Beyond lunar ice cube: next generation 12U orbiting lunar water explorer

We present a concept for a robust 12U version of an orbiting cubesat explorer for lunar water as a follow on to the Lunar Ice Cube mission with an upgraded IR spectrometer, CLEW, described in earlier work (ref). CLEW has significantly enhanced spectral range and spatial resolution with a modest (25%) increase volume, mass, and power, despite a requirement for cooling to 70K that can be accomplished with the high heritage Ricor 508 cooler. Made possible by the larger volume, two, rather than one, star tracker, and three larger momentum wheels will greatly improve knowledge and control of pointing, and that, combined with the detector readout design, will create the capability for resolving features of 1 km or smaller at 100 km altitude within the 10 x 10 field of view. The detector readout design also allows us to operate within the 256 kbps bandwidth limitation if it remains in the future. The power system, including 100 W generating solar panels and double the backup battery capacity, will be more than adequate for the payload needs. One option for the propulsion system we will need for the larger spacecraft is to replace the 3U volume ion propulsion drive system used on Lunar Ice Cube with a higher specific impulse chemical propulsion system, such as the hydrazine system used by Capstone, the successful 12U lunar orbiter communication, navigation and tracking pathfinder. That would significantly reduce the duration of cruise and ability for station-keeping to stay in a desirable science orbit for a much longer period of time.