SSOC Tohban Report for Week 23 (4-Jun-2001 to 10-Jun-2001) SSOC Tohbans : J. I. Khan, Y. Suematsu KSC Tohbans : M. Higashiyama, Y. Saito 0. Meeting Attendees J. I. Khan, T. Kosugi, D. E. McKenzie, M. Miyashita, Y. Ogawara, A. Takeda, T. Watanabe, K. Yoshimura ------------------------------------------------------------------------------- 1. Solar Activity Solar Activity increased from the previous week. There were 4 GOES M-class flares and many C-class flares last week. The GOES background level increased from the B to C level. ------------------------------------------------------------------------------- 2. Standard Operations 2.1 SXT Table Uploads The following SXT tables were uploaded: JST Day UT Start Time Pass Table ID ================================================================= Monday PM 4-JUN-01 09:29 4 010604 P4 ARS1 DRK W Tuesday PM 5-JUN-01 04:24 1 010605 P1 ARS1 DIF W Tuesday PM 5-JUN-01 09:29 4 010605 P4 ARS1 STD W Wednesday PM 6-JUN-01 04:23 2 010606 P2 ARS1 STD W Thursday PM 7-JUN-01 04:23 2 010607 P2 ARS1 STD W Friday PM 8-Jun-01 04:23 2 010608 P2 ARS1 STD W Saturday PM 9-Jun-01 04:23 2 010609 P2 ARS1 STD W ================================================================= 2.2 STT Timer Setting The STT timer set was done during pass 2 (Pass ID : 010605-0413) on Tuesday 05-Jun-01 and again on pass 2 (Pass ID : 010607-0309) on Thursday 07-Jun-01. Because of the eclipse of Canopus the STT timer was stopped during pass 1 (Pass ID : 010608-0206) on Friday 08-Jun-01. ------------------------------------------------------------------------------- 3. Special Operations 3.1. ACS: FAQ (fine acquisition) The ERR-Z value was found to have increased to more than 1.7 degrees during the KSC passes on 6-Jun. From 5-June 15:08 UT to some time between 6-Jun 22:16 - 23:10 UT, the S/C attitude was disturbed. The Z-axis rotated to a max. of about 2.4 deg and the X-axis (solar NS direction) was in a limit cycle swinging with an amplitude of about 20 arcsec. Control Momentum Gyros (CMGs) were saturated and did not produce proper torques perhaps due to a sudden increase of atmospheric disturbances along the orbit, though we had only four M-class (three M plus one almost M) flares on 4 - 5 June. The ERR-Z came down to 1.15 deg at pass 010607-0206 with no M-class flares on 6-June. No changes nor malfunctions were found in the IRU-gyrod, STT, and CMG hardware, but we changed the ACS control mode to "FAQ (fine acquisition)," during pass 010607-0309. The FAQ mode uses MW (momentum wheel)s and MTQ (magnetic torquer)s as actuators instead of CMGs. The ERR-Z quickly reached almost zero during the same pass. We decided to use the FAQ mode during the current eclipse period of Canopus, and return to NOR (normal) configuration thereafter. ------------------------------------------------------------------------------- 4. Errors and Problems 4.1 SXT Errors Bitmap errors: 010604-0516 This error was found and cleared during the same contact pass. 4.2 DP Errors None. 4.3 BCS Errors None. ------------------------------------------------------------------------------- 5. NASA Station Schedule 5.1 Contact Pass Cancellations/Additions The following schedule changes occurred: =============================================================== Week Schedule Changes =============================================================== Real-Time 23 2 cancellations Final 24 2 cancellation & 8 additions (of 13 requested) Preliminary 25 0 cancellations & 14 additions requested Strawman 26 51 cancellations =============================================================== 5.2 Contacts this week and next (see 8.12): Week Wallops Santiago Goldstone Canberra Madrid NASA Japan 22 30 0 6 1 4 41 33 23 29 0 5 1 0 35 32 5.3 Data Transmission from NASA Ground Stations ----(Copied from /home/flare1/yohkoh/dsn_corrupt/2001/01_23)---- 141 16 0835 corrupted requested 28-May Closed/ correct data 140 16 1135 not received requested 22-May no response requested 24-May Closed/ same data 143 16 0813 corrupted requested 04-Jun Closed/ same data DOY-151 G16 0450 - 0501 : 14237 blocks Late TLM lock on SOLA data. Antenna oscillating in "AUTO MODE". TLM in solid lock @ 045600z. Problem corrected when antenna was placed in "PGM MODE" and bias best of 0 was entered. DOY-153 G16 0308 - 0320 : 6455 blocks Acquired spacecraft out of keyhole. Had probolems acquiring the main beam. DOY-154 G16 0308 - 0320 : 17816 blocks Had problems acquiring the downlink main lobecoming out of keyhole and the autotrack system was not maintaining a solid track. Reverted to Program track mode. ------------------------------------------------------------------------------ 6. KSC Pass Conflicts and Schedule No conflicts No conflicts ------------------------------------------------------------------------------ 7. Hikitsugi Items 7.1 Tohbans for Next Week SSOC Tohbans: R. Kano, M. Miyashita KSC Tohabns: Y. Saito, A. Asai 7.2 STT Timer Setting The STT Timer Setting will be due pass 5 on Wednesday 13-Jun-2001 (JST). 7.3 Please continue to take STT MAP every day (see 8.10). 7.4 Holiday Schedule (KSC 34m antenna Tel: 0994-67-3152) The next holiday is 17-June-2001 (JST). The 34m-antenna operation is scheduled for Pass 1 (08:17 JST) and Pass 4 (13:21 JST). 7.5 CMD Operation Test for KSC 34-m antenna system CMD Operation using KSC 34-m antenna will be done at pass 1 (23:18 UT) on Thursday, pass 2(00:58 UT), and pass 3 (02:40 UT) on Friday, 15-June-2001. 7.6 New 26m Equipment for Yohkoh We received email from Ida Millner @ GDSCC @ NASA to advise us about the transition to new 26m equipment for Yohkoh which will start sometime after DOY 215. Yamada-sensei at ISAS will handle the consultation related to these changes. Future SSOC tohbans should keep an eye on the station identifiers in the schedules we receive from DOY 215 to check for possible software modifications which may be necessary if these change. > From: Millner, Ida > Subject: OPD-SOLA-001: Transition to 26M New Equipment for Solar-A (SOLA) > > 1) PURPOSE: > To advise the supporting stations of the transition to the 26M new > equipment for Solar-A. > > 2) EFFECTIVE PERIOD: > Upon receipt through DOY 215, when another OPD will be issued or a PCN > supercedes this OPD. ------------------------------------------------------------------------------ 8. Unchanged Hikitsugi Items from Previous Weeks: 8.1 DSN Pass Additions (2000-w20; modified 2001-w10) >>>>>*** DON'T FORGET TO REQUEST PASS ADDITIONS!!! ***<<<<<<< Yohkoh loses DSN passes as follows: (1) Canceled by the SSOC tohbans (2) Deleted by DSN The Tohbans SHOULD COMPARE the STRAWMAN, PRELIMINARY and FINAL schedules for each week to see if some of the passes lost by case (2) could be replaced by ones from case (1). -------------- Thus it may be possible to request pass additions for the PRELIMINARY and FINAL week schedules from the [case (1)] STRAWMAN cancellations. Only request additions from the crossed out cancellations done by SSOC. The routine to use is ADD_DSN: e.g., IDL> add_dsn, 28, /prelim IDL> add_dsn, 29, /final Decide on the complete list of passes to be added and select them like CANCEL_DSN. Then ftp and email the appropriate file. 8.2 Weekend Terminators If possible, please schedule terminator opportunities on any weekend table (i.e., if room permits). 8.3 Software Problems PR_GEV with /hc keyword produces a temporary output file but does not print it at the printer. 8.4 OP_FIRST_GUESS Problem (1)(1999-w38, 1999-w45) In a situation with two KSC cancellations on each of two days (a rare condition) the BDR optimization feature of OP_FIRST_GUESS crashed. After experimentation, we found that it ran OK without the final cancellation request (two the first day, but just the first one on the second day). The second one then had to be removed manually. Records of the problem were forwarded to Lemen-san, but no answer had arrived at the time of writing. (2)(1999-w46, 1999-w45) During the preparation of 991109-1238 OP, 991110-1135 OP and 991111-1032 OP OP_FIRST_GUESS crashed with the message "OP_START_END: problem with detection of LOS/AOS/DSN Repro events". This problem was solved by changing OP_FIRST_GUESS options: choose optimization 1 rather than 2. (3)(2001-w06) OP_FIRST_GUESS frequently got confused about start times, trying to read weekly files extending forward years from the present. Re-tries eventually worked. 8.5 Keeping Wallops Contacts (1999-w42, 1999-w45) This is not a new policy, but to emphasize (paraphrased from e-mail from Hugh Hudson): We should keep all valid Wallops passes, independent of day/night status, in order to maximize our Wallops use and minimize our DSN use. NASA won't give us many DSN passes anyway, so if we select a Goldstone pass in preference to a Wallops one, we'll normally just lose both. Another reason is that CANCEL_DSN software needs some repair, since it seems to replace the DSS identifier WGS with 0. This is likely to cause confusion, but of course if we don't cancel Wallops passes we won't have this problem often. 8.6 34m ANT Operation (2000-w33, 20001-w12) 34m Operation will be done only on Sunday (=Yohkoh holiday) for up to 2 or 3 passes. There will be no 34m OP to compensate for the lost pass due to the conflict with the other satellites. For further details, please ask Kosugi-san. Note that 34m operation requires more CE slots in OP table than DSN operation does. Weekend OP cannot accommodate many 34m passes without sacrificing even more DSN passes. Also, max elevation of the 34 m antenna should be checked carefully using Weekly Visible Diagram (do not trust op_first_guess nor AOSLOS listing). Try to avoid zenith passes ( Max. El. >76 degree) in planning. However, do not try to change the already fixed schedule just because the pass chosen turns out to be a zenith pass. There's no problem using the zenith pass with extra few op commands. (2001-w12) 8.7 Weekend DSN passes (2000-w49) We used to schedule 12 DSN passes during the weekend, but now we have two passes with the KSC 34m antenna. So only 9 or 10 DSN passes should be scheduled for the weekend. Please be sure to cancel extra passes as early as possible. 8.8 DSN Max Elevation DSN max elevation must be higher than the following value: Contact Max El.(degrees) Madrid 10.0 (2000-w45) Santiago 13.5 (2000-w44) Wallops 6.5 Others 7.0 8.9 OP and SXT Table Transfers Trouble (2000-w34) OP and SXT tables can not be transferred to KSC correctly when the MS computer at ISAS is in Initial Program Load(IPL). HALCA groups operate the satellite from ISAS. SSOC tohbans must be careful to transfer OP and SXT tables in the following periods, an hour before the beginning and an hour after the end of HALCA contact. As for IPL of MS computer at KSC, operators confirm if new OP and SXT tables come to MS computer at ISAS after the IPL. 8.10 STT MAP operation in OP (2000-w42, revised at 2000-w53, 2001-w08) If possible, please schedule the STT MAP operation just before the 1st KSC Pass on next day. The OP commands to be inserted in OP are as follows; OG-030(DEC) CMPN OBS ON OG-035(DEC) STT EVENT OFF ; 1 step after CMPN OBS ON OG-117(DEC) STT MAP START ; 1 step after STT EVENT OFF OG-118(DEC) STT MAP END ; 5 min (10steps) after STT MAP START OG-036(DEC) STT EVENT ON ; 1 step after STT MAP END OG-031(DEC) CMPN OBS OFF ; 1 step after STT EVENT ON Please insert these command manually in OP schedule. The timing of these commands must be assigned around the mid-time of Canopus tracking window (note that the Canopus tracking does not work normally in this window). It is prefer that the command work during the night period of the satellite. The Canopus tracking window appears on the AOSLOSGD plots as a dotted line. It is preferable to schedule the 10 steps contiguously (as shown, avoiding mode switches). 8.11 Bug-fix Report about the Attitude Determination Software (ADS) at 200-w53 Related with the Y2K problem, a software bug was found in the attitude detection software. The problem occurred in the procedure to search the orbital element file. In the program including the bug, the attitude of the Yohkoh satellite was calculated using the latest orbital elements in DASD or Sirius database, while it must be done using the elements of the day nearest to the observation date. This buf has been fixed now. This bug causes the large attitude error when the observation date and the calculation date of the attitude are largely different. From 2000 Jan. to 2000 Sep., there are 10 candidates with the attitude error greater than one minutes of arc, which are as follows (obs. date); 27-Apr-2000, 28-Apr-2000, 13-Sep-2000, 14-Sep-2000, 7-Jan-2000, 11-Sep-2000, 9-Mar-2000, 8-Jan-2000, 28-Sep-2000, 12-Sep-2000. Re-calculation of the attitude is scheduled to these 10 cases. 8.12 print_contact (2001-w07) It's helpful to see the actual statistics of the DSN/Wallops station passes. The program "PRINT_CONTACTS" does this for inclusion in the weekly report, e.g. IDL> print_contacts,[6,7] lists the passes for weeks 6 and 7. [end of report]