ACE Weekly 01/21/2009 - 01/27/2009 All ACE spacecraft subsystems are performing nominally. ============================================================================ Orbit/Attitude: Type Attitude Date 01/21/2009 DOY 021 2009 Thrusters 2R 4R+ 4R- Duration 13:56 min Start 17:59:31z Stop 18:13:27z HGAStart -6.88deg HGAStop 7.49deg SunStart 5.70deg SunStop 16.54deg SpinStart 5.0016rpm SpinStop 5.0052rpm Nutation 0.08deg Firing 70 pulses FuelUsed 0.2283lbs FuelRemain 145.0476lbs FinalSCMass 1379.308lbs The next attitude maneuver is scheduled for Monday 02/02/2009. =========================================================================== OCRs: None ============================================================================ Activities: DOY 026 01/26/2009 - DSS-24 Return To Service Demo DSS-24 is returning to service after Ka-Band Phase 2 upgrade (11/03/2008-02/01/2009). The station had trouble acquiring the low-rate data during the last 10 minutes of the support. The station eventually did acquire low-rate data after the end of track. The station will investigate the glitch. In spite of the glitch, the Demo was deemed successful. DSS-34 had already undergone a Ka-Band Phase 2 upgrade (the ACE Return To Service Demo was 09/24/2008). Data Capture: 100% DOY 021-027 2009 The risk of data loss has returned to normal. The viewperiod from northern hemisphere antennas has been increasing since mid-December and is now 9 hours each day. Five of the 7 DSN antennas that ACE uses are in the northern hemisphere. Also, the overlap between Mars missions has decreased. Mars has moved ~1 hour ahead of the sun and the current position of ACE gives ~4 hours of viewperiod that is outside of the Mars viewperiod. There was no data loss from October 2008 through January 2009. Although there were several passes delayed by ~30 minutes due to problems, there were no passes that were completely lost. This along with a heightened awareness of the limited DSN resources during station daylight hours, resulted in no data loss. A test of the Multi-Mission Ops Center will be performed Thursday 01/29/2009 1545-1745z. The ACE and WIND spacecrafts will be commanded with the new mission software currently under development (ITOS). ============================================================================ Anomalies: DOY 020 01/20/2009 S-ACE-0410 G09-0007 DSN Tracking Data To FDF FDF did not receive tracking data from 01/16/2009 through 01/21/2009. This is the same problem as anomaly# G08-0122 that occurred last November (11/19/2008-11/30/2008). DSN was notified of the problem on 01/20/2009. JPL had switched tracking data stots that were incorrectly configured. IMPACT: JPL will retransmit the lost tracking data to FDF if necessary. FDF was still able to perform ACE orbit determination (OD) on 01/20/2009. The problem was resolved before the next scheduled ACE OD on 01/30/2009. DOY 021 01/21/2009 S-ACE-0411 G09-0008 DSS-27 Antenna Stop The ground antenna stopped in the middle of a support (1607-1626z). The ground station performed a remote reset. DR#G109188 IMPACT: 20 minute telemetry outage was redumped at the end of the support. DOY 022 01/22/2009 S-ACE-0412 G09-0009 DSS-46 CMD/SLE Problems DSS-46 was unable to process SLE commands at Beginning Of Track (BOT). The problem was resolved when the station unloaded and reloaded the desktop. DR#C106790 IMPACT: Activities delayed 15 minutes. DOY 026 01/26/2009 S-ACE-0413 S09-0001 S3DPU_I limit violation S3DPU current (S3DPU_I) briefly violated the red high limit (RH > 145mA). The S3DPU Idle Counter (SSDIDLECTR) was at 72. 2009-026-18:54:48 - 18:54:50 149.744-150.528mA IMPACT: The last brief S3DPU_I violation was 2008-345:23:33:35. S3DPU_I is higher when the instruments are processing more data as indicated by a low SSDIDLECTR.