SSOC Tohban Report for Week 05 ( 31 JAN - 07 FEB, 1994 ) Sterling, Ishido (SSOC) Kozuka, Shimizu (KSC) 0. GENERAL Operations were basically normal. Several DSN passes were cancelled on short notice due to NASA support for the DPSE and Shuttle missions. 1. Solar Activity Solar activity was moderate during the week, with some C class flares on 3-Feb. There was also a long-duration B class "event" on 31-Jan. 2. Standard Operations 2.1 SXT Table Uploads Pass ID (Tue.) 940201-1033 "940201 T1 P4 ARS1 DKCAL" (Wed.) 940202-0826 "940202 T1 P2 ARS1 STD+LONG" (Thu.) 940203-0824 "940203 T1 P2 DEEP CORONA" 940203-1031 "940203 T2 P4 ARS2 STD+LONG" (Fri.) 940204-1031 "940204 T1 P4 ARS1 LNG+DIFF" (Sat.) 940205-0722 "940205 T1 P2 ARS1 STD+LONG" 2.2 STT Timer Set The STT timer was set twice last week, pass 940201-0826 and pass 940205-0825, and is to be set again during pass 940207-0620 tonight. It will have to be set again on Tuesday, 8-Feb. 2.3 Offset pointing The 8' east/west offset pointing was done from pass 2 to 4 on 3-Feb. (Thu.) 3-Feb #2 (940203-0824) east 8 arcmin (ROG #23h) (Thu.) 3-Feb #3 (940203-0927) west 8 arcmin (ROG #24h) (Thu.) 3-Feb #4 (940203-1031) normal point (ROG #20h) 3. Special Operations The request for special operations on 6-Feb for H-II support was cancelled by NASDA. 4. Errors and Problems 4.1 BCS errors 31-Jan. SEU found during pass 940131-1032. Recovery was first attempted during pass 940131-1135, but was halted because of unexpected circumstances arising during the recovery. After consultation with Watanabe san, the recovery was redone and successfully concluded during the following pass (940131-1239). Later, Watanabe san found that the "unexpected circumstances" during pass -1135 resulted from KSC tohban error in implementing the recovery (BCS MEM H inadvertently sent twice). 4.2 SXT errors None 4.3 False Flares Several false flares were seen during the week (from data from passes of 940131, and from passes 940202-1137 and 940204-1135 at least). At least one of those (31-Jan, 18:40:26 - 18:48:17 UT) occurs near the end of an SAA. Is it possible that the modifications made a few weeks back to the HV reduction on and off times are too severe? (Incidentally, Louise Harra san notes that BCS data also indicate that the HV flag may be being turned on too soon following SAAs -- e.g., data from 940201 show this effect). [It was decided at the 7-Feb Monday meeting to let this issue ride for a while. The increase of the false flare rate may be due to the apogee of Yohkoh being in the SAA.] 4.4 DSN Interaction 4.4.1 Missed Passes DSN called and FAXed us on 1-Feb asking about data they expected, but did not receive from Yohkoh during two DSN passes, DOY 32, 04:00 and DOY 32, 05:43. Their major concern was that there may have been a problem with the satellite, as "it is not like [the Yohkoh Team] to miss two consecutive passes...." It turns out that those two passes were the ones requested as real-time additions by the previous week's tohbans. Those tohbans did NOT, however, receive any notification of the additions of the passes, and the RASM final schedule was not changed as of a few hours before the OP was uploaded. Therefore, those two passes were not included in the OP uploaded the evening of 31-Jan. ACS talked by phone with Matt Boyd regarding this matter. According to Matt, the requested additions (by the previous week's tohbans) were added to the week 05 final schedule at 12:12 UT on 29-Jan. (That was within about 12 hours of the request.) Checking the files that were currently in the RASM directory showed that there were three week 05 final schedules there. There names were: solass.w05;2, solass.w05;3, and solass.w05;4. Examining these files, we found that they were created by DSN on 28-Jan, 09:23; 31-Jan, 22:53; and 01-Feb, 00:46, respectively. There was NO file listed as being created on 29-Jan, 12:12. We sent a FAX to Boyd san giving this information. ACS again talked with Boyd san on 2-Feb. He verified that he had received the FAX, and was looking into the matter on their side. He said that it seems as if there is no problem on the ISAS side. As of week's end, we had not yet received any further notification about this matter from DSN. A general recommendation by Boyd san was that the tohbans notify DSN via FAX or RASM mail if they do not get a response from DSN when expected. For example, if the tohbans do not hear from DSN after a few days regarding requests for pass additions, and if the RASM final schedule has not been changed, the tohbans should send DSN a FAX (or RASM mail) asking whether or not they are expecting downlinks at the requested times. 4.4.2 'Ikinari' Pass Cancellations Matt Boyd called again on 2-Feb to inform us that two DSN passes scheduled to be uploaded that night were to be cancelled. That meant modifications to that night's OP. The reason was a 24 hour delay in the burn to inject DSPE into a lunar trajectory. He also warned us to be on the lookout for additional pass cancellations over the next few days. 5. Other 5.1 English Tohban Manual and Checklist ACS updated the English Tohban Manual and Tohban Checklist. The Manual now includes instructions for performing the STT Timer Check. Most other changes were minor. Users should be alert to note any important changes or additions on page 2, at the appropriate location in the text, and in an EMAIL message to the address on page 1 of the manual. 5.2 DSN Data Tests A week or two ago Ogawara san asked whether or not DSN is still doing checks on their new telemetry system. A mail message from Jim Lemen to Wendell Keller (with a copy to the Yohkoh account) of 1-Feb indicates that such tests are still underway. Lemen and Kosugi san-tachi can be contacted for more details. 6. Hikitsugi The first OP that the new week's tohbans will have to prepare will be Tuesday night's. BUT, they should check for FAXes from DSN, and they should check the mail on the Flare 1 Yohkoh account, as there may be last minute DSN cancellations to take care of for the Monday night OP. SXT may do a table upload tonight (Monday) during pass 4. Check with Acton san. Add the table upload commands to the command sheets if necessary. The STT Timer set is already prepared for Monday night's operations. It will have to be reset again during Tuesday night's operations (8-Feb). The next tohbans in week 06 are * SSOC Yoshimura, Yokoyama * KSC Kozuka, Shimizu Good Luck!!