (MOSs) on space
missions. There have been ground-based MOS utilizing digital micromirror
devices (DMDs) and they have proven to be highly accurate and reliable
instruments. This paper summarizes the results of a continuing study to
investigate the performance of DMDs under conditions associated with space
deployment. This includes the response of DMDs to radiation, to the vibration
and mechanical shock loads associated with launch, and the operability of DMD
under cryogenic temperatures. The optical contrast ratio and a study of the
long-term reflectance of a bare device have also been investigated. The results
of the radiation testing demonstrate that DMDs in orbit would experience
negligible heavy-ion induced single event upset (SEU) rate burden, we predict
SEU rate of 5.6 micromirrors per 24 hours. Vibration and mechanical shock
testing was performed according to the NASA General Environmental Verification
Standard (GEVS), no mirrors failed in the devices tested. The results of low
temperature testing suggest that DMDs are not affected by the thermal load and
operate smoothly at temperatures at least as low as 78 K. The reflectivity of a
bare DMD did not measurably change even after being exposed to ambient
conditions over a period of 13 months. The measured contrast ratio (on state vs
off state of the DMD micromirrors) was greater than 6000/:1 when illuminated
with an f/4 optical beam. Overall, DMDs are extremely robust and promise to
provide a reliable alternative to micro shutter arrays (MSA) to be used in
space as remotely programmable slit masks for MOS design.
