ACE Weekly 07/29/2015 - 08/04/2015 All ACE spacecraft subsystems are performing as expected. ======================================================================== Attitude/Orbit: Type Attitude Date 08/04/2015 DOY 216 2015 Thrusters 2R 4R+ 4R- Duration 16:03 minutes Start 14:30:19z Stop 14:46:22z ra,decStart 117.66,26.24 ra,decStop 121.72,11.79 ra,decExpect 121.95,11.22 Deviation 0.61 deg (-3.9%) HGAStart -8.79 deg HGAStop -8.34 deg SunStart 17.76 deg SunStop 13.32 deg SpinStart 5.0096 rpm SpinStop 5.0139 rpm Nutation 0.19 deg Firing 81 pulses FuelUsed 0.2409 lbm FuelRemain 96.7656 lbm FinalSCMass 1331.025 lbm Note: The previous week attitude maneuver (DOY 209) incorporated planning for the upcoming (quarterly) crossing of the ecliptic, and targeted an initial HGA angle of 4 degrees (reaching ~11 degrees by DOY 216). This plan provided the maximum average sun angle for the week while nearing the ecliptic crossing - fortunately, also rendering the usage of WS1 for the ground anomaly recovery on DOY 210 feasible (see below under the Anomalies section). - The next attitude maneuver is scheduled for Tuesday, 08/11/2015 ======================================================================== OCRs: None ======================================================================== Activities: Data Capture: 100% DOY 207-214 2015 MMOC: Quarterly (3Q) security scans performed on the MMOC operational systems on 07/30/2015. Operational System Failover: The FOT performed a switch to the primary operational system (mmocops1p) on 07/30/15. Both ASC and WS were informed of the IP address change. ======================================================================== Anomalies: - DOY 210 07/29/2015 S-ACE-33: Procedure Stuck Waiting for Command Verification At 2015/210/11:41:32z, shortly after the beginning of the 11:35z-14:55z DSS-65 pass, the ground system experienced an anomaly that halted the ace_pass procedure just after starting recording on SSR-B. This event led to no playback of SSR-A data and both recorders continued to record from that point onwards. To resolve the issue, the FOT added a WS1 pass at BOT 2015/210/20:20:00z. The FOT planned to manually set SSR-B from recording to idle before normal SSR activities and continue the pass as normal. Effectively, this would yield the same result as if the DSS-65 pass was lost. Based on the evaluation of the ground system observables, the ITOS command graph component is suspect, but the confirmed root cause of the anomaly is still under investigation. IMPACT: WS1 contact scheduled. Additionally, the 3Q security scans were delayed one day due to addition of the WS1 support. - DOY 210 07/29/2015 (SOAR IDs TBD): WS1 Loss of TLM Capability A WS1 pass was added on 2015-210 (BOT:20:20:00z) to workaround the MMOC ground anomaly experienced during the previous DSS-65 contact, which caused both SSR-A and SSR-B to remain on RECORD state. Following initial (successful) commanding and telemetry capabilities, at approximately ~20:35:12z, the MMOC stopped receiving ACE telemetry. Automation paused (as expected) waiting for verification of RECORD_S0 command, and the command was retransmitted every 60 seconds. A series of re-sweeps were performed (one from WS1, another via Wallops) in conjunction with a re-start of the ace_pass procedure with no success (i.e., poor signal to noise per bit achieved). WS Systems Engineering then performed a reset of the WS1 receiver(s), which allowed the station to lock up successfully on the signal. The FOT re-established telemetry around 21:59:44z and proceeded to configure SSR-B from record to idle and started the playback of SSR-A. The SSR-A dump was shortened from 201 to 43 slices and the remaining 158 slices (approx. 40 minutes) were carried-over to the next pass on DOY 211. The FOT will follow-up with WS personnel to obtain more information regarding the root cause of the anomaly. IMPACT: The FOT worked with WS and WAPS operations/engineering personnel to troubleshoot the problem (re-starting the MMOC pass procedure) and re-establish telemetry following the receiver reset. Lastly, the FOT confirmed post-pass that there were no (VC4) DOY 210 data losses.