tl;dr: Some misconfigured switches meant that rendezvous radar jobs kept being erroneously scheduled, which used up available memory. Whenever there was no more memory available, the alarm would fire and the computer was rebooted. It would immediately restart (resuming from near where they left off) all the high priority jobs (while not restarting the radar jobs), meaning that it could still land safely.
tl;dr: Some misconfigured switches meant that rendezvous radar jobs kept being erroneously scheduled, which used up available memory. Whenever there was no more memory available, the alarm would fire and the computer was rebooted. It would immediately restart (resuming from near where they left off) all the high priority jobs (while not restarting the radar jobs), meaning that it could still land safely.