Satellite constraints

Exposure times for individual pointings can not exceed the time between ground station contacts, which are expected to occur every 18 - 30 hours. Although, in principle, there is no lower limit to the duration of individual observations, the number of satellite pointings between ground station contacts will be limited to $\sim$ 10, so only a small number of very short pointings can be accomodated between any two ground station contacts. It will be possible, however, to make raster scans of short duration within a single pointing.