ACE Weekly 10/29/2008 - 11/04/2008 All ACE spacecraft subsystems are performing nominally. ============================================================================ Orbit/Attitude: Type Attitude Date 10/31/2008 DOY 305 2008 Thrusters 2R 4R+ 4R- Duration 12:43 min Start 16:08:04z Stop 16:20:47z HGAStart -6.75deg HGAStop 7.46deg SunStart 15.76deg SunStop 6.08deg Nutation 0.32deg Firing 64 pulses FuelUsed 0.2107lbs FuelRemain 146.9396lbs FinalSCMass 1381.200lbs The next attitude maneuver is scheduled for Friday 11/14/2008. =========================================================================== OCRs: None ============================================================================ Activities: Data Capture: 100% DOY 300-307 2008 There is a higher than normal risk of data loss from October 2008 through February 2009. If there are problems with the passes, it may not be possible to acquire additional DSN time. This higher-risk period has been occurring every winter for the past couple of years. For more information refer to 10/14/2008 weekly. ============================================================================ Anomalies: DOY 304 10/30/2008 S-ACE-0369 G08-0104 DSS-46 TCP Configuration The station operator did not correctly configure the TCP to send high-rate data to the ACE MOC (low latency). The FOT contacted the station and requested that the low latency channel be switched to high-rate data. DR#C106604. This same problem occurred on 10/15/2008 (AR#G08-0096 DR#C106579). DSN is reviewing the desktop/TCP configuration. IMPACT: Manual intervention required. Activities delayed 23 minutes. DOY 305 10/31/2008 S-ACE-0370 G08-0105 AC2WS1 Hard Drive Failure AC2WS1 root drive failed. SysAdmins notified. IMPACT: Minimal. String 2 can still function as a backup for operations. DOY 305 10/31/2008 S-ACE-0371 G08-0106 Unable to Log In AC2PC1 AC2PC1 is used for maneuver planning. While attempting to log in, the incorrect password was entered. After successfully entering the password, a dialog box appeared "The System Log is full". No accounts were able to log into the computer. After 20 minutes, the FOT was able to log into the computer and plan the maneuver. The problem could not be reproduced for the SysAdmins. IMPACT: A second computer (ACETLANPC) was available for maneuver planning if AC2PC1 was completely unavailable. DOY 308 11/03/2008 S-ACE-0372 G08-0107 DSS-46 SLE CMD Problems The ACE MOC was able to successfully BIND to DSS-46 and send commands, but the commands were never radiated. After several different troubleshooting actions, the station unloaded and reloaded desktop. Commands were then successful. DR#C106610 IMPACT: Activities delayed 25 minutes. DOY 308 11/03/2008 S-ACE-0373 G08-0108 DSS-46 TLM Problems The station's TCP was having difficulty processing telemetry frames for unknown reasons. Errors were being found in the Convolutional and Reed-Solomon Decoders resulting in ~0.1% data loss over 40 minutes. The FOT requested that the station increase the RF Loop Bandwidth on the receivers and this resolved the problem. DR#C106611 IMPACT: All data was captured through redumps. Although 0.1% data loss is per frame, this corresponds to a 10% loss of complete major frames (42 minutes). DOY 309 11/04/2008 S-ACE-0374 G08-0109 SSR Not Idled The automation software is designed to Idle the SSR 15 minutes before End Of Track and perform redumps with the time remaining. However, the automation software failed to execute this procedure. The SSR was still in playback when the spacecraft transitioned to low-rate. When this occurs, the SSR remains stuck in playback mode (01/12/2005 AR#S05-0002 and 12/01/2005 AR#G05-0148). IMPACT: The procedure S_OPS_REC_PLBK handles this contingency by idling the SSR at the beginning of the next support and redumping any missing data. DOY 309 11/04/2008 S-ACE-0375 G08-0110 Postpass Dumplist Not Correct The postpass calculation of redumps used the wrong TPOCC history file to determine the end of the SSR segment. Manual review of the pass uncovered the problem and the dumplist was corrected. The problem appeared because 2 passes were scheduled for 1 day. MOCR#1379 has been opened to correct the offline tool. IMPACT: 38 minutes of data would have been lost if the problem had not been caught.