ACE Weekly 07/10/2013 - 07/16/2013 All ACE spacecraft subsystems are performing as expected. ======================================================================== Orbit/Attitude: Type Attitude Date 07/15/2013 DOY 196 2013 Thrusters 2R 4R+ 4R- Duration 4:59 min Start 16:44:33z Stop 16:49:32z HGAStart -8.83 deg HGAStop +8.92 deg SunStart 12.71 deg SunStop 13.06 deg SpinStart 4.9438 rpm SpinStop 4.9448 rpm Nutation 0.07 deg Firing 25 pulses FuelUsed 0.0854 lbm FuelRemain 113.1272 lbm FinalSCMass 1347.387 lbm The DSN Goldstone site was down for a "G86 power cutover" on Tuesday 07/16/2013. No Goldstone antennas were available during the day and this week's maneuver was scheduled for Monday. The next attitude maneuver is scheduled for Tuesday 07/23/2013. ======================================================================== OCRs: DOY 196 (07/15/2013) 1729-1731z SWICS-037 Change event prioritization The SWICS instrument team changed the event prioritization for telemetry. This, along with the 2 previous OCRs (SWICS-035 5/31/2012 & SWICS-036 8/21/2012), are in response to the time-of-flight trigger anomaly that started 08/23/2011 which resulted in an increased background. In particular, this week's commanding set the protons and alphas to the bulk of old nominal region. ======================================================================== Activities: Data Capture: 100% DOY 188-195 2013 The analysis of the second Santiago ranging/uplink test (7/9/2013) has been completed. Santiago will provide southern hemisphere ranging for the DSCOVR mission. ACE operations may also be interested in using Santiago depending on availability. There were several problems and additional tests will be scheduled as Near Earth Network team works these issues. None of these issues affect current ACE operations, but are included here as information. * Santiago downlink freq was set to 2278.00 instead of 2278.368 MHz. * The 10 second round-trip light time is 10,000,000,000 nanoseconds, which can't be stored by a 4 byte integer (4,294,967,296). The range can be corrected by adding 8,589,934,592 (2 "overflows") * After the correcting for the 2 overflows, the Santiago range was still incorrect. (1,288,948 km versus the expected 1,598,534 km) * Doppler needs to be compensated with the 240/221 dnlk/uplk ratio. * Doppler problems also occurred due to the wrong dnlk frequency. * Doppler at the minute mark is flagged as invalid. * Santiago had troubles locking onto the downlink carrier. * Also, ACE was farther away for the 7/9/2013 test 4/15/2013 ~1,419,641 km 7/9/2013 ~1,598,534 km (ACE max range ~1,600,500km) The next Santiago ranging test is scheduled for Thursday 7/18/2013. DOY 186 07/05/2013 1400-1700z DSS-24 ACE Return To Service Demo Note, this should have been included in last week's report. No problems were found with the RTS Demo with DSN's DSS-24. DSS-24 (34m antenna in Goldstone, CA) has been down since 4/29/2013 for "AZ Track Replacement", "Depot Level Maintenance" and "Gain Select Installation". DSS-24 started taking passes on 7/13/2013. Note, there are 6 DSN stations available for ACE, 80% of the ACE passes are with DSS-27 and <10% are with DSS-24. NOAA SWPC has several antennas for tracking ACE for real-time solar wind data. The NICT antenna in Tokyo will be unavailable from October 2013 to March 2014. The KSWA antenna on Jeju Island will be able to cover the time. During typhoons, however, AFSCN time will be requested. Note, NOAA activities are separate from the Goddard Flight Operations, but noteworthy topics are occasionally included in this report. ======================================================================== Anomalies: None