1. FIELDS MEP Thermal Vacuum Cycling iPER
Gayle K. Martin
Brent Mochizuki
Sasha Siy
Bill Donakowski
Steve Marker
January 26, 2017

2. Contents Objectives and Summary Thermal Design
Mechanical Test Configuration
Electrical Test Configuration
Thermocouple Locations
Test Profile
Status

3. Objectives and Summary
Test Objectives
Qualify the flight model of the FIELDS MEP (Main Electronics Package)
Verify that the MEP unit can bear the temperatures
Provide workmanship and performance verification by stressing the components to flight allowable temperatures
Test Summary
Component temperatures will be tested to 10°C beyond flight model predicts (to flight allowable temperatures)
1 survival and 6 operational thermal cycles will be complete in vacuum
CPTs will be conducted at the first and last operational cycles at cold and hot temperatures
LPTs will be conducted for all other operational cycles
2 cold/hot starts

4. MEP Thermal Design
Thermally coupled to spacecraft conductively and radiatively
Conductively coupled to deck with thermal gasket (hard mounted to mounting plate in test)
High emissivity external surface (black paint)
Individual electronics frames with each board coupled to the frame
Thermal parts
Dedicated louvered radiator
No heaters or MLI
Thermistor Honeywell 705 (S/C monitored)
Board level thermal analyses and tests complete
AEB (2), DCB/RFS, DFB, MAG (2), TDS, LNPS(2)

5. Mechanical Test Configuration Chamber
The MEP flight unit will be tested in the UCB/SSL Bayside thermal vacuum chamber
There are two temperature zones for the TV test
Chamber baseplate (heating & cooling)
Chamber shroud (heating & cooling)
Bayside chamber at UCB/SSL feedthrough port and thermal control rack
Bayside chamber at UCB/SSL with aluminum baseplate and shroud

6. Mechanical Test Configuration Hardware
The flight unit will be fully assembled
The MEP will be hard-mounted (bolted) to a mounting plate then bolted to the chamber baseplate
A “shelf” will be used to accommodate the instruments and harness
The following instruments will be inside the chamber for the test
FM V5
EM SCM
4 EM V1234 preamps
The following instruments will be outside the chamber
FM Mag-o in can
FM Mag-I in can`
MEP
SCM V5
shelf
V1 EM
V2 EM
V3 EM
V4 EM
Under shelf V1 V2 V3 V4
Schematic from front of chamber
Schematic of components in test chamber as shown from top.
Zone 1: Shroud
heating & cooling
Zone 2: Baseplate
Mounting plate

7. Electrical Test Configuration
Electrical configuration
Instruments internal to the chamber will be connected directly to the MEP
The harness will be connected via DB25 and BNC feedthroughs in the Bayside chamber
V1234 & V5 stimulus will be connected to the Stim Rack via BNC
Electrical isolation
V5 will be electrically isolated with ChoTherm in the same configuration as the V5 TV configuration
The V1234 EM preamps will be grounded to the baseplate with grounding wires
Thermal control
The flight MEP will be controlled and monitored via thermocouples and AnaWin2 controller
Electrical configuration of the MEP test. Note on V1 is illustrated but the test includes V1234 EM units.

8. Thermocouple Locations
Thermocouples will be mounted along the flight unit and instruments internal to the chamber to verify temperatures during thermal cycling
The internal thermistor will verify that the temperatures have stabilized during instrument operation (not available during survival) 3 4 5 6 7 8 9
TC #
Location  1
Baseplate  2
Shroud  3
MEP top (F) 4
MEP top (B) 5
MEP side 1 6
MEP side 2 7
MEP side 3 8
MEP side 4 9
MEP mounting plate 10
EM V1 preamp 11
EM V2 preamp 12
EM V3 preamp 13
EM V4 preamp 14
FM V5 preamp 15
EM SCM 15 14

9. Test Profile
The test duration for the combined thermal cycling test will take ~7 days (with 4 hour soaks)
Duration includes set-up and take-down time
Instrument functions
Pre-test functional
Hot and cold operation CPTs (op cycles 1 and 6)
Hot and cold operation LPTs (op cycles 2 through 5)
Post-test functional
Test parameters
The transition rate of the instrument is not to exceed 3°C per minute
Start of soak is defined when the control temperature is within 1°C of the test temperature
Soak is defined as a minimum of four hour at case temperatures with a change in temperature of ±1°C
Temperature set-points for each case
Survival = -30°C to 65°C
Operational = -25°C to 60°C
The preamps in the chamber are qualified beyond the MEP set-points
Temperature profile on following slide
TQCM measurement will be made at the end of the test with the MEP followed by a background measurement without the MEP
Future vacuum testing
Additional vacuum exposure will occur on the flight hardware during Observatory level S/C test

10. Test Profile Operational TQCM Turn-on Turn-off Cold turn-on CPT
Survival
Operational
TQCM
Cold turn-on
CPT
Turn-on
Turn-off
LPT
LPT
LPT
LPT
LPT
LPT
LPT
LPT

11. Status Mounting hardware Instruments are ready and available Harness
Mounting plate and hardware clean & ready
Shelf for housing V1234 preamps will use existing GSE
Instruments are ready and available
V1234 EM preamps & housing x4 (no mounting hardware)
SCM EM with mounting plate and hardware
V5 FM with mounting plate, ChoTherm and hardware
Mags (external to chamber in cans)
Harness
Test harness ready with exception of the few identified in electric schematic that need to be remade
Harness needs cleaning
Ground straps
All hardware in the chamber has been verified for vacuum compatibility and temperature limits

12. Back-up

13. Handling & Contamination Control
All test articles and test hardware to be bagged and kept in clean room
Personnel are to handle only with appropriate gloves and contamination gowning
EMECP specifications shall be practiced during flight hardware handling, test set-up and test operations
Contamination control of the instrument must follow the specifications in the SPP-FIELDS Contamination Control Plan 

14. Test Abort, Real Time Activity Assessment and Success/Failure Criteria
Minor anomalies will be evaluated and fixed or alleviated in an attempt to continue testing
Examples of minor anomalies include temporary loss of thermocouple, minor problems with hardware (cable movement) or problems with vacuum facility
Response to minor anomalies will be made by Test Conductors at test site
Significant anomalies will result in abort of further testing
The UCB Test Engineer has the authority to stop testing if deemed damage may be occurring to the hardware, the test equipment functioning is suspect, output data is questionable, or test is not compatible with this procedure
All anomalies shall be reported as part of standard Project Problem/Failure Reporting.
Success/Failure Criteria
Adequate temperature data collected at steady state from all test cases
Meet all S/C requirements

15. MEP Other Thermal Testing
Completed thermal tests
ETU test
Board testing
Future thermal tests
Thermal balance test on boom during SPP Observatory test estimated 12/2017

16. Design and Test Temperature Requirements
Non-operational survival test limit
5°C
Operational Testing &
Flight allowable limit
10°C
Analytical & design margin
Operational prediction
Maximum expected T-range
-30°C -25°C -15°C °C °C 65°C
Maximum expected T-range
MEP

17. MEP EDTRD Thermal Requirements
Complete
Description
0179
Throughout thermal balance and thermal cycle testing, each instrument subsystem or instrument component shall be powered unless there is an identified potential for damage and a waiver has been obtained from APL
0186
Instruments shall be designed and tested to the thermal interfaces listed in Table 5-2
0189
Instruments shall complete a successful thermal vacuum flight qualification testing program prior to delivery to the spacecraft
0190
Testing program shall consist of thermal vacuum balance and thermal vacuum cycle
0191
All instruments thermal test plans shall be provided to the SC thermal engineer for review and approval
0192
Flight predictions shall demonstrate at least 10°C of margin within the instrument operational or survival test temperatures with the exception that for active heater control, 5°C of temperature margin is acceptable at the lower test limit
0195
The thermal cycling that all thermal hardware works as expected hardware for these instruments forgoing the thermal balance test shall demonstrate in thermal
0207
Instrument thermal vacuum cycle tests do not have to maintain the isolated coupling used during thermal balance. This should decrease transition time between cycles, thus total test time. Instrument component temperatures shall be based on flight model predictions if the isolation coupling is not flight-like
0208
Instrument component temperatures shall be tested to 10°C beyond flight model predictions
0209
Flight model testing shall complete six operational and one survival cycle
0212
CPT’s shall be conducted during instrument level TV testing
0213
Minimal functional tests shall be performed at all remaining plateaus if no CPT performed