July_30_1999_B.txt Shift B8. (Times will be given in GMT on day 211-12. not precise.) Start at 13:20 GMT = 9:20am EDT 30 July 1999 End 9:19pm EDT 30 July SOT Lead Ed Kellogg Spac/Aspect Tom Aldcroft FOT/Sci liason Andy Northrup HRC Gary Meehan,Kathy Daigle ACIS Yousaf Butt PLAN ---- Continue ACIS internal calibration Diego checkout ACIS/HRC radiation entry ATS to safe SIs Longer IRU bias dwell for FN 127 Slosh Test 1A Patch inertia tensor K const to both OBCs, Caps 104/106 Earth scan 14 Continue monitoring ACA fidlites EVENTS ------ 13:00:36 ionizing radiation hit caused loss of fidlite in slot 5. This was unique in that it happened eight hours before perigee, whereas the one that happened on 207:1729 was at perigee 3 + 2 hrs, and the other two were within ~ 1/2 hr of perigee. Thus, these losses of tracking in ACA are not just associated with perigee at our present low altitude, but can be expected to occur in the final mission. 15:17 ACIS finished internal cal source measurement. Did not use OBSID 62772 because one test, 3x3 graded on S detector, was skipped. 15:45 HRC shut down by ATS. 15:53 Pitch to 35 degreee sun angle. 16:00 ACA background bright, lost 3 out of 4 fidlites. 21:30 Perigee #7. Lost one fidlite. NOTES/ISSUES/PROBLEMS --------------------- For monitoring EPHIN, Mike Juda can't always be here and we need an alternative person. We had Eric Martin train Tom Aldroft a bit today. Tom believes that changes are needed to the ACA software to prevent it moving the tracking box so quickly when we have an upset event. Also, it always appears to move the image to the edge of the box, which is not surprising when you think of it, since a random event occurs more often near the edge than the middle because there is more area out by the edge. Tom will pursue the software issue with Ball. See flt note #142. ACIS pulse height spectrum, cf http://space.mit.edu/HETG/flight/obs/acisf049710451N000_evt1_TDET_showselect.gif, shows Fe55 Kalpha and Kbeta and Si escape peak. The version referenced above does not have the best gain map, so one should not take this as the best pulse height resolution possible.