ACE Weekly 09/21/2016 - 10/04/2016 All ACE spacecraft subsystems are performing as expected. ======================================================================== Attitude/Orbit: Type Attitude Spin Down Date 09/22/2016 09/22/2016 DOY 266 2016 266 2016 Thrusters 2R 4R+ 4R- 3R- 4R- Duration 12:14 minutes 14 seconds (~13.70s) Start 15:45:25z 17:12:20z Stop 15:57:39z 17:12:34z ra,decStart 175.72,-11.13 186.67,-13.64 ra,decStop 186.67,-13.64 186.68,-13.66 ra,decExpect 186.70,-13.98 186.67,-13.64 Deviation 0.10 deg (-0.9%) HGAStart -8.44 deg +6.74 deg HGAStop +6.74 deg +6.71 deg SunStart 11.98 deg 15.34 deg SunStop 15.34 deg 15.32 deg SpinStart 5.0904 rpm 5.0939 rpm SpinStop 5.0939 rpm 4.9500 rpm Nutation 0.17 deg 0.27 deg Firing 63 pulses Continuous FuelUsed 0.1798 lbm 0.0422 lbm FuelRemain 88.088 lbm 88.046 lbm FinalSCMass 1322.347 lbm 1322.305 lbm Type Attitude Attitude Date 09/27/2016 10/03/2016 DOY 271 2016 277 2016 Thrusters 2R 4R+ 4R- 2R 4R+ 4R- Duration 10:33 minutes 9:53 minutes Start 16:02:44z 17:55:29z Stop 16:13:17z 18:05:22z ra,decStart 186.83,-13.61 197.48,-10.52 ra,decStop 197.38,-10.66 203.39,-17.43 ra,decExpect 198.53,-10.91 203.41,-17.68 Deviation 1.10 deg (-9.3%) 0.20 deg (-2.2%) HGAStart -4.75 deg -1.43 deg HGAStop +7.88 deg +8.75 deg SunStart 12.04 deg 9.92 deg SunStop 15.69 deg 18.76 deg SpinStart 4.9499 rpm 4.9528 rpm SpinStop 4.9530 rpm 4.9553 rpm Nutation 0.16 deg 0.14 deg Firing 53 pulses 49 pulses FuelUsed 0.1710 lbm 0.1469 lbm FuelRemain 87.875 lbm 87.728 lbm FinalSCMass 1322.135 lbm 1321.988 lbm The 9/22/2016 maneuvers had been moved from 9/20/2016 due to a DSN antenna anomaly, which caused ACE to lose its 9/20/2016 support (reference 09/14/2016 - 09/20/2016 ACE weekly). The 9/22/2016 spin down maneuver targeted 4.95 rpm. Flight Dynamics' post-maneuver report estimated the maneuver had a performance error of 0%. ACE had last performed a Spin Down maneuver on 5/14/2013. The weekly Attitude Maneuver was executed on 9/27/2016. Post-maneuver analysis estimated the attitude maneuver underperformed by ~9.3%. Preliminary investigation found the maneuver had been planned using a spin rate of 4.5 rpm, instead of 4.95 rpm (reference SOAR S-ACE-99). Root Cause and Corrective Analysis (RCCA) will be performed. Upcoming Maneuver Schedule: - Attitude Maneuver: Tuesday, 10/11/2016 - Station Keeping (SK-82): TBD ======================================================================== OCRs: None ======================================================================== Activities: Data Capture: 100% 2016 DOY 263 - 2016 DOY 276 ======================================================================== Anomalies: DOY 271 09/27/2016 SOAR S-ACE-99 Maneuver underperformed due to incorrect spin rate Weekly attitude maneuver performed on 9/27/2016. Post-maneuver analysis estimated the maneuver underperformed by ~9.3%. Preliminary FOT investigation found the maneuver was planned using a spin rate of 4.5 rpm, instead of 4.95 rpm. IMPACT: Immediate - FOT confirmed post-maneuver attitude within constraints and would last until our next regularly scheduled maneuver day, 10/03/2016. No immediate corrective action was necessary to address the underperformance. NASA MD notified. Preventive - Root Cause and Corrective Analysis (RCCA) performed. Automated Validation of GMAN User Inputs will be implemented (e.g. spin rate 4.9-5.1 rpm, delta between current and target attitudes, date verification and fuel mass change).