1. FIELDS SCM Thermal iPER
Gayle K. Martin
November 11, 2016

2. SCM Thermal Cycling Objectives and Summary
Test Objectives
Qualify the flight model of the SCM instrument
Verify that the SCM unit can bear the temperatures
Provide workmanship and performance verification
Component temperatures shall be tested to 10°C beyond flight model predicts
Test Summary
Twelve thermal cycles will be complete in air (in lieu of 6+1 vacuum cycles approved via waiver)
CPTs will be conducted at the first and last cycles at cold and hot temperatures
LPTs will be conducted for all other operational cycles

3. SCM Thermal Cycling Test Configuration
Hardware configuration
The flight units will be fully assembled, flight heaters will be included with the flight unit
The SCM will not be blanketed
Chamber configuration
The SCM flight units will be tested in the UCB/SSL Sun Systems MODEL EC1x Environmental chamber
There is a single temperature zone for the thermal cycling test
Electrical configuration
The harness will be connected to a feedthrough to connect to the SCM GSE external to the chamber
The flight instruments will be controlled and internal thermistors monitored via the SCM GSE connected externally to the chamber
SCM flight unit
Test harness schematic

4. SCM Thermal Cycling Test Configuration
Thermocouples will be mounted along the flight unit, and harness to verify temperatures during thermal cycling

5. SCM Thermal Cycling Test Profile
The test duration for the combined thermal cycling test will take ~5 days (assuming 4 hour soaks) including set-up and take-down time
Instrument functions
Pre-test functional
Hot and cold operation CPTs (cycles 1 and 12)
Hot and cold operation LPTs (cycles 2 through 11)
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 cycle case -60°C to 80°C
Note: heater setpoint is -50°C
Future vacuum testing
Vacuum exposure will occur on the flight hardware
The SCM assembly will “ride-along” with the FIELDS MEP in thermal cycling
6 operational cycles from -25°C to 60°C
1 survival cycle from -30°C to 65°C

6. Back-up

7. Risk Assessment (Waiver)
The FIELDS EM SCM saw vacuum testing in sensor level TB, instrument-level TV as well as TB testing of the mag boom – all with nominal results.
The FIELDS FM SCM will see vacuum testing in instrument-level thermal vacuum cycling.
The FIELDS FM SCM will see vacuum testing in spacecraft-level thermal balance and spacecraft-level thermal vacuum cycling.
FIELDS believes that doing thermal cycling in air would actually be more effective at revealing workmanship problems in a limited duration test.
The SCM sensor includes a number of EEE parts – all fully encapsulated in the 3d-Plus preamplifier structure.
As such, testing in air with reasonable dwell times at temperature extremes will give good workmanship results.

8. 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 

9. 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