Since the MAMA (see Section 3.2.1
) control electronics were found on orbit to be subject to resets due to cosmic ray impacts, the MAMAs are operated only during the contiguous orbits of each day that are free of the South Atlantic Anomaly (SAA). We therefore limit the duration of any single MAMA visit (i.e., a single continuous observation series) to five orbits. Additionally, to facilitate scheduling and maximize the orbits available for MAMA observations, we require observers to split their CCD and MAMA exposures into separate visits. Specifically, for STIS programs containing both CCD and MAMA scientific (not target acquisition) exposures, in which there are more than 30 minutes of observing time using the CCD in a single visit (inclusive of overheads), and for which that visit requires more than a single orbit, you must
split the exposures into visits that separate the CCD from the MAMA exposures. Hence, this policy allows multi-orbit mixed visits with 30 minutes or less of total CCD scientific time, or single-orbit mixed visits regardless of the CCD/MAMA ratio. For programs that require
CCD and MAMA scientific exposures in the same visit (e.g., variability monitoring programs), exceptions can be made if you provide a well-justified explanation in the Special Requirements section of your Phase I proposal.