The CHIPS Mission

The CHIPS spectrograph will be fabricated at the Space Sciences Laboratory of the University of California, Berkeley, and carried aboard a dedicated mini-satellite, called CHIPSat, to be provided by SpaceDev, Inc. The planned launch vehicle is a Boeing Delta II; its primary payload will be ICESAT to be launched into a 94° inclination, 600 km circular orbit.

The CHIPS mission will last one year. In its first six months, CHIPS will map the entire sky to a depth of about 40,000 seconds per resolution element (resel). Each resel is 5° × 26.7°; approximately 316 resels are required to cover the entire sky. This map should provide high S/N detections of the strongest emission lines. We can then spend the second six months making deep observations of regions of particular interest or mapping the emission in selected regions at higher spatial resolution (orienting the 5° × 26.7° field of view perpendicular to the initial survey direction). Alternatively, it may be more desirable to repeat the sky-mapping procedure, doubling the integration time in each resel.

CHIPSat is a three-axis stabilized spacecraft, with a solar-panel array roughly orthogonal to the field of view of the spectrograph. Based on our current estimates for the power budget, we plan for the solar panels to remain nearly fully illuminated on the sunlit side of the orbit, limiting the field of view to (approximately) a great circle perpendicular to the earth-sun line. During orbital night, the field of vew is unconstrained. We plan two inertial pointings per orbit, with brief changeovers near orbital noon and midnight. The overall observing efficiency should be high, as each slew requires only about a minute, and no more than ~20% of the time will be spent in the South Atlantic Anomaly, where high background rates may compromise the data.