THEMIS IIRT PRE-SHIP TELECON SYSTEMS OVERVIEW Ellen Taylor University of California - Berkeley

1. THEMIS IIRT • PRE-SHIP TELECON • SYSTEMS OVERVIEW • Ellen Taylor • University of California - Berkeley

2. Overview • Systems Update • Verification Status • Mission Readiness Testing (Mission Simulations) • Operating Hours • Procedure Status • Problem Failure Reports (PFRs) • PFRs Opened/Closed since Mission Pre-Ship Review • PFR 229 Memory Scrub Errors • System RFAs • MPSR #3 Verification and Control of Enable/Arm Plugs • Probe Bus #1 PSR 6 Energy Balance (Update w/ flight correlated thermal model)

3. MRD Verification Status • Three pending requirements closed out since Mission PSR in October • Verification activities for all remaining pending requirements are planned as part of normal course of Launch Site Activities

4. MRT Summary • Mission Readiness Testing (MRT) • 64% completed at MPSR, 84% now complete • Still on track to complete >90% by L-2 months (configuration freeze)

5. Operating Hours • Power Log –Hours for Integrated Probe System: • Components accumulated additional 500-800 hours run time prior to integration. • Failure Free Hours: Hours accumulated on core system after return of transponder and BAU during mission integration. • Late Instrument Swaps: • Spare SST on F1 swapped in prior to TVac (>100 hours gained on integrated system) • Spare SCM on F1 swapped in early October (>100 hours gained at component level TV prior to integration onto Probe, >100 hours gained on integrated system) • EFI re-work on F1-F5 completed in November (~90 hours gained after re-integration) • Thermal Vacuum Hours: 120-150 failure free hours were accumulated during TVac Approximately 50 hours expected at launch site, bringing total failure free hours close to 350 prior to launch

6. Procedure Status • All procedures have been provided to KSC as listed below • All Hazardous procedures have been reviewed by GSFC and UCB Safety except RF Chirp Test

7. PFR Summary • PFR Statistics – 4 PFRs CLOSED since MPSR. No PFRs are currently OPEN. • PFR 229 Memory Scrub Errors: OPEN at MPSR, since CLOSED. • PROBLEM: SC Event Message: CheckSum (CS) Memory Scrub Failure logged during maneuver simulations on the Probe and FlatSat • RESOLUTION: Event Message indicates Bulk Memory Scrub failure. Single bit error is found and corrected on-board. No adverse affects have been noted. Problem has been recreated on FlatSat West and East and is understood. One line code fix has been implemented in next version of code. However, easy work-around to not use clear filter table command implemented (use of command was never planned). Therefore, it was determined that code update at this point was not necessary. • PFR 181 EFI Imon: Re-Opened and Closed. Further discussed by J. Bonnell. • PFR 206 AXB Temp Sensor: Re-Opened and Closed. Further discussed by J. Bonnell. • PFR 232 AXB Contamination: Opened during EFI Re-work. Further discussed by J. McCauley

8. MPSR RFA #3 TITLE:Verification and Control of Enable/Arming Plugs RFA CODE: MPSR #3 REQUESTED BY:R. Schnurr SPECIFIC REQUEST: Create a plan to verify and control enable/arming plugs used on the spacecraft. SUPPORTING RATIONALE (ISSUE/PROBLEM):Not clear at review that a coordinated plan exists for verification and control of arming plugs RESPONSE: Use of all enabling plugs have been tracked throughout Integration and Test using Red/Green Tag Item Spreadsheet (see attached). Spreadsheet is appended to as-run procedures for each major environmental test or configuration change. Red/Green Tag boxes include all enabling and arm plugs for each Probe and are clearly labeled with compartment assigned for each item. Flight plugs were used during integration at UCB to test all functions locked out by enabling plugs (Boom deploy, ESA high voltage, IDPU actuator power, RCS thrusters/catbeds) except Pyro actuation. Pyro arm plug was installed and voltage verified at Pyro connector for RCS Interface Verification Test (IVT) at Swales per SAI-PROC-1502. Pyro arm plug will put in line with NSI simulator and retested prior to final installation at ASO per THM-MINT-PROC-105 Rev C. All flight plugs will be inspected and pin continuity/isolation checked prior to final installation on Probes per THM-MINT-PROC-053 Probe Close-Out Procedure.

9. MPSR RFA #3

10. Probe Bus #1 PSR 6 TITLE:Energy Balance at Deep Eclipses RFA CODE: Probe Bus #1 PSR 6 REQUESTED BY:R. Schnurr SPECIFIC REQUEST: Provide Energy Balance Analysis RESPONSE: Tech Memos SAI-TM-2520 (F2), 2971 (F3), 3023 (F4) and 3033 (F1 and F5) Power Balance Analysis Results and Requirements Verification attached. Tech Memos provide a summary of the Swales analysis completed for worst-case eclipses (3 hours). Initial analysis was done with heater power predictions from uncorrelated thermal model and showed a EOL margin of approximately 3.5W or 10%. Since the MPSR, heater power predictions from correlated thermal model have been completed for over 30 cases for comparison (various sun aspect angles, orbits and eclipse durations). Comparison case from Swales showed uncorrelated model heater power predict of 9.5 Watts. Re-correlated model (with RCS heat leaks and larger radiator) showed heater power predict of 11.2 Watts, or an increase of 1.7W, reducing the EOL margin to approximately 5%. As stated at the MPSR, additional margin can be easily recovered by duty cycling the instruments during the long eclipse season in the second year of the mission.

11. Probe Bus #1 PSR 6 TITLE:Energy Balance at Deep Eclipses RFA CODE: Probe Bus #1 PSR 6 REQUESTED BY:R. Schnurr SPECIFIC REQUEST: Provide Energy Balance Analysis RESPONSE: Tech Memos SAI-TM-2520 (F2), 2971 (F3), 3023 (F4) and 3033 (F1 and F5) Power Balance Analysis Results and Requirements Verification attached. Tech Memos provide a summary of the Swales analysis completed for worst-case eclipses (3 hours). Initial analysis was done with heater power predictions from uncorrelated thermal model and showed a EOL margin of approximately 3.5W or 10%. Since the MPSR, heater power predictions from correlated thermal model have been completed for over 30 cases for comparison (various sun aspect angles, orbits and eclipse durations). Comparison case from Swales showed uncorrelated model heater power predict of 9.5 Watts. Re-correlated model (with RCS heat leaks and larger radiator) showed heater power predict of 11.2 Watts, or an increase of 1.7W, reducing the EOL margin to approximately 5%. As stated at the MPSR, additional margin can be easily recovered by duty cycling the instruments during the long eclipse season in the second year of the mission.