1. THEMIS MISSION PRE-SHIP REVIEW
Vibration, Acoustics, & Spin Balance
David Pankow
University of California - Berkeley

2. … now how should I fill this 40 minutes
GO FOR LAUNCH !
… now how should I fill this 40 minutes

3. Overview Topics Overview
5-50 Hz Pre-Test of Probe Carrier with Mass Dummies
5-50 Hz Test of Probe Carrier Assembly (Flight Probes)
MECO Transient Documentation
Acoustic Test of Probe Carrier Assembly
Spin Balance & Mass Properties of all Probes
PCA Spin Balance Planning for ASO

4. Vibrations Background
Probes were “Well Behaved”
Lateral Axes (X shown)
Most Q’s were < 15
Probe antenna Q  25
Thrust Axis (Z)
Q’s were mostly below 10

5. Vibrations Background
PCA was “Very Lively”
Lateral Axes (X shown)
Consistent with FEM & CLA
Top Probe Q  60-70
“Twisting” Petals Q  20-30
“Flapping” Petals Q  20-30
All were Non-Linear
Crosstalk 1st Peaks  Input
Thrust Axis (Z) was “Quiet”

6. 5-50 Hz Pre-Test of Probe Carrier with Mass Dummies
Sine Sweep
5-50 Hz Pre-Test of Probe Carrier with Mass Dummies
Rationale: Not a required test, suggested by GSFC/AETD
Prior PSS Quals all between stiff plates, Petal Flex was a concern
Qual PSS was subjected Limit Load Sine Burst, strength should be OK
80 kg Probes lack 50 kg Fuel in PCA test (insufficient loading)
Prior FEM indicated Petal “Twist Mode” was worst case
X direction PCA shake w/ QM PSS on Probe E Mass Dummy
PSS Loading Goal is 125% of FDLC RSS moment
Procs: Thm-mint-proc-049 rev 4; SAI-TM-3068; JPL-144-D-V
Test Report: SAI-TM-3068 to GSFC for review
Status: complete
Additional Information
Very Good Rehearsal for upcoming PCA test (after 8 tries)
Post Test QM PSS Pyro Release & Inspection - OK

7. 5-50 Hz Test of Probe Carrier Assembly (Flight Probes)
PCA Sine Sweep
5-50 Hz Test of Probe Carrier Assembly (Flight Probes)
Rationale: Required by NASA & Boeing
Often considered the “Dress Rehearsal” for Flight
Procs: Thm-mint-proc-049 rev 6; SAI-TM-3075 ;JPL-144-D-V
Report: SAI-RPT-788 to GSFC, KSC & Boeing for review
Status: complete
Additional Information follows
Quick Look Results
1st MODES:
Top-26.5 Hz ; Petal Twist-31 Hz (pairs); Petal Flap-38 Hz (pairs)
PEAK LOADING GOALS: 125% of FDLC PSS RSS moment
(Top) 86%; (Flap) 94%; 93%; (Twist) 99%; 96%

8. PCA Sine Sweep 5-50 Hz PCA Sweep Lateral Sine Sweeps
Data reflects PCA Behavior
Qtop ~ 60-70; Qpetals ~ 20-30
No probe resonances in this range
M+P Controller Tracking

9. MECO (main engine cut off) transient documentation
MECO EVENT
MECO (main engine cut off) transient documentation
GOAL: document previous tests to projected MECO levels
2 Stage Delta MECO Sine Input: g lateral; 0.5g axial
Opening Comments on Prior Test Data
Themis PCA showed NO MAJOR RESONANCES in this range
Any First Occurrence in our accumulated Test Data should be Adequate
Demonstration
Graphic “Quick Look” summary results & table on the subsequent pages
All Vibration testing raw “CSV” data is posted at:
ftp://apollo.ssl.berkeley.edu/pub/ME_Archives/Themis_I&T_procedures

10. MECO EVENT

11. MECO EVENT

12. MECO EVENT

13. MECO EVENT
STATUS: UCB draft to GSFC & KSC – KSC would like all boxes listed in this table

14. Acoustic Test of Probe Carrier Assembly
PCA Acoustics
Acoustic Test of Probe Carrier Assembly
Rationale: Required by NASA & Boeing
Procs: Thm-mint-proc-061; SAI-spec-1164; JPL-144-DA
Test Report: Thm-mint-rpt-061 to GSFC, KSC & Boeing
Status: complete
Additional Information Follows

15. PCA Acoustics
Tabular Summary of Measured Responses
Test Chamber Input

16. PCA Acoustics
Response Plots: Solid – Random Input; Jagged – Acoustics Response

17. PCA Acoustics SST Grms Response Compared
right: ETU random; 18.3 in / 42 response
below: P-2 random 4.43 in / 3.29 res.
below right: Acoustics 4.1 res. (P-1)
4.0 res. (P-5)

18. PCA Acoustics
Boeing provided hardware NTE’s

19. PCA Acoustics Measured Extreme Peaks in Vibration & Acoustics Testing
…from PER
NEW DATA !

20. Spin Balance & Mass Properties of All Probes
Probe Spin Balance
Spin Balance & Mass Properties of All Probes
Rationale: Science Rqm’t: CG < 0.18” ; PA offset < 1
Procs: Thm-mint-proc-049; SAI-plan-0731; ManTech-09PC-WI58 Rev.4
Reports: ATAC (ManTech); Thm-mint-rpt-049 (UCB)
Status: complete
Additional Information Follows
Common Set of Balance Masses & Mass Properties was Adequate
FOT will need to Track Fuel Use, as Previously Planned

21. Probe Spin Balance Mag Boom Simulator Masses Review
Static Balance drives X,Y cg to 0,0
Dynamic Balance drives Lateral POIs (Ixz, Iyz) to zero
Find a set of masses that make the MB’s look deployed
All other measured mass properties have to be corrected
Independent Solutions by 3D CAD & 1st Principals
Solid Works model used for MB parts fabrication, reviewed by G.Dalton
Excel model assembled a set of point & distributed masses (ftp posted)
Continued Validation Efforts
Mass information checked against Build Logs
Locations (dimensions) from Probe CMM data & MB deployment tests
Swales agrees with our methods (but can’t vouch for our first hand data)
AXB’s & SPB’s use this same mass & dimension approach
Lateral POI’s are the “new wrinkle” for the Mag Booms.

22. Probe Spin Balance

23. Probe Spin Balance
On Orbit Spin Axis Uncertainties

24. PCA Spin Balance Planning
ASO Spin Balance
PCA Spin Balance Planning
Rationale: Required by Boeing for STAR-48 1 Hz Spin
Static Balance < 0.05 inch
Dynamic Balance < 1/4 (P.A. offset)
Procs: Thm-mint-proc-067; SAI-plan-0794; ASO-M0006 rev A
Status: ASO’s proc is long standing, UCB proc in draft form
Additional Information: no identified issues
Adaptor Plate & Balance Mass Kit are both In-house