Particles and Fields Package Quarterly Status Review (QSR) January 15, 2013 Dave Curtis, PFP PM
PFP FM Photos SEP EUV PFDPU STATIC SWIA LPW MAG SWEA
PFP Delivery
PFP Installed on Spacecraft SEP 1 MAG 1 LPW 1 EUV LPW 2 MAG 2 SEP 2 SWIA STATIC PFDPU (not shown)
Accomplishments Package integration complete All issues closed (except SWEA) Passed Pre-Ship Review Package delivered to ATLO (except SWEA) Bench test completed Components integrated to spacecraft IPTO & Functional completed Spacecraft Self-Test, Transition SVT, and Science SVT SWEA failed in Thermal Vac (second time) HV discharges damage a preamp, plus some HV instability cold Remained in Thermal Vac to fully characterized the problem Disassembled SWEA for inspection and board-level test Steve Battel came to SSL to participate in inspections, test, and brainstorming FRB held to identify a path forward; details below
Schedule Status PFP delivered to ATLO 11/26/2012 Except SWEA SWEA disassembled and in test/rework: Rework continuing through Jan 16 Reassemble and functional test (in Cal chamber) through Jan 24 Vibration Jan 25 Post-vibe test (in Cal chamber) through Jan 29 Thermal Vac through Feb 8 Final Calibration through Feb 17 ~1 week margin Deliver to LM ~Feb 25.
Schedule
EVM (October report) SPI at 1, consistent with delivery (except SWEA) CPI remains low due to high manpower levels required to overcome problems and press to maintain delivery schedule and recover from SWEA issues SPI / CPI October 2012
ATLO Issues [1] EUV alignment shims EUV needed to be shimmed to meet alignment requirements Shims used did not result in SWEA feet being flat; unit under torque New shim fabricated to make EUV flat Installed 1/15?
ATLO Issues [2] SEP noise Caused by temperature sensor polling Fix is to move temperature sensors outside the sensor Done 1/15? Tested 1/16? A much higher noise rate with a similar characteristic was seen during Science SVT Only seen on the SEP unit which had the heater/temp sensor harness connected Same SEP detectors saw the counts that saw temp sensor switching May be correlated with APP motors May be coming in through noise in the heater or temp sensor returns? Needs testing – early Feb?
ATLO Issues [3] MAG Heater Monitor Used to monitor the MAG sensor temperature when PFDPU is powered off and MAG heater service is ON An analog monitor actually proportional to the heater duty cycle, but can be converted to temperature if you know the bus voltage Measured 2.73V. Based on the measured MAG temperature (21C) and bus voltage (29.8V) we expected 3.07V. 2.73V corresponds to +27C at 29.8V. We believe the cause is that the heater circuit was changed after the calibration coefficients were determined. Unfortunately we did not notice this prior to delivery. We should be able to update the coefficients soon A second temp sensor is monitored by the PFDPU when it is on.
ATLO Issues [4] SASM / LPW Timing SASM restricts solar array switching to a fraction of each second LPW restricts sampling to a different fraction of a second to avoid picking up noise from the array A test of the phasing of the LPW sampling and SASM switching showed a phase error in LPW sampling signal relative to the SASM switching Subsequent bench testing shows the problem is in the LPW sampling and how it reconstructs the SASM switching time LPW bases its sampling on the spacecraft clock, incorrectly assuming that the spacecraft clock time tic occurs at the same time as the 1HZ signal used to synchronize the SASM. LPW can apply an offset to its timing signal to re-align its sampling It appears that the phase between the clocks will be fixed during the mission, and is represented by the subseconds of the spacecraft clock. We should be able to get the subseconds information on the ground during the mission and program the LPW phase accordingly. Alternatively we could do the same in PFP flight software, but that requires a PFP software update. Plan to test this approach this week?
ATLO Issues [5] Missing Time Update PFP occasionally sends ‘Missing Time Update’ status This is because of jitter in when the spacecraft sends the time update command to PFP combined with the fact that PFP runs asynchronously to spacecraft clock This is not a functional problem (PFP knows the correct time), but makes it not possible to know if we are in fact missing time updates or if it is just the jitter A potential solution is for the spacecraft to send time more than once a second, so there is always at least one time update per 1-second interval. This requires a spacecraft flight software change plus a waiver to an ICD requirement which says there will be only one time update per second.
SWEA Issue SWEA failed Thermal Vacuum (second time) Significant Issues: High voltage discharges, resulted in damage to a preamp High voltage instability when cold Analyzer voltage sometimes sagged Issues more prevalent when instrument was cold Discharges and sagging discontinued after many days of operation in vacuum (no issues in last 2 weeks in thermal vac) Working closely with FRB on these issues and their resolution Steve Battel was also able to come out to SSL for a day to helps us out
SWEA Diagnostics After we had learned all we could from thermal vac, FRB agreed to proceed to disassembly / inspection / subsystem bench test Inspection and test found no signs of damage other than preamp Tests of the analyzer by itself show that the MCP detector resistance increases significantly when cold (from 50M to 140M) Tests of High Voltage Power supply show that it is unstable with a 140Mohm load, explaining the instability seen cold Working with the EM HVPS to tune it to operate stably at 140Mohm load Still testing the analyzer voltage to understand the sagging Inspections found several design or workmanship items that could be contributing to the discharges Agreed on a plan forward with the FRB:
SWEA Plan Forward Tune the MCP High Voltage so it is stable at cold temperature load Currently testing proposed solutions on the EM Make a series of adjustments to the system to reduce the risk of discharge and decrease the risk of damage to the preamps in the event of a discharge Add fast protection diodes right at the preamp input Add conformal coat at locations of high field strength to encapsulate the field emission sources Remove a common mode choke that can exacerbate ground bounce during a transient event Reroute harnessing on the HV board to keep wires away from the high voltage components Add a series resistor to the MCP HV output to limit the energy available to a discharge
SWEA Thermal Thermal Vac shows that the system is more likely to have a discharge when cold (though mitigated by the rework above) FRB also agrees with a recommendation to run SWEA warmer to reduce the stresses and risks of high voltage issues Determined how much power it would take to raise the SWEA heater set-point Heater is adequately sized to keep SWEA ~+10C, warmer if we run both heaters at the same time PFP power margin allows us to run the heater with a ~+10C set point. Higher than that would require a waiver to the PFP NTE There is not a clear threshold based on thermal vac data for the optimal SWEA heater set-point, so we have not yet targeted a new set point Will submit a waiver to the ERD to request a higher SWEA heater set-point, and perhaps exceed the PFP NTE power once we decide on a temperature.
SWEA Operational Other operational recommendations: Slow down the last 500V of MCP HV ramp-up, especially when cold. After powering off high voltage, wait at least 15 minutes for the high voltage parts to stabilize before ramping back up again, especially when SWEA is cold. Cycle High Voltage as little as possible. Currently SWEA is planned to be off during deep dips and the large thruster firings based on a 1E-5 Torr pressure requirement. We plan to run a test on the EM similar to what we did for STATIC to verify we can in fact survive a higher pressure; if so that will allow us to avoid those high voltage cycles.
EM Tests We continue to use the EM setup at SSL to verify issues discovered during ATLO We are also running a series of tests on the EM to verify the time-stamping of telemetry and the operation of the Archive system to be sure we fully understand timing and operations. Currently no open Flight Software Problem Reports or Change Requests
Top Risks
Risks List
PFP Mass Waiver approved NTE exceednaces (CCR-650)
Mass Tracking Chart
PFP Power Orbit Average Heater power reduced based on correlated thermal model results, resulting in more power margin. May decide to use that margin to run SWEA warmer (waiver pending).
PFP Power Trend
PFP Data Rate No change
Requirements Verification Status Type # Requirements # Verified FRD 107 86 ERD 106 72 ICD 142 124 FSW – Op 207 FSW - Boot 68 Most Remaining verifications pending SWEA completion One open issue is pointing verifications Looks like we will need to submit a waiver: unable to meet requirements in a few cases based on instrument calibrations Can meet level 1 requirements with expanded pointing uncertainty Verification matrix updated, MAVEN_PF_SYS_033H
Safety and Mission Assurance Quarterly Status Report (QSR) January 2013 Jorg Fischer, PFP MAM 28
SMA SUMMARY Supported the monthly ESD Control survey – no issues Supported the monthly calibration checks – no issues Provided cleanroom support: cleaning of parts, supply, and maintenance, for all MAVEN cleanrooms Alert responses: Updated the alert response database - no impact reports for all December alert items. Continuous inspections of Flight assembly and test areas Provided support for delivery of the instruments to LM Provided support for S/C integration at LM Polymerics: Mix record database, updated. Performed polymeric witness sample testing, filing, inspections, and close-out. Performed FLT document reviews, and updates for the EIDP
SMA SUMMARY Supported the delivery of Flight Instrument to Lockheed Martin, CO and S/C integration activities of the Instruments Cleanroom Training at LMCO Instrument unpacking and set up for post ship CPT’s Instrument Installation oversight Harnessing of instruments General technical and QA support at LMCO Support of SWEA – Tuning efforts, repair/rework, and testing of the SWEA instrument. SWEA HV Board – Post Anomaly Inspections SWEA PreAmp Board – Removed and Replaced all Preamps Assembly and Disassembly Technical activities and Inspection
PFR Detail Updated PFR/NCR/LL data base PFR status report list sent to GSFC - weekly Provided assistance to SSL engineers with PFR form and related item close-out documentation PFR Status (1/10/13): Problem count 132 MRB problems: 87 NCR problems: 40 Closed: 121, Open: 3, VOID:5 Monitor: 3 MAVEN_PFR_059_SWEA_Preamp_Failure MAVEN_PFR_115_SWIA_Vibration_Frequency_Shift MAVEN_PFR_122_SWEA_Vibe_TVac_Issues Open Problems: 3 (1 NCR, 2 PFR) MAVEN_PFR _128_STATIC_RTD_Thermo-couple_test MAVEN_PFR_130_NCR_SWEA_TVAC_Test [in sign-off] MAVEN_PFR_131_SWEA_TVAC_Power_Supply_Instability
SMA Other activities include the normal, ongoing participation in instrument and FRB/MRB meetings, discussions, reviews and comments. SSL SMA provided continued operator training and re-certification services, stockroom, shipping, chemical inventory, ESD control, and safety checks.
SMA SUMMARY – Concerns All PRFs are worked to close and will be addressed at a MRB/FRB closure meeting at the beginning of January All concerns are well understood and are closely monitored by SSL and GSFC QA. Pending – SWEA