ACE Weekly 02/06/2013 - 02/12/2013 All ACE spacecraft subsystems are performing as expected. ======================================================================== Orbit/Attitude: Type Attitude Date 02/12/2013 DOY 043 2013 Thrusters 2R 4R+ 4R- Duration 21:04 min Start 15:59:07z Stop 16:20:11z HGAStart -8.72deg HGAStop +9.03deg SunStart 9.87deg SunStop 10.39deg SpinStart 5.0754rpm SpinStop 5.0810rpm Nutation 0.07deg Firing 107 pulses FuelUsed 0.3162lbm FuelRemain 116.2324lbm FinalSCMass 1350.493lbm The next attitude maneuver is scheduled for Tuesday 02/19/2013. ======================================================================== OCRs: None ======================================================================== Activities: Data Capture: 100% DOY 034-041 2013 NOAA Space Weather Prediction Center is always looking for antenna partners. They are currently working with APL's 18-meter antenna to track Stereo Beacon data, http://www.swpc.noaa.gov/stereo/. During the discussions, APL noted that they have tracked ACE at both high and low data rates and are capable of commanding to ACE. This is being included in this weekly for informational purposes, as ACE operations are managing pretty well with DSN and NEN's WS1. Plans are underway to test ranging with ACE and the SSC/Santiago 9-meter antenna. The test will be used in planning for the DSCOVR mission and will occur in the next few months. The NASA's Near Earth Network (NEN) has contracts with this and other commercial antennas. NEN will be coordinating the test with ACE operations at GSFC. ======================================================================== Anomalies: DOY 040 02/09/2013 S-ACE-0647 G12-0009 DSN TLM SLE Provider The MMOC SLE Software (MUS) was unable to connect to DSN TLM SLE Provider (ECONNREFUSED). The FOT requested that JPL restart their SLE process which fixed the problem. This problem last occurred on 9/15/2012. DR#N108628 IMPACT: Activities delayed 45 minutes. No impact to NOAA SWPC since the spacecraft was in RTSW during this time. ======================================================================== Average Sun Angles With Weekly Attitude Maneuvers Dates Avg Sun Avg SEV Sun-SEV (indicates extra s/c tilt) ----------- ------- ------- ---------------------------------- 10/18-10/23 11.0deg 5.1deg 5.9deg 10/23-10/28 9.3deg 3.3deg 6.0deg 10/28-11/06 7.3deg 2.0deg 5.3deg 11/06-11/13 8.4deg 3.8deg 4.6deg 11/13-11/20 10.3deg 6.3deg 4.0deg 11/20-11/27 12.7deg 8.6deg 4.1deg 11/27-12/04 14.9deg 10.1deg 4.8deg 12/04-12/11 16.0deg 10.9deg 5.1deg 12/11-12/18 16.8deg 11.3deg 5.5deg 12/18-12/27 16.5deg 10.7deg 5.8deg 12/27-01/03 16.0deg 9.1deg 6.9deg 01/03-01/08 15.2deg 7.2deg 8.0deg 01/08-01/15 13.8deg 6.0deg 7.8deg 01/15-01/22 12.3deg 4.0deg 8.3deg 01/22-01/29 10.6deg 2.4deg 8.2deg 01/29-02/05 9.1deg 3.2deg 5.9deg 02/05-02/12 8.4deg 5.1deg 3.3deg The following is background information that will be included in each weekly report. 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. The maximum sun angle follows the Sun-Earth-Vehicle angle (SEV). The SEV angle is determined by the size/shape of the orbit around L1. When the spacecraft antenna is pointed directly towards earth, the spacecraft's sun angle will be equal to the Sun-Earth-Vehicle angle. With weekly maneuvers, the average sun angle can be kept 4-8deg 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.