SSOC Tohban Report for Week 12_95 (20 Mar - 26 Mar 1995) SSOC: Hudson, H., Khan, J. KSC : Koide, S., Koyama, 1. Solar Activity ----------------------------------------------------- Activity was not low. Phenomena included a CME on 21 March (E limb) and an M2.4 flare on 22 March. The latter was at an unspecified location so it might have been over the limb. 2. Standard Operations ------------------------------------------------ 2.1 SXT Table Uploads : 2 times --------------------------------------------------------------------- KSC Time (start) Pass# Table ID --------------------------------------------------------------------- 950322 P4 ARS1 DARKCAL 950323 P4 ARS1 STD+LONG --------------------------------------------------------------------- 2.2 STT Timer Setting The STT Timer was set on Pass #4 on (Tue) 21-Mar and disabled on Pass #4 of 23-Mar because of Canopus eclipse. The next setting will need to be on Tuesday, 28 March. The STT stop was confirmed. 3. Errors & Problems ------------------------------------------------- 3.1 SXT and BCS errors. A BCS error was detected on Pass #3 (the first KSC pass) of 25-March, and was successfully recovered on Pass #4. An SXT error (SEU) was detected on Pass #4. There was no opportunity to carry out a recovery, so SXT was left in the error state over the weekend. 3.2 Deletion of Strawman Schedule for W14 Skinner_san of ASCA and Hudson met on Monday and reconciled the ASCA/Yohkoh DSN conflicts. There were 49 cancellations from the strawman for week 14, which may be a new record. 3.3 JPL report problem There was extensive fax negotation with DSN about re-sending one pass (from Wallops) for which ASCA and Yohkoh were mislabeled. 3.4 Terminator image scheduling As agreed, we have not been scheduling terminator images during the` KSC operations interval. Luckily there were very few KSC passes so we could get more terminators. OP_FIRST_GUESS should install this as a new rule. We suggest that the system be changed in the following way. We lose terminator opportunities because they are not done during medium rate telemetry. Could we change the policy and put Yohkoh in Quiet High for the single SXT exposure? This could be scheduled automatically in OP_FIRST_GUESS. The negative impacts would include the following: (a) the data streams of other experiments would more complex (b) the SXT table would reset upon re-entry to Quiet Medium (c) two extra OP slots would be needed for each instance. In spite of these issues, this procedure would expedite the collection of the terminator data base, which is operationally difficult. 3.5 Operations errors of 23 March The SXT TBL RE command was not successful and "table mismatch" condition occurred in SXTSPT. At this time the table comparison was being done at SSOC because of manpower problems at KSC. In spite of the lack of table confirmation, the SSOC tohban approved the operation in order to be sure that the succeeding commmands (STT disable) were done properly. On this day Yohkoh had only two station passes because of SFU competition. In the condition resulting from the SXT TBL RE error, SXT CTL MAN restored SXT to operation even though ACS MOD H had been issued and it was night. The result of this operations error was to leave SXTSPT in a mismatch state. The tohbans confirmed by looking at the data dumped on pass #5 that SXT operation was correct after the fact. An alternative and more conservative approach would have been to issue the SXT HALT command on pass #5, but SSOC decided against this. 3.6 Operations errors of 24 March Serious operational errors took place on 24 March. The pass schedule that had been agreed upon with SFU and ASCA called for three passes. Approximately one hour before pass #3 (ie, the first pass and the one with the OP upload), the SFU operators called to request this pass, and Yohkoh complied with this request. Upon completing the preparations for the operation on pass #4, they faxed the comand sheets and went to dinner without having completely confirmed the preparations at KSC. This was a grave mistake given the manpower situation at KSC. The fax was in fact not received, and the KSC tohbans therefore had no operations plan for pass #4. This resulted in several mistakes. One of these was that SXT was left in CTL MAN for the succeeding orbit. Another was that the OP, which was loaded towards the end of the contact pass, was started about 50 sec late. The situation was recovered on pass #5 after consultation with Kano-san and Kosugi-san. The OP was restarted with the correct timing from the NOP for that pass. 3.7 Operations problems of 25 March On 24 March, during the revision of the SFU schedule conflicts, it was found that the first two Yohkoh passes did not have to be cancelled after all. A verbal request was made from SSOC to KSC as to whether these passes could be supported, and the answer was "yes". Accordingly this plan was carried forward. However on 25 March, the answer turned out to be "no" and so the plan needed to be revised. This necessitated once again learning how to turn on SSOC#2, but this would have been necessary in any case because of DSN support changes. 4. DSN Communications ------------------------------------------------------ 4.1 DSN Strawman Schedule for W15 Skinner_san reported on 24-March that there were no DSN conflicts between ASCA and Yohkoh in Week 15, and accordingly the Friday meeting was cancelled. Perhaps the Wallops station is helping that much? SSOC cancelled 22 passes from the W15 strawman. 4.2 DSN Forecast Schedule for W14 There were no cancellations needed from the Yohkoh side. 4.3 DSN Final Schedule for W13 There were no cancellations needed from the Yohkoh side. 4.4 Wallops station The Wallops station passes are still being entered manually, requiring the tohbans to study the OP_FIRST_GUESS rules more carefully. We wish the AOSLOS program would be modified to interleave the Wallops station passes in the near future. The Wallops station access is very helpful. 4.5 Pass added The weekend OP turned out to have a telemetry gap of more than one day, as a result of the sudden loss of four DSN passes. Accordingly SSOC faxed a request for "one or two" of these passes to be restored. The fax went to DSN real-time operations, and the result was that Yohkoh got one pass back, as notified in RASM. This weeks tohbans feel that tohbans should not be shy about requests like this in difficult situations. 4.6 Huge numbers of cancellations We seem to be in a bad patch for cancellations of DSN coverage initiated by DSN. For example, for Week 13 the final schedule of 25-March shows only 20 passes all week! The preliminary schedule had shown 40. We speculate that some of these are going to SFU, but who knows. If so, would it be in any way desirable for ISAS to take over the management of all three (ASCA, SFU, Yohkoh) as a unit, rather than leaving it for DSN to do? 5. YOHKOH/ASCA/SFU Pass Conflicts at KSC ---------------------------------- In week 12, we lost many passes due to the SFU launch. The ASCA project has been quite accommodating and the ASCA conflicts, which are at the end of the sequence rather than the beginning, have not added to our losses. Nevertheless we have had severely truncated operations (only two KSC passes on Monday and Tuesday). Week 13 looks much better. The SFU orbit is drifting out of the Yohkoh window, and the orbit adjustments are almost complete. There appears to be a phase difference of about half a pass per day, so there is an odd-even pattern in the conflicts. Thus even with ASCA and SFU both competing, Yohkoh has two "normal" days of 5 KSC passes in Week 13. There will be a conflict resolution meeting on Monday and also at the usual time (with Nagase_san) on Thursday. Until the situation really is stable, we should check frequently to avoid problems of communication such as those that happened in Week 12. 6. Special operation There were no special scientific operations. 7. Holiday Schedule -------------------------------------------------- Holiday wil be Sunday, 2 April. 8. Photocopier There is a new photocopier. The SSOC tohbans from Week 12 were able to complete its installation by removing bits of plastic from the inside, so that it can now do two-sided copying. ************************************************************************** 8. Hikitsugi Items -------------------------------------------------- 8.1 Tohbans for Week 13 KSC : N. Kobayashi and Te. Watanabe SSOC : Y. Hanaoka and H. Tonooka 8.2 SFU pass conflicts (KSC) Please consult Tanabe-san or Murakami-san of SFD regarding pass conflicts with SFU for Week 14, and then regularize the conflict resolution for all 3 satellites at the regular Thursday meeting with Nagase-san. 8.3 STT timer setting The next STT timer set is due on Tuesday, 4 April. 8.4 Terminators. Do not schedule terminators (ie, delete them manually) from the KSC contact interval if they should be scheduled there by OP_FIRST_GUESS. We are doing offpoints on each terminator opportunity. Please consult with the SXT chief observer for how this works, and refer to examples in the OPs from Week 12 for guidance in how to schedule the images. We are using the following offpoint OG's and are going through them in sequence cyclically. That is, change each time to the next number please: OG 34 S/C W19 S01 (all OG numbers are decimal) OG 35 S/C W10 S01 OG 36 S/C W04 N00 OG 85 S/C W03 N02 OG 86 S/C E04 N00 Do not use OG's 33 and 87 until we clarify the safety issue. ************************************************************************** 9. Other This morning we were informed of the tragic news that one of this week's KSC tohbans, Koyama-san, passed away. It seems there was some kind of accident, but we have no details on the matter. We extend our deepest sympathy to Koyama-san's family. **************************************************************************