ACE Weekly 11/12/04 - 11/18/04 All ACE spacecraft subsystems are performing nominally. No maneuvers were executed this reporting period. The next attitude maneuver is scheduled for 11/22/04. ============================================================================ Orbit Events: From Craig Roberts (FDF): The next ACE Solar Exclusion Zone transit has begun. ACE crossed the 4.75 deg mark inbound on 11/15/04, and will exit outbound by 12/09/04. As the ACE Lissajous orbit transitioned to an opening pattern mid-summer, we are now in an era where the Sun-ACE separation angle at closest approach will be greater with each successive crossing (for the next couple of years). This time the angular radius of closest approach (RCA) will be 0.83 degree (last time it was 0.31 deg (11/31/04)). More details below: 3.0 deg inbound: 11/20 02:17Z 2.0 deg inbound: 11/22 18:53Z 1.0 deg inbound 11/25 19:29Z 0.83 deg RCA 11/26 21:32Z 1.0 deg outbound 11/28 12:08Z 2.0 deg outbound 12/01 13:24Z 3.0 deg outbound 12/04 06:50Z ACE will spend 2.7 days below 1.0 deg. ===================================================================== OCRs Executed: None ===================================================================== Ongoing Activities: TAPS: - TAPS Release 4.3 was installed on the Prime System on 10/13/04. -- FOT regression testing is in progress. --- No problems to report. ---------------------------------------------------------------------------- Automation (ROBOTT): - ROBOTTv0.9 delivered to String 1 on 09/27/03 (OCR GND_145). -- Performing operations in "Auto" mode on String 1. -- 13 DR fixes in this release. --- 12 DRs have been verified by the FOT to date. --- The last DR to be verified will require ROBOTT to be observed over a period of time to ensure no reoccurrence of the problem. -- 13 DRs have been written against this release. - Lights-out weekend operations started 11/13/04. - ROBOTT FOT Test Summary Report ready for signature. - ROBOTT System User's Guide (SUG) (signed) received from Developers. ============================================================================ Extra Spacecraft Activities: DOY 04320 (11/15/04) Executed the procedure S_TLM_SECTIONS for SSR-B. THE SBE_CT_B increased from 608 to 858. The SCRUB_ERR_CT_B remains at 0. The last time S_TLM_SECTIONS was performed was on 09/22/04, the SBE_CT_B increased from 286 to 608. DOY 04321 (11/16/04) Execute the procedure S_TLM_SECTIONS for SSR-A. There were no new SBE's for SSR-A. ===================================================================== Anomalies: DOY 04320 (11/15/04) ACE Anomaly S04-0015 - Increase in SSR B SBE Count While scrolling through SSR B's 30 telemetry sections, the FOT noticed that the SBE_CT_B had increased from 608 to 858. The Scrub Error Count (SCRUB_ERR_CT_B) remains at 0. The last time S_TLM_SECTIONS was performed was on 09/22/04, and the SBE_CT_B increased from 286 to 608. IMPACT: None. DOY 04321 (11/16/04) ACE Anomaly G04-0133 - ROBOTT - FOT not receiving ROBOTT pages After being in the pass for 15 minutes (BOT 15:30), no pages had been received from ROBOTT. At least two pages should have been received. Password change occurred on DDS during the pass which may have affected DDS operation. IMPACT: None. After noticing no email messages from the DDS the FOT monitored the pass until such time email messages were received again. DOY 04321 (11/16/04) ACE Anomaly G04-0134 - GDS 34m (DSS-27) Telemetry Outage At 17:09:45, the FOT lost telemetry from DSS-27. At 17:15, the TSS informed the FOT of a communications problem. At 17:26:47, telemetry resumed from DSS-27. IMPACT: Loss of data from 17:09:45 -17:26:47. Data recovered via SSR redumps. DR# N102484 DOY 04321 (11/16/04) ACE Anomaly G04-0135 - No Data Available For System Variable While running the procedure s_tlm_sections.prc, the data server hadn't updated the telemetry parameters before the procedure had reached the telemetry checks. This last occurred on 2/29/04 (AR G04-0017) IMPACT: Can cause problems if the GOTO statement was to the incorrect line. If this problem happens at an IF statement and ROBOTT gives it a GO, then the procedure may execute an inappropriate section of the TSTOL procedure. DOY 04323 (11/18/04) ACE Anomaly S04-0016 - STAR_BKGD_HIGH Configuration Monitor Violation At 19:03:29, STAR_BKGD_HIGH configmon violated. This occurred only once during the pass. IMPACT: On Day 07027 there was a STAR_BKGD_HIGH RH limit violation, however, this problem isn't similar (Ref. AR#SO4-0002). It is believed that this anomaly is an erroneous value due to a processing problem. AR#S04-0017 explains this in greater detail as this has occurred with the STAR_L_TEMP configmon. DOY 04323 (11/18/04) ACE Anomaly S04-0017 - STAR_LTEMP Erroneous Values Over the life of the mission the nominal value of the star_ltemp (star lens temperature) has been between 10-17 degrees. Occasionally the value drops instantaneously to around -14 to -4 degrees. The FOT investigated why this drop of about 20 degrees occurs. After analysis, the FOT determined the negative temperatures occur when the spin rate of the spacecraft is between 4.942 and 4.983 rpm. This trend has happened for the entire mission. The last time this occurred was the last week in August 2004. IMPACT: Unknown at this time. The FOT will continue analysis and monitoring of this event. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Glen A. Miller ACE Flight Operations Observatory Engineer Honeywell Technology Solutions Inc. Goddard Space Flight Center Building 14, Room W10A Mail Stop 428.2 Greenbelt, MD 20771 Office: 301-286-7071 Pager: 800-425-3174 Fax: 301-286-1729 gamiller@pop500.gsfc.nasa.gov ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~