Observing modes of the SPRITE 12U CubeSat: a probe of star formation feedback with far-UV imaging spectroscopy

SPRITE (Supernova Remnants and Proxies for Reionization Testbed Experiment) is a 12U CubeSat mission funded by NASA and led by the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado, Boulder. The payload will house the first sub-arcminute resolution Far-Ultraviolet (FUV) long-slit spectrograph with access to the Lyman UV (912 − 1216 Å), enabled by new enhanced lithium fluoride coatings and an ultra-low-noise photon-counting microchannel plate (MCP) detector. The scientific mission has two main components: constraining the escape fraction of ionizing Lyman-Continuum (LyC) radiation from low-redshift galaxies (0.14 ≤ z ≤ 0.4) and measuring feedback from nearby star forming regions and supernova remnants. Enabling the scientific mission are two distinct observing modes. For the faintest sources, we will operate the MCP detector in photon-counting mode. For brighter sources, we will operate the MCP in an accumulation / integration mode. For extended sources we will collate multiple pointings of the long slit, stepping across the field of view in a ‘push broom’ mapping to create 3D spectroscopic cubes. SPRITE will also take weekly calibration data to characterize the degradation of the coatings and detector. We present these observing modes along with the data acquisition and processing pipeline required to enable scientific analysis on the ground.