THEMIS MISSION PRESHIP REVIEW Thermal Christopher Smith University

THEMIS MISSION PRE-SHIP REVIEW Thermal Christopher Smith University of California - Berkeley MPSR Thermal- 1 UCB, Oct 26, 2006

Thermal Hardware Status Update MPSR Thermal- 2 UCB, Oct 26, 2006

Thermal Hardware Status Update MPSR Thermal- 3 UCB, Oct 26, 2006

Thermal Modeling Status • Second Model Correlation Complete • • All boxes within 5 degrees of test temperatures Thermostat set points verified … except: – – • • • MPSR IDPU and BAU Primary and Secondary IRU Primary and Secondary was verified on P 5 only Heater duty cycles less than 70% Flight Predicts for launch case are complete The remainder are currently running Thermal- 4 UCB, Oct 26, 2006

PFRs and RFAs • Five PFRs closed since PER • • • PFR-186: Thermal Blanket Velcro Adhesion Failure PFR-205: Fuel Line Zone #1 Secondary Thermostat to Low PFR-215: F 3 XPNDR Secondary Setpoints the Same as Primary PFR-225: F 3 MSSS Primary and Secondary service switched PFR-226: P 1 Thermistors BTMPRCSLN 1 and BTMPRCSSVC swapped • RFAs • P 3_PSR_4: Periodic Emissivity Measurements, closed • P 1_PSR_2: Transponder Radiator Resizing, submitted • P 1_PSR_3: Test Versus Flight Radiator Heat Flow Comparison, closed • P 1_PSR_4: Comparison of Pre-test Flight Predicts to Correlated Model, submitted MPSR Thermal- 5 UCB, Oct 26, 2006

Test Facilities Testing took place in JPL chamber #7 • 74”x 134” • Simultaneously accommodated two Themis probes for testing with chamber divider shroud • Gaseous or liquid nitrogen controlled shrouds • GN 2: – 130 to +125 deg C • LN 2: -175 deg C • • MPSR Two TQCMs Nitrogen Vent-back is rate limited 30 power Supplies 168 Type T thermocouple feedthroughs 250 Channel DAQ system 1000 L/sec Leybold and 2000 L/sec Balser Turbo pumps Tank cleanliness certified prior to T-V test Thermal- 6 UCB, Oct 26, 2006

TVAC Flow for P 2 MPSR Thermal- 7 UCB, Oct 26, 2006

TVAC Flow for P 1, P 3, P 4, and P 5 MPSR Thermal- 8 UCB, Oct 26, 2006

Thermal Vac Configuration P 2 Hot Balance #1 MPSR Thermal- 9 UCB, Oct 26, 2006

Thermal Vac Configuration P 1, P 3 -5 Cold Balance #3 MPSR Thermal- 10 UCB, Oct 26, 2006

TVAC #2 Setup MPSR Thermal- 11 UCB, Oct 26, 2006

TVAC #2 Setup MPSR Thermal- 12 UCB, Oct 26, 2006

TVAC #2 Setup MPSR Thermal- 13 UCB, Oct 26, 2006

Test Heaters • 12 test heaters provided for each thermal box • 1 heater for the Antenna Hat Coupler • 1 Heater for the Separation Ring • 1 heater for controlling the beam warm up MPSR Thermal- 14 UCB, Oct 26, 2006

Instrumentation • 168 T-type thermocouples used on P 2 • 80 T-type thermocouples used on P 1, P 3 -5 • 64 x 2 used on the spacecraft • 16 x 2 used for heaters and environment • Transponder fully instrumented • Added thermocouples to the RCS system on P 3 MPSR Thermal- 15 UCB, Oct 26, 2006

P 2 TVAC Results After 1 st Correlation MPSR Thermal- 16 UCB, Oct 26, 2006

TVAC Hot Balance Results Before 2 nd Correlation MPSR Thermal- 17 UCB, Oct 26, 2006

TVAC Cold Balance Results Before 2 nd Correlation MPSR Thermal- 18 UCB, Oct 26, 2006

Combined Probe Correlation Changes MPSR Thermal- 19 UCB, Oct 26, 2006

Combined RCS Correlation Changes MPSR Thermal- 20 UCB, Oct 26, 2006

Other Changes • Increased transponder radiator size by 30% to match hardware modifications • Heater power applied as a function of bus voltage • Added heat leak from sun sensor to thermal box corner panel • Ran two separate cold balance cases to account for different top plate temperatures in actual test • Moved several Thermostat node locations to better reflect as installation photographs • Added Thermostat masses on RCS Fuel Lines Heater Zones (12 grams per TSTAT) • Removed Line 1 heater service from service valve TSTAT node MPSR Thermal- 21 UCB, Oct 26, 2006

TVAC Hot Balance Results After 2 nd Correlation MPSR Thermal- 22 UCB, Oct 26, 2006

TVAC Cold Balance Results After 2 nd Correlation MPSR Thermal- 23 UCB, Oct 26, 2006

Test Heater Power Summary MPSR Thermal- 24 UCB, Oct 26, 2006

Anomalies During Test TVAC 1 • PFR-205, Closed: Fuel Line Zone #1 Secondary Thermostat to Low • Heat leak to bottom deck caused TSTAT to appear to be tripping at a low temperature when it was functioning normally. However this exposed a real cold spot in the RCS fuel line 1. Fly As Is. Only presents a problem in long eclipses when the primary heater service has also failed. TVAC 2 and 3 • • • PFR-215, Closed: F 3 Transponder Secondary Setpoints the Same as Primary • Fly As Is PFR-225, Closed: F 3 MSSS Primary and Secondary service switched • Fly As Is PFR-226, Closed: P 1 Thermistors BTMPRCSLN 1 and BTMPRCSSVC swapped • Database Updated to swap mnemonics MPSR Thermal- 25 UCB, Oct 26, 2006

THERMAL BACKUP SLIDES MPSR Thermal- 26 UCB, Oct 26, 2006

Thermal Testing History MPSR Thermal- 27 UCB, Oct 26, 2006

Thermal Cycle Accumulation Individual Instrument TVAC (2 Cycles) Instrument Suite TVAC (6 Cycles) Probe Level TVAC (4 Cycles, 3 Balance Points) Individual Probe Component TVAC (8 Cycles) MPSR Thermal- 28 UCB, Oct 26, 2006

Thermal Vac Testing History Instruments MPSR Thermal- 29 UCB, Oct 26, 2006

Thermal Vac Testing History Instruments MPSR Thermal- 30 UCB, Oct 26, 2006

Thermal Vac Testing History Suite and IDPU MPSR Thermal- 31 UCB, Oct 26, 2006

Thermal Vac Testing History Mag Booms MPSR Thermal- 32 UCB, Oct 26, 2006

Thermal Vac Testing History SPB MPSR Thermal- 33 UCB, Oct 26, 2006

Thermal Vac Testing History AXB MPSR Thermal- 34 UCB, Oct 26, 2006

Thermal Vac Testing History Probe Components MPSR Thermal- 35 UCB, Oct 26, 2006

Post TVAC 1 Correlation Changes and Data MPSR Thermal- 36 UCB, Oct 26, 2006

P 2 TVAC Results Before Correlation • Comparison of the test data with test predicts show most components are within 5°C of test predicts for Hot and Cold Balance Cases • The Survival Balance Case (Cold 2) results indicate that the model is conservative on the cold side which means that flight heater powers will be less than predicted. MPSR Thermal- 37 UCB, Oct 26, 2006

Correlated Interface Conductances MPSR Thermal- 38 UCB, Oct 26, 2006

Correlated Blanket e* MPSR Thermal- 39 UCB, Oct 26, 2006

Correlated Thermostat Set Points MPSR Thermal- 40 UCB, Oct 26, 2006

Other Changes • Added Thermostat masses on RCS Fuel Lines Heater Zones (12 grams per TSTAT) • RCS Max Heater Power multiplied by 1. 375 (Accounts for 33 V Bus instead of 24 V) • Adjusted RCS Latch Valve, P-Ducer and Solenoid Valve MCp values to account for single node model (FAC 0. 2). • Adjusted Sun Sensor outer face emissivity from 0. 2 to 0. 8 (accounts for black anodized Baffles) MPSR Thermal- 41 UCB, Oct 26, 2006

P 2 TVAC Results After Correlation MPSR Thermal- 42 UCB, Oct 26, 2006