To:sot_shift from: Dan Schwartz date: 08 Jul 2011, 10:00 EDT Subject: SOT shift report 2011-07-08 L4369 -------- See http://asc.harvard.edu/acis/SOT_reports/sot-shift.html, or /proj/web-cxc-dmz/htdocs/acis/SOT_reports/Jul_08_2011_L4369.txt (NOTE NEW LOCATION FOR THE REPORTS DIRECTORY AS OF DEC 2010) Shift L4369. Start at 189:12:00 GMT = 08:00am 08 Jul EDT End 10:00am 08 Jul SOT Lead DAS (Times will be given in GMT on day 189.) PLAN ---- Continue analysis of safe mode and consider possible recovery steps. NOTES/ISSUES/PROBLEMS --------------------- We note the E150 rates increasing, and the E1300 rates decreasing, as EPHIN is getting very hot. This is the expected behavior. From the 9am status meeting: Three comms over the past day, no issues. Ran CAP 1192 to reset the SSR-A playback pointer. Playback successfully recovered the missing ~80 minute of data. Sun remains very quiet. SAFE MODE Status meeting ------------------------ A TWiki page has been set up, see http://occweb.cfa.harvard.edu/twiki/AnomalyResponse/JulySixSafeMode Current analysis shows that safe mode should not have been triggered based on the momentum calculated from telemetry of IRU, Reaction Wheels, and MUPS firings. BUT, values from the OBC calculation of momentum are not consistent with these TM inputs, and the OBC calculated values should have (and did) cause the delta-momentum monitor to fire. Check sum area of OBC-A code agrees with the ground image, so looking at values of constants to see why OBC-A calculated those spurious momentum values. Have obtained extended comm to 1505 currently, and from 1905 to 2245. Momentum is building up such that an auto-unload would (probably) be triggered by the CPE during next perigee. Instead, the plan is to stop the YAW bias and leave the spacecraft in position near to where it entered safe mode, so that momentum will cancel. Near Term Actions: Prepare a CPE patch to stop the YAW bias. Run a CAP to execute the patch at an appropriate time. Turn OBC-A on. Perform low level "aliveness" diagnostics. Consider what diagnostics we would need to do to have confidence to resume operation on OBC-A. Continue analysis of OBC dump to try to understand how it calculated large momentum change. Quick look data: NONE Next Comms: ----------- 1905 to 2245 then resume previous schedule 190/0045-0300 0145 0245 DSS-24 GOLDSTONE 2145-2245 EDT, Fri 8 Jul 190/1000-1215 1100 1300 DSS-24 GOLDSTONE 0700-0900 EDT, Sat 9 Jul 190/1840-2055 1940 2040 DSS-65 MADRID 1540-1640 EDT, Sat 9 Jul 191/0015-0230 0115 0215 DSS-24 GOLDSTONE 2115-2215 EDT, Sat 9 Jul 191/0900-1115 1000 1100 DSS-24 GOLDSTONE 0600-0700 EDT, Sun 10 Jul 191/1635-1850 1735 1835 DSS-24 GOLDSTONE 1335-1435 EDT, Sun 10 Jul 192/0240-0455 0340 0440 DSS-24 GOLDSTONE 2340-0040 EDT, Sun 10 Jul 192/1000-1215 1100 1200 DSS-65 MADRID 0700-0800 EDT, Mon 11 Jul SNAPSHOT summary ---------------- Status at LOS, 189:14:49 was as follows: EPHIN Geom = VLD E150 = 1736 800000 (RADMON E1300 = 0 1000 Triggers) MPC = 30 ANTI-CO = 245 Descending through 111971 km. ACIS focal plane temperature -119.9 degC. EPH temp: 138.67 degF