ACE Weekly 10/12/2007 - 10/16/2007 All ACE spacecraft subsystems are performing nominally. Note: ACE Weekly Reports will now cover Wednesday to Tuesday (instead of the previous Friday to Thursday). ============================================================================ Orbit/Attitude: No maneuvers were performed. The next attitude maneuver is scheduled for Monday, 10/29/2007. ============================================================================ OCRs: None ============================================================================ Activities: Space Link Extension (SLE) Testing status DSN continues to troubleshoot 26m SLE problems. The following tests have been scheduled for testing both DSN and the ACE MOC SLE upgrade (v3.1) Day Date DOY Station Wed 10/17 290 DSS-54 Thu 10/18 291 DSS-34 Mon 10/22 295 DSS-66 Wed 10/24 297 DSS-46 Thu 10/25 298 DSS-34 Mon 10/29 302 DSS-46 Thu 11/01 305 DSS-66 with DSS-27 Thu 11/01 305 DSS-27 Mon 11/05 309 DSS-24 Multi-Mission Ops Center (MMOC) The ACE team has started working with the ITOS developers to replace the TPOCC mission software with ITOS. ============================================================================ Anomalies: DOY 286 10/13/2007 S-ACE-0234 G07-0087 DSS-66 S-Band Exciter Problems with DSS-66 S-Band Exciter (uplink) affected CMD, RNG and TLM. The downlink is affected since in the spacecraft is in coherent mode (Downlink frequency based on uplink. Ratio of frequencies = Uplink/Downlink = 240/221). When problems like this have occurred in the past, the FOT has requested that the ground station increase the RF loop bandwidth to improve downlink data capture. However, this was a un-staffed weekend shift. DR#M104463 IMPACT: Several command failures due to bit-flips in the command sequence. All command failures were rejected by the spacecraft. Daily commanding sequence was not completed. The final spacecraft configuration was not nominal but had no impact. 340 seconds of playback data lost, intermittent between DOY 285 2222z to DOY 286 1246z. Note: 340 seconds corresponds to 0.39% daily loss which is reported for data capture metrics. In terms of complete major frames (128 second cycle), the daily data loss corresponds to 9.5%. DOY 286 10/13/2007 S-ACE-0235 G07-0088 ROBOTT/C&C Froze ROBOTT automation software froze during the intermittent telemetry and command failures. IMPACT: The ROBOTT software did not notify the FOT that the daily commanding sequence was not completed and that the final spacecraft configuration was not nominal. DOY 287 10/14/2007 S-ACE-0236 G07-0089 DSS-27 Antenna Stop Ground antenna went to brake causing loss of telemetry and two way lock with spacecraft at 18 minutes before End Of Track. Uplink re-established at 2.5 minutes before End Of Track. SSR playback properly terminated before End Of Track. DR#G108100 IMPACT: If the uplink was not re-established, the SSR playback would have been continuing as the spacecraft changed data rates. This causes the SSR to be stuck in playback mode. Although this has happened in the past and contingencies are in place to automatically reconfigure the SSR at the beginning of the next support, it is preferable to terminate the SSR playback properly before End Of Track.