Aor 06, Telecom -------------------------------- The SCS 107 shutdown at 096:00:59:16 was apparently due to electron contamination of the P4 channel, due to the "puffed up" radiation belts which we have encountered the two previous years at about this time. At the radiation telecon we agreed to apply a more conservative criterion for entering the radiation belts; namely, to configure for the belts 13 hours prior to perigee passage. This is the criterion we ultimately used successfully last year. We lose about 3 hours, or 10ks of what would be good observing time IF we didn't encounter the excess electron fluxes. Besides providing a conservative criterion against false trips, this extra time will be used for longer ACIS CTI observations, and for manuevering which can help in the overall thermal and momentum management.