NEOSSat is the technological offspring of the MOST astero-seismology microsatellite, which began its mission in 2003 (launched June 30th and still operating as of this writing).
NEOSSat is a suitcase-sized microsatellite (~0.9 x 0.65 x 0.35 m body with a telescope baffle protruding ~0.5 m; mass ~74 kg) powered by multi-band gap solar panels and stabilised/slewed by a system of miniature reaction wheels. Excess momentum is dumped by magnetorquers pushing against Earth’s magnetic field.
One of the impressive features of the design is the high precision attitude control achieved by MOST, which will be improved upon with NEOSSat; the high precision stability is required because the telescope is most often used by the NESS project as a framing camera – the telescope must point at precisely the same patch of sky for intervals up to 100 seconds long.
Like MOST, NEOSSat is carrying an optical telescope with a 15-centimetre mirror. With no moving parts, this telescope’s optics are focused in the assembly building and built to survive the launch vibrations. Light enters the telescope and reflects off of a secondary mirror as shown in this diagram, before being sent to two CCDs (Charge Coupled Devices). One is the imaging CCD used by the NESS and HEOSS projects; the other is the star tracker CCS which is used by the attitude control system to stabilize or slew the spacecraft.
With the planned exposure times and survey regions of the NESS project, the instrument was designed to achieve limiting V magnitudes will range from ~19.5 to ~20 with 100-second exposures. (The human eye only sees down to 6th magnitude.)