1. THEMIS INSTRUMENT SUITE
FM4/FM5 PRE-SHIP REVIEW
MAGNETOMETER BOOMS
Paul Turin
Themis Lead ME
University of California - Berkeley

2. Outline
Summary of Current Mag Boom Status
FM4/5 Configuration
End Item Data Package ToC
Requirements
Fulfillment of Requirements
PFR Status
RFAs, Closeouts, Rework, etc.
Appendices (testing info)

3. Mag Boom Status Requirements and Design: Assembly, and Test:
No change to (official) Requirements since MCDR
Changes to Boom design due to other considerations:
Tilt upwards 5 deg (FGM)10 deg (SCM) to reduce S/A shadowing
Required taller frangibolt towers, inclined pivots
Raise boom height above deck to clear higher solar array
Required raising shoulder bases on taller feet
Several more changes needed to fix problems caused by 1st two changes:
Strengthen SCM Frangibolt tower
Strengthen SCM Shoulder Feet Flexures
Replace FR-4 thermal isolators with steel blocks
Redesign shaft retention set screws
Assembly, and Test:
5 flight and 1 flight spare boom sets have completed functional and environmental testing and have been delivered to Suite I&T. Deployments during Suite TV complete.

4. Configuration
Mag Boom Configuration by Serial Number:
FM4 suite contains FM4 FGB and FM4 SCB
FM5 suite contains FM5 FGB and FM5 SCB

5. EIDP

6. Mag Boom Requirements
UPDATE! Ask Ellen about my mods, see if has new version

7. Satisfaction of Requirements
Test
Proof test of graphite tubes
Ambient, 0 rpm deployment test
Sine, Random Vibration test
Thermal vacuum test (cycling + Hot and Cold 1st motion deployments)
15 rpm equivalent drop test
Repeatability test
Torque margin test
Mag alignment verification
Length Measurement
Satisfies Requirement
GEVS
IN.BOOM_4
IN_BOOM_2,4
IN.BOOM_1
Science
IN_BOOM_9,10
All test complete, all booms passed, all results in family
(except FM6, still acceptable)

8. PFR Status PFR Status Title Resolution PFR-025 CLOSED
Cracked feet in SCB frangibolt tower
Replaced DAD Tower
PFR-027
Cracked Base Bracket in SCB
Redesigned tower, used steel washers
PFR-041
Spring spool in SCB base hinge loosened by vibration.
Tightened Spools with new tool to higher torque
PFR-043
Damaged threads in FGB frangibolt ring.
Repaired thread with helicoil. Affects FM6 spare only
PFR-044
Friction increase in hinge mechanism after vibe
Set screw backing out and binding – larger screw used and staked
PFR-053
Increased base hinge friction post vib at qual levels
Bronze on Al galling -- SS shim added for bronze bushing to ride on
PFR-058
SCB connector wire damage
ETU cable too short – Flight long enough
PFR-073
Length Discrepancy between SCM Flight Harnesses
All cut to same length
PFR-077
FM1 FGB Fail to deploy in Cold Vacuum Test
Inadequate firing time for cold temperature – worked fine with correct time
PFR-078
Cable for FGM Mag Boom is discolored
Contamination analyzed by GSFC determined not a contamination hazard
PFR-079
FM2 FGB fails cold deployment 6/21/05
PFR-080
FGB 2 fails cold deployment 6/22/06
Frangibolts did fire, Operator forgot to remove tape holding booms together
PFR-086
Incorrect Deployment Angles in FGM Design
Shims added to get correct angles
PFR-126
Magnetometer Mount Flatness and clocking
Shim to get mounting flat and clocking correct

9. RFAs, Closeouts, Rework, etc.
No Mag Boom RFAs
No remaining Closeout Items (except shimming)
Rework or replacement of hardware:
Frangibolts connectorized on FGB for easier resetting
Compliance with Test Verification Matrix Complete
Test Margins
Adequate margins at Deployment extremes
Torque margin worst-case > 3.3 (reqmt >2)
Survived vibration and thermal limits + margin
Integration with Probe 3,4 Buses
Per thm-mint-proc-026,-027,-037
Units will get 1st motion deployments during probe TV

10. Appendix 1
Vibration Testing

11. FM 6 tested to qual levels, FM 1-5 to acceptance levels
Vibration Testing
Sine Vibration Levels (Ref. Swales SAI-TM-2430-RevD )
FM 6 tested to qual levels, FM 1-5 to acceptance levels

12. Vibration Testing cont.
Random Vibration Levels (Ref. Swales SAI-TM-2430-RevD )
FM 6 tested to qual levels, FM 1-5 to acceptance levels

13. Vibration Testing Status
UPDATE WITH FM 2-6 DTA

14. Appendix 2
Themal Vac Testing

15. Thermal Vacuum Testing
Test temperatures and Profile:
-115C, 4h
75C, 4h
75C, 12h
50C, Hot Deploy
-40C, Cold Deploy
Restow
Qual or acceptance?

16. SCM/FGM Boom Thermal Testing Status
Get updated table from Chris

17. Strength, Repeatability, and
Appendix 3
Strength, Repeatability, and
Torque Margin Testing

18. 15 rpm and Repeatability Test
Booms hung vertically and weighted so that 1g replicates loads caused by spin accelerations, then dropped from angle that gives correct energy at end of stroke to simulate 15 rpm deployment forces. Boom then dropped 5 times and the rest angles were measured, worst-case variations below.

19. 15 rpm and Repeatability Test continued
Drop and repeatibility tests repeated on one unit with angle correction shims to show that shims (added per PFR-086) have no effect on repeatability or strength.

20. Torque Margin test Minimum Torque Margin = 4.3
This test was run to verify adequate torque margin at worst-case joint at worst-case temperature of -8C and worst-case spin rate of 20rpm (bounce during thrust).
Worst-case torque margin of 4.3 meets minimum requirement of 3
Minimum Torque Margin = 4.3
Ts Torque from Spring
Tm Torque from Resistive Force on Force Gauge
Tc Torque from Centripetal Force on Elbow Arm on Elbow Joint
Tf Frictional Torque on Elbow Joint