ACE Weekly 10/31/2012 - 11/06/2012 All ACE spacecraft subsystems are performing as expected. ======================================================================== Orbit/Attitude: Type Attitude Date 11/06/2012 DOY 311 2012 Thrusters 2R 4R+ 4R- Duration 11:41 min Start 20:45:17z Stop 20:56:58z HGAStart -7.50deg HGAStop +8.78deg SunStart 6.77deg SunStop 10.75deg SpinStart 5.0780rpm SpinStop 5.0809rpm Nutation 0.14deg Firing 60 pulses FuelUsed 0.1868lbs FuelRemain 118.5548lbs FinalSCMass 1352.815lbs The next attitude maneuver is scheduled for Tuesday 11/13/2012. Please refer to the new section at the end for the sun angles since starting weekly attitude maneuvers in reference to the SWEPAM instrument. ======================================================================== OCRs: None ======================================================================== Activities: Data Capture: 100% DOY 302-309 2012 A third WS1 certification test was attempted on Friday 11/2/2012. This test was to be performed on the current operational system; previous tests were done with the current backup system. However, the WS1 firewalls hadn't been updated to allow a connection to the operational MMOC computer. The WS1 firewall will be updated in 2 weeks. This restarts the count for 3 consecutive successful certification tests. The next certification test is scheduled for 11/20/2012, which coincides with a day we are unable to get a DSN pass. ======================================================================== Anomalies: DOY 308 11/03/2012 S-ACE-0654 G12-0015 MMOC in test mode The ACE context on the operational system was configured for a WS1 test on Friday 11/02/2012. The ACE context was not reconfigured back for operations. The Saturday 11/03/2012 pass started with "add_prompts" enabled and a redump of data scheduled. IMPACT: Manual intervention required on Saturday, activities were delayed 20 minutes while "add_prompts" was disabled and the redump of old data was terminated. There was no data loss. ======================================================================== Average Sun Angles With Weekly Attitude Maneuvers The following table will be updated each week to provide a history of the spacecraft sun angle. The project has accepted the SWEPAM team proposal to keep the spacecraft at larger sun angles with weekly attitude maneuvers. The SWEPAM-Ion instrument has a series of channel electron multipliers (CEMs) and larger sun angles allows more responsive CEMs to measure the solar wind. Dates Avg SEV Avg Sun Comments ----------- ------- ------- -------------------------------------- 10/18-10/23 5.1deg 11.0deg 10/23-10/28 3.3deg 9.3deg 10/28-11/06 2.0deg 7.3deg sun-sev=5.3 due to 9days between mnvrs Notes: * SEV = Sun-Earth-Vehicle angle. * When the spacecraft antenna is pointed directly towards earth, the spacecraft's sun angle will be equal to the Sun-Earth-Vehicle angle. * The SEV angle is determined by the size of the orbit around L1. * With the spacecraft antenna performance and weekly maneuvers, the sun angle will be ~6deg more than the SEV angle. * This results in the spacecraft antenna aspect angle being kept between 5 and 9 degrees and never pointing directly back at earth. * For reference, the SWEPAM team prefers sun angles above 13 degrees. * With the current size of the L1 orbit, the sun angle will be above 13 degrees for 45% of the time.