STEREO Weekly Meeting Minutes for 2014-07-15 (Week 29) ANNOUNCEMENTS ------------- * There will be a commercial power outage at the MOC on Saturday, July 26. This is not expected to affect operations. * New call-in information for the weekly telecons was presented. This information will be distributed separately. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 28 (Jul 7-13) * On day 193 (Jul 12), during the DSS-55 support for Ahead, the receiver and ranging processor dropped out between 1109z and 1111z. This anomaly resulted in the loss of 811 frames of SSR data. See DR #M108145 for more information. * On day 194 (Jul 13), during the DSS-63 support for Ahead, DSS-63 declared the receiver orange due to an the inability of the cryogenic system to maintain the SNT (System Noise Temperature). This anomaly degraded the downlink signal by 10 dB, resulting in the loss of real-time telemetry and ranging data for the duration of the 4.5 hour support. SSR pointers were repositioned on the following support. See DR #M108149 for more information. * On day 189 (Jul 8), during the DSS-55 support for Behind, turbo decoder lock was lost intermittently at 0956z and again at 1410z. This anomaly resulted in the loss of five frames of SSR data. * On day 190 (Jul 9), during the DSS-45 support for Behind, telemetry lock was lost intermittently beginning at 0226 through 0310z due to heavy rain. This anomaly resulted in the loss of 18,870 frames of SSR data. See DR #C110351 for more information. * On day 188 (Jul 7), IMPACT successfully loaded a flight software patch to LET on Behind to reduce telemetry generation in preparation for HGA side lobe operations. Last week it was reported that the same patch on Ahead was unsuccessful. It has since been determined that it was successful, but the verification telemetry hadn't been received. * The week started with the instruments being turned off on Ahead the previous day for solar conjunction testing. * On day 188 (Jul 7), the 69th momentum dump was executed successfully on Ahead at 0945z, which imparted a delta V of 0.104 m/sec. This momentum dump was performed on the first side lobe. The momentum was adjusted to a lower setting than usual, 8 N-m-s, as will be done during solar conjuction. * On days 188 through 192 (Jul 7-11), HGA side lobe operations, superior solar conjunction operations, including entry and exit, were successfully tested on the Ahead observatory. The actual flight configuration and procedures were used with the exception of the SSR configuration and instrument real-time telemetry for side lobe operations. These will be tested on the Behind spacecraft. The Ahead observatory was returned to operational mode and all instruments resumed science data collection by 192-1505z (Jul 11), with the exception of the high voltage ramp up of the IMPACT SIT instrument, which is scheduled for day 195 (Jul 14). The test validated the solar conjunction observatory configuration to ensure that the spacecraft and instruments remain safe, including the HGA feed, and that the necessary engineering data can be recorded to analyze performance during the actual solar conjunction communications blackout period. This test provided valuable operational results and generated the following four significant issues: 1. IMU will remain on for three days after a star tracker failure to promote to AAD mode anomaly. Systems is investigating. CR-6832 documents. The star tracker did promote successfully after about an hour. When the spacecraft autonomously reset after three days, the star tracker promoted to AAD mode right away, and the IMU was turned off by the reset. An autonomy rule or change in the fault protection rules to turn the IMU off after the star tracker comes back online is being developed, to preserve the remaining lifetime of the IMU. 2. Ranging signal is intermittent on HGA side lobe operations. This was a known issue from previous testing. Subsequent FDF analysis indicated that Doppler data can be used to meet navigation requirements. 3. G&C routine SSR partition will overwrite after two days. The planned SSR reconfiguration to resize the spacecraft partitions for the duration of the second side lobe period, which also includes the instrument science partition reconfiguration, is being developed. 4. Nearly constant fine pointing loss upon recovering G&C and enabling GT usage. G&C is investigating. Information received during the telecon indicated that a G&C configuration parameter had been set incorrectly. The fine pointing is expected to improve. * The average daily SSR playback volume during the week was 2.2 gigabits for Ahead, and 2.8 gigabits for Behind. Week 29 (Jul 14-20) * The HV ramp-up for IMPACT/SIT on Ahead was completed on Monday, Jul 14. * IMU-B on Ahead was turned on for one hour on Monday, Jul 14, in an attempt to solve the problem with the fine pointing control. * A 2 hour Project Interface Test (PIT) will be carried out between the Ahead spacecraft and the new 34 meter station D35 at Canberra on Thursday, Jul 17. There will be no instrument commanding or SSR playback during this pass. This test will be mostly a connectivity test. * Station 63 did not recover from its cryogen problem in time for the Behind track yesterday (Jul 14), resulting in the loss of the track. Pointers were not reset. The station problem was fixed last night, and a successful track with Behind was carried out this morning. * The 29th SECCHI Step Calibration on Behind was carried out this morning (Jul 15). It is expected that the SECCHI data from this calibration was not affected by the previously lost track. * The 20th HGA calibration on Behind was carried out this morning (Jul 15) during the station 63 pass. The results so far appear to be nominal. * Ahead has 13 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Thursday, Jul 17 (D43 at 720 kbps), Friday, Jul 18 (D63), Saturday, Jul 19 (D43 at 720 kbps), and Sunday, Jul 20 (D14 at 720 kbps). The following passes will be carried out at 160 kbps: Tuesday, Jul 15 (D55), Wednesday, Jul 16 (D65), Thursday, Jul 17 (D55), Saturday, Jul 19 (D55 and D15), and Sunday, Jul 20 (D65). ESA Malargue passes are scheduled for Monday and Tuesday, Jul 14-15. * Behind has 10 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Monday, Jul 14 (D63), Tuesday, Jul 15 (D63 at 720 kbps), Friday, Jul 18 (D63 at 720 kbps), and Saturday, Jul 19 (D14). The following passes will be carried out at 160 kbps: Wednesday, Jul 16 (D55), Thursday, Jul 17 (D45 and D54), Friday, Jul 18 (D45), Saturday, Jul 19 (D25) and Sunday, Jul 20 (D55). Week 30 (Jul 21-27) * On Thursday, Jul 24, a 3 hour project interface test (PIT) with the new 34 meter station D35 at Canberra will be carried out with Behind. There will be no instrument commanding or SSR playback during this pass. * On Sunday, Jul 27, a return-to-service pass with station 26 will be carried out. There will be no instrument commanding or SSR playback during this pass. * Ahead has 10 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Tuesday, Jul 22 (D63 at 720 kbps), Wednesday, Jul 23 (D14), Friday, Jul 25 (D14 at 720 kbps), Saturday, Jul 26 (D43), and Sunday, Jul 27 (D14 at 720 kbps). The following passes will be carried out at 160 kbps: Monday, Jul 21 (D54), Thursday, Jul 24 (D55), Saturday, Jul 26 (D54), and Sunday, Jul 27 (D55). * Behind has 12 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Monday, Jul 21 (D43 at 720 kbps and D63), Tuesday, Jul 22 (D14 at 720 kbps), Wednesday, Jul 23 (D14 at 720 kbps), Friday, Jul 25 (D63), and Saturday, Jul 26 (D14 at 720 kbps). The following passes will be carried out at 160 kbps: Thursday, Jul 24 (D54), Friday, Jul 25 (D24), Saturday, Jul 26 (D55), and Sunday, Jul 27 (D54). Week 31 (Jul 28-Aug 3) * The HGA angle on Ahead is expected to reach the soft stop on July 28. After this, the telemetry signal will start to drift off the center of the main lobe, and the achievable telemetry rate will start to drop. During week 32, the maximum telemetry rate will still be 720 kbps. This drops to 480 kbps in week 33, and 360 kbps in week 34, after which the spacecraft will switch to side lobe 1. There are two 34 meter supports during week 32 which will be at 96 kbps, on Aug 6 and 9. After that, only 70 meter supports will be used. * C&DH flight software version 3.2.4 will be written to EEPROM copy 1 on Ahead on Jul 29. * The 65th momentum dump on Behind will be carried out on Jul 28, with ignition at 19:45 UT. This is earlier than usual due to schedule constraints. * A 3 hour Project Interface Test (PIT) will be carried out on Behind with station 35 on Jul 30. There will be no instrument commanding or SSR playback during this pass. * The RF margin using the 70 meter stations has been reevaluated, and it has been determined that the 720 kbps rate can be used routinely when on the main lobe. From this point on, this rate will be used for all Behind passes until the HGA soft stop limit is reached. * Ahead has 10 passes during the week, and overall coverage is nominal. There is one pass at 720 kbps, one pass at 480 kbps, one pass at 240 kbps, six passes at 160 kbps, and one pass at 120 kbps. * Behind has 10 passes during the week, and overall coverage is nominal. There are five passes at 720 kbps, and five passes at 120 kbps. Week 32 (Aug 4-10) * The 70th momentum dump on Ahead will be carried out on Aug 4, with ignition at 18:00 UT. * Ahead has 10 passes during the week, and overall coverage is nominal. There are seven passes at 720 kbps, one pass at 240 kbps, and two passes at 96 kbps, on Aug 6 and 9. * Behind has 10 passes during the week, and overall coverage is nominal. There are five passes at 720 kbps, three passes at 240 kbps, one pass at 160 kbps, and one pass at 120 kbps. Week 33 (Aug 11-17) * Head will be at aphelion on Saturday, Aug 16. It has not yet been decided whether a SECCHI stepped calibration roll will be performed. * Ahead has 8 passes during the week, all at 480 kbps, and overall coverage is nominal. * Behind has 13 passes during the week, and overall coverage is nominal. There are three passes at 720 kbps, one pass at 240 kbps, two passes at 160 kbps, and seven passes at 120 kbps. Other * A question was raised about the post-momentum dump report for Ahead on Jul.7. The report is forthcoming. Not all the usual telemetry packets were downloaded due to the reduced telemetry mode. * There was some discussion about the spooler buffer queues, and how it affects SECCHI telemetry during side lobe operations. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 29: M Jul 14 (195) Ahead: IMPACT/SIT HV ramp-up complete T Jul 15 (196) Behind: SECCHI stepped calibration roll, 04:35 UT Behind: HGA calibration, 13:00 UT W Jul 16 (197) T Jul 17 (198) Ahead: Project interface test with new 34 meter station D35 F Jul 18 (199) S Jul 19 (200) S Jul 20 (201) ------------------------------------------------------------------------------- Scheduled activities for Week 30: M Jul 21 (202) T Jul 22 (203) W Jul 23 (204) T Jul 24 (205) Behind: Project interface test with new 34 meter station D35 F Jul 25 (206) S Jul 26 (207) S Jul 27 (208) Behind: Return-to-service test with D26 ------------------------------------------------------------------------------- Scheduled activities for Week 31: M Jul 28 (209) Behind: Momentum dump, 19:45 UT T Jul 29 (210) W Jul 30 (211) Behind: Project interface test with new 34 meter station D35 T Jul 31 (212) F Aug 01 (213) S Aug 02 (214) S Aug 03 (215) Notes: * Ahead is expected to reach the soft stop on the HGA angle on July 28. The telemetry rate will slowly drop after this. ------------------------------------------------------------------------------- Scheduled activities for Week 32: M Aug 04 (216) Ahead: Momentum dump, 18:00 UT T Aug 05 (217) W Aug 06 (218) T Aug 07 (219) F Aug 08 (220) S Aug 09 (221) S Aug 10 (222) ------------------------------------------------------------------------------- Scheduled activities for Week 33: M Aug 11 (223) T Aug 12 (224) W Aug 13 (225) T Aug 14 (226) Ahead: Solar Conjunction Readiness Review F Aug 15 (227) S Aug 16 (228) Ahead: Aphelion S Aug 17 (229) ------------------------------------------------------------------------------- Upcoming events: 2014: * Aug 20 Ahead: Instrument power down * Aug 23 Ahead: HGA on 1st side lobe * Sep 07-Nov 15 Behind: Passage of Comet Siding Spring through HI2-B * Sep 18 Behind: MOps Readiness for S/C Testing Review * Sep 29-Oct 6 Behind: Test of solar conjunction operations * Sep 21 MAVEN arrival at Mars * Oct 17 Behind: Comet Siding Spring encounter with Mars * Oct 20 Ahead: Instrument power on * Oct 23 Behind: Solar Conjunction Readiness Review * Nov 10 Ahead: HGA on 2nd side lobe * Nov 19 Behind: HGA hits soft stop * Dec 1 Behind: HGA on 1st side lobe 2015: * Jan 6 Behind: HGA on 2nd side lobe * Jan 20 Behind: Instrument power down * Jan 22 - Mar 23 Behind: Spacecraft behind Sun * Mar DAWN - Ceres arrival * Mar 22 Ahead: Instrument power down * Mar 24 - Jul 07 Ahead: Spacecraft behind Sun * Mar 30 Behind: Instrument power on * Apr 25 Behind: HGA on 1st side lobe * Jul DAWN - End of nominal mission * Jul 8 Behind: HGA on 2nd side lobe * Jul 14 Ahead: Instrument power on * Sep 24 Ahead: HGA on 1st side lobe * Nov 20 Behind: HGA on 1st side lobe * Dec 29 Ahead: HGA on main lobe, offpoint 1 degree Ahead: SSR playback and reconfiguration, S/C checkout * Dec 31 Ahead: Instrument recommissioning 2016: * Jan 2 Behind: HGA on main lobe Behind: SSR playback and reconfiguration, S/C checkout * Jan 5 Behind: Instrument recommissioning * Jan 27 Both: HGA calibration * Feb 19 Ahead: HGA on main lobe * Mar 16 Both: Post Solar Conjunction Assessment Review * Jul 5 Juno arrival at Jupiter 2017: * Jul 11 Ahead: Switch downlink rate to 160 kbps * Jul 22 Behind: Switch downlink rate to 160 kbps 2018: * Mar 5 Ahead: Mercury transit