ACE Weekly 07/16/2014 - 07/22/2014 All ACE spacecraft subsystems are performing as expected. ======================================================================== Orbit/Attitude: Type Attitude Date 07/21/2014 DOY 202 2014 Thrusters 2R 4R+ 4R- Duration 10:54 min Start 14:30:31z Stop 14:41:25z ra,decStart 118.67,35.16 ra,decStop 112.43,27.58 ra,decExpect 111.98,26.45 Deviation 1.32 deg HGAStart +11.01 deg HGAStop -4.61 deg SunStart 14.85 deg SunStop 10.43 deg SpinStart 4.9893 rpm SpinStop 4.9914 rpm Nutation 0.20 deg Firing 55 pulses FuelUsed 0.1715 lbm FuelRemain 105.4896 lbm FinalSCMass 1339.750 lbm The next attitude maneuver is scheduled for 07/29/2014. ACE will cross the ecliptic plane next month (~8/7/2014). For the next 3 weeks (7/21, 7/28, 8/4), each maneuver will turn the spacecraft antenna closer to Earth, resulting in a better downlink signal strength. Between each maneuver, the spacecraft will "drift" away from earth to an 11 degree antenna angle with the reduced downlink signal strength. This continues to maximize the spacecraft sun angle (OCR ACE-285 CDS-051 10/18/2012) as the spacecraft is turned from pointing above the ecliptic plane to below the ecliptic plane. This week's attitude maneuver was off by 1.32 degrees (~ -11% short). The investigation into the maneuvers not reaching the target continues. The "drift" buffer has been increased an additional day to allow for the intermittent short maneuvers. Date Actual ra,dec Expected ra,dec deviation short (%) 04/01/2014 18.95 -5.15 19.18 -5.06 0.25 deg -3% 04/08/2014 27.53 -0.69 27.76 -0.74 0.24 -2% 04/15/2014 36.18 2.70 36.37 2.52 0.26 -1% 04/22/2014 44.93 5.96 45.12 5.83 0.23 -1% 04/29/2014 54.60 12.03 54.87 11.87 0.31 -1% 05/06/2014 60.45 26.36 60.85 27.05 0.78 -5% 05/13/2014 63.39 32.25 63.78 33.05 0.86 -12% 05/20/2014 69.49 35.51 70.20 35.72 0.61 -9% 05/27/2014 76.45 37.45 76.99 37.51 0.43 -7% 06/03/2014 82.17 39.11 82.40 39.11 0.18 -3% 06/10/2014 91.99 38.97 91.84 39.06 0.15 +2% 06/17/2014 95.60 39.71 95.96 39.70 0.28 -8% 06/24/2014 101.96 39.24 102.16 39.13 0.19 -3% 07/01/2014 108.48 38.10 108.74 37.98 0.24 -4% 07/08/2014 114.35 36.62 114.77 36.37 0.42 -7% 07/15/2014 118.89 35.15 119.48 34.81 0.59 -12% 07/21/2014 112.43 27.58 111.98 26.45 1.32 -11% ======================================================================== OCRs: None ======================================================================== Activities: Data Capture: 100% DOY 187-194 2014 ======================================================================== Anomalies: None