ACE Weekly 12/03/04 - 12/09/04 All ACE spacecraft subsystems are performing nominally. ============================================================================ Orbit/Attitude: Maneuvers completed Type Attitude Station Keeping Date 12/06/04 12/06/04 DOY 341 2004 341 2004 Thrusters 2R 4R+ 4R- 3A 4A Duration 14:58 minutes 00:58 minutes Start Time 16:37:28z 18:38:48z Stop Time 16:52:26z 18:39:45z Firing 76 pulses continuous The next attitude maneuver is scheduled for 12/20/04. The ACE Solar Exclusion Zone transit (SEV angle < 4.75�) ends on 12/09/04. The minimum SEV angle for this transit was 0.83� (solar disc radius~0.26�). DSN 34m stations and DSS-27 have had no problems acquiring downlink for angles greater than 0.50�. DSN 26m stations are not used for angles less than 1.0�. The next transit will be from 02/10/05 to 03/04/05 with a minimum SEV angle of 1.44� on 02/21/05. All subsequent SEV angles will be greater than 1.0� and no further problems are expected until 2009 when the SEZ transits begin again. ============================================================================ OCRs Executed: None ============================================================================ Ongoing Activities: ROBOTT ACE transitioned to Lights Out Operations on 11/13/04. All nominal realtime operations are now being performed using ROBOTT, with the exceptions of maneuvers and special commanding. 20 DRs have been written for ROBOTT v0.9. The ROBOTT developers have uncovered and are fixing a year rollover problem. Since Week 1 starts on the first week with 4 days in the new year, it is possible to have Jan 1, 2 and 3 in the previous year's final week (52 or 53). The software currently deletes the previous year's schedule on Jan 2. A temporary patch is being developed and will be implemented before the end of the year. ============================================================================ Extra Spacecraft Activities: We have received a request from Jim Griffee (SWEPAM) to investigate the possibility of commanding the SWEPAM-Ion instrument to collect certain data. The goal is to characterize the instrument's spectral sensitivity to CEM voltage steps, but doing so in the presence of an ever varying "calibration" signal...the real-time solar wind. A telecon was held on 12/07/04, 12/07/04, to further discuss the data collection requirements and the feasibility of commanding the instrument to capture that data. ============================================================================ Anomalies: DOY 338 (12/03/04) ACE Anomaly G04-0149 GDS 26m (DSS-16) CMD MOD Index Incorrect CMD MOD Index delayed beginning of activities by 30 minutes. IMPACT: None. Playback completed with 9 minutes to spare. DR#G105031 DOY 340 (12/05/04) ACE Anomaly S04-0020 SWICS Limit Violations SSCGRP28V2, SSCGR20V, SSCPAP5V and SSCPAM5V had brief red and yellow limit violations between 07:03:49 and 07:40:14 during elevated solar activity. Jim Raines Notified. IMPACT: Unknown DOY 340 (12/05/04) ACE Anomaly G04-0150 GDS 26m (DSS-16) CMD MOD Index Incorrect CMD MOD Index delayed beginning of activities by 40 minutes. Problem resolved during off-shift by FOT contacting DSN from home. IMPACT: None. Playback completed with 1 minute to spare. DR#G105037 DOY 340 (12/05/04) ACE Anomaly G04-0151 Error in ROBOTT Notification ROBOTT C&C notification for 'proc stalled' incorrectly states which proc is stalled. IMPACT: Increased effort to isolate and resolve anomaly. CDSID#21118 DOY 343 (12/08/04) ACE Anomaly G04-0152 Premature Procedure Start ROBOTT/C&C did not complete results checking for the procedure uleis_motor_error before starting the procedure s_ops_plbk_complete. Two minutes after starting s_ops_plbk_complete, results checking for uleis_motor_error timed out and C&C killed all active procedures. IMPACT: Minimal. Proc s_ops_plbk_complete was near completion when terminated. CDSID#21122 DOY 343 (12/08/04) ACE Anomaly G04-0153 ROBOTT Continuous Loop After the premature termination of s_ops_plbk_complete, C&C started issuing the 'proc failed' message. C&C did not start the proc 'g_end_day'. After C&C was resumed after EOT, C&C went into a continuous loop of (killp all, /pause, /clear). C&C was terminated and the proc 'g_acedown' was not executed. IMPACT: Final spacecraft state-of-health check was not completed. CDSID#21123 DOY 343 (12/08/04) ACE Anomaly G04-0154 CMD Count Incorrectly Calculated FOT pass summary tool incorrectly calculated the day's CMD Count since the downlink format was Science at EOT (Science has the cmd counts in different minor frames.) IMPACT: File manually updated. MOCR 04-1112