UVCS MISSION LOG ---------------- Date: 27 July 2001 ----- Last revision: 01 August 2001 (Wu) -------------- File Name: 2001.07.28.a.log ----------- Compiled by: M. Uzzo, R. Wu ------------ UVCS Activity: Mid-latitude Coronal Hole Study for 28 - 29 July 2001 -------------- UVCS transitions to SAFE mode due to SOHO ESR SOHO Activity: SOHO goes into ESR at 20:16 UT -------------- EOF Staff: M. P. Miralles: Lead Scientist ---------- M. Uzzo: Planner, Commander R. Wu Command file: 01.07.27.13:45:51.cmd.log Activity: --------- 1) Observation of High-Latitude Coronal Hole Sequence: 01.06_hole1.tcl SCI_SPEC: Characterization of a mid-latitude coronal hole. Goal is to measure the properties of a mid-latitude coronal hole. In particular we are interested in the coronal conditions (intensities and line widths for HI Ly-alpha and OVI 1032/1037) as a function of height and latitude. We will compare these properties with the ones found in polar coronal holes. Roll positions are VL-corrected for PA=24 degrees. OBS_PROG: Primary: Sensitivity Sub Obj: Spatial Coverage SCI_OBJ: Plasma Properties...Proton and Ion Temperatures OBJ: Coronal Hole CMP_NAME: CMP_NUM: Duration: start: 2001.07.28.18:40 end: 2001.07.28:20:11 ONUMs = 16473 (27 exps) ; aborted due to SOHO ESR 16473 (1 exp) ; leftover exposure left in buffer during ESR 16474 (36 exps) ; not run Instrument configuration: - Pointing: Sun center - Roll: 16.09, 17.27, 18.38 (21691, 21906, 22108) - Mirror/Occulter: 1.7, 2.0, 2.4 Ro 1.5 mm overocculting - LYA Slit: 50 um - OVI Slit: 50, 75 um - LYA GRTPOS: 128000 - OVI GRTPOS: 168208 - LYA mask: LYA_93_1sec in slot 2 - OVI mask: OVI_168MPM in slot 1 Fits Files: q01.07.28.18:32:08.lya.dat q01.07.28.18:32:08.ovi.dat q01.07.28.18:32:08.vld.dat q01.07.28.20:11:56.lya.dat q01.07.28.20:11:56.ovi.dat q01.07.28.20:11:56.vld.dat 2) UVCS in SAFE Mode Resultant from SOHO ESR at 20:16 UT 28 July 2001 Sequence: SCI_SPEC: UVCS Door Closed, Substitution Heater (Circuit #84) on to 60% duty cycle per standard ESR, Mechanism power is on, Detector power is off. Information from SOC (from email "SOHO ESR Summary and Status per 16:30 UT July 29"): SOHO entered ESR after an ACU reset caused by a watchdog detection at 20:16 UT, July 28. At the time, we had a normal pass with DSN 27. In order to improve the commanding capability, at 20:33 UT a spacecraft emergency was declared and at 21:00 UT we got DSN 34. The roll rate, which was between +0.15 and +0.20 deg was reduced to +0.08 with two thruster firings. The transition to CRP mode was completed on July 29 at 3:35 UT, and at 3:37 UT the spacecraft emergency was lifted to release DSN resources. As of 14:00 UT today, SOHO is in CRP mode and FDF has determined that the current roll attitude is +162.3 degrees. Target roll angle is +4.59 degrees. Therefore, a roll manouver of some -158 degrees is required. This will take about five hours. FDF has also determined that there is no need for a momentum management previous to the recovery roll. Because we have a gap in 34 meter coverage today (D24 is scheduled from 13:45 to 21:20 and D34 from 22:40 until 06:00 tomorrow) it has been decided to do the COMS backup first (two hours) to go to medium rate, being able to use 26 meter stations and, keep the roll maneuver going during the 34 meter support gap. After the roll there will be a momentum management with a burn time of two hours approximately. Also, later on, there will be a station keeping maneuver that will push the need for the scheduled one from early October, as it was planned, to December or later. When the station keeping will take place is not know at this time. There are a lot of constraints with DSN tomorrow, with one of the GOES spacecraft having problems, the launch of Genesis and MAP lunar swingby, so some activities might be postponed for later in the week. All instruments are safe. Medium rate telemetry is expected about 16:45 UT. It will take another 1 1/2 hour before the roll can be started. NRT for instrument checkout will then be available during the roll. Additional info from SOC (Mon, 30 Jul 2001 01:23:06 GMT): FYI: Genesis launch has been delayed a minimum of 24 hours. It was originally scheduled for Monday at 16:36 UT. Tonight: One momentum management segment until 02:00 UT. (WIND needs DSS-34 after 02:00 UT for data retrieval) Monday: Second and Third momentum management segments starting at 08:30 UT (4:30 a.m. EDT). We have DSS-66 07:55-11:40 UT DOY 211 DSS-27 18:25-01:50 UT DOY 211 Stationkeeping plans have not been set yet. OBS_PROG: SCI_OBJ: OBJ: CMP_NAME: CMP_NUM: Duration: start: 2001.07.28.20:16 end: 2001.07.31.17:36 ONUMs = N/A Instrument configuration: - Pointing: Sun center - Roll: 17.20 (21899) - Mirror/Occulter: 2.0 Ro 1.5 mm overocculting - LYA Slit: 50 um - OVI Slit: 50 um - LYA GRTPOS: 128000 - OVI GRTPOS: 168208 - LYA mask: LYA_93_1sec in slot 2 - OVI mask: OVI_168MPM in slot 1