To:sot_shift from: Dan Schwartz date: 27 July 99, 0830 EDT Subject: SOT shift report, Shift A5 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii -------- Shift A5. Start at 208:03:30 GMT = 0930 pm 26 July 99 End 9:20am 27 July SOT Lead DAS Spac/Aspect RAC FOT/Sci liason EM HRC JG,EJ ACIS PPP,RB,EB,ES,PGF (Times will be given in GMT on day 208. In general times are rough, not precise.) PLAN Continue ACIS partial bakeout following big vent valve opening, and cool back down to -120 C. DONE Activate the USO (ultrastable oscillator). DONE Take a Vacuum Monitor measurement. DONE Maneuver & perform an IRU bias measurement. Test a Squirt patch to improve data quality to SI ESGE machines. EVENTS USO activation starts 0304. Switch to format 4. USO B active at 0317. 0334, return to format 2. Observe focal plane temperature at -49.4C, as before. Set ACIS focal plane temperature back to -120C at 0342. Execute CAP 75 to perform ACIS flight software dump. Focal plane is -70 C at 0433. Focal plane is -86.9 C at 0514 Focal plane is -97 C at 0558. Focal plane is -100.9 C at 0619. ACIS gives a GO for subsequent yaw maneuvers. Focal plane is -112.6 C at 0754. Focal plane is -115.3 C at 0834 Focal plane is -116.3 at 0850 Focal plane is -119.1 at 1000 Focal plane -118.9 at 1006 looks like it's bottomed out. Turn on vacuum monitor at 0602. Reads about 10^-4 as it settles. After an hour stabilization gives 9.3 x 10^-5. Turn off vacuum monitor and back on after 5 minutes. Stabilizes at same 9.3 x 10^-5 reading as before. Monitor off at 0727. After turning on and stabilizing, gives same reading. Power down at 0803. 1020, SSR dump. 10:50 fail-over to Squirt 2 to test patch. Early indication is that data dropouts are the same, but we should look for 12 hours to get statistics. Start yaw maneuvers at 1100. New OBSID, 62491, at roughly 11:30 Return to Format 4, 1200. NOTES/ISSUES/PROBLEMS Submitted flight note 92 to reduce ACIS bakeout time to 3 hours, in order to allow more cool down time before Yaw maneuver. Also established < -100 C as a firm requirement for focal plane temperature prior to allowing the maneuver. Typo in ACIS script cleared SCS slot 194 instead of 204. Will go ahead and disable and clear 204 as previously planned. The scripts I_1_SETFP_M120_A.ssc need to be changed to disable and clear SCS 204 (also for the B-side). OBSID 62798, originally planned for the ACIS partial bakeout, was uplinked about 01:05. The first part of the bakeout and the actual valve opening was done under OBSID 62991 as reported in the last shift report. RADMON procedure: Because we are at a low perigee we are getting RADMON high and low triggers which we will not expect in our final orbit. This causes undesired error messages in the OBC. (This was reported in B4 shift report, and is the result of diagnosis referred to in A4 report.) While at the lower perigee, we will be disabling the RADMON function prior to radiation entry and enabling it after radiation exit. The SOT Lead will need to confirm that HRC and ACIS are safe, and so report to the TST lead, prior to disabling RADMON, and to confirm the enabling of RADMON prior to reconfiguring HRC and ACIS after radiation belt egress. Abnormal switch from SSR-A to SSR-B had previously been observed. This is due to an inappropriate value of a parameter in the flight software. Until this PLAYBACK_TO_RECORD_LEAD_TIME parameter can be patched, the playbacks will be stopped manually to avoid having the playback pointer catch up to the record pointer. CAP 75 to dump ACIS flight software was not completely successful, because the software dump procedure had been revised to only dump 128 KBytes. We need to revise the procedure to dump the complete memory, and re-send. Orbital period is about 25h 37m 48s. ACA image slot 7 shows status bit #1 set ON all the time. This indicates a Defective Pixel. However, the image looks fine. The flag finally cleared after some 12 hours. (No change in image). The SOT ACA person on B shift should contact the Ball factory support to enquire about this situation. Have given up the Canberra pass at 208:12:30, because Goldstone has been extended. ACA sees a factor of three decrease in background current as X axis pitches away from the 90 deg sun angle. This is qualitatively consistent with the expected light leak which occurs with the SSD closed. ------------------------------------------------------- Dan Schwartz, MS #3 das@head-cfa.harvard.edu phone: (617)495-7232 FAX: (617)495-7356 cell phone: (617)512-5627 pager: 800-759-8352 PIN 1636502 or e-mail 1636502@skytel.com -------------------------------------------------------