Just thinking out loud, what would the endurance be with just supply tanks feeding the engines? I.e. From full to engine out. Both Xfer pumps as we know we're off, what I'm thinking is if the accident time of 22:22 minus supply tank only endurance aligns with a key point, maybe transition from cruise to the first observation task or non urgent orbit task.
FS
Sorry Sky, was writing this whilst you posted!!