1. THEMIS MISSION PDRMAG BOOM- 1 UCB, November, 2003 Magnetometer Booms (MAGS) Mission Preliminary Design Review Hari Dharan Space Sciences Laboratory University of California at Berkeley

2. THEMIS MISSION PDRMAG BOOM- 2 UCB, November, 2003 REQUIREMENTBOOM DESIGN IN-7. No component of the Instrument Payload shall exceed the allocated mass budget in THM-SYS-008 THEMIS System Mass Budget.xls Compliance. FGM Boom: 1.27kg Allocated. SCM Boom: 0.68kg Allocated. IN-9. No component of the Instrument Payload shall exceed the power allocated in THM-SYS-009 THEMIS System Power Budget.xls Compliance. Frangibolt: ~26W transient IN-13. The Instrument Payload shall survive the temperature ranges provided in the ICDs Compliance. IN-14. The Instrument Payload shall perform as designed within the temperature ranges provided in the ICDs Compliance. IN-16 The Instrument Payload shall comply with the Magnetics Cleanliness standard described in the THEMIS Magnetics Control Plan Compliance. THM-SYS-002 Magnetics Control Plan. IN-17 The Instrument Payload shall comply with the THEMIS Electrostatic Cleanliness Plan Compliance. THM-SYS-003 Electrostatic Cleanliness Plan IN-18 The Instrument Payload shall comply with the THEMIS Contamination Control Plan Compliance. THM-SYS-004 Contamination Control Plan Mission Requirements

3. THEMIS MISSION PDRMAG BOOM- 3 UCB, November, 2003 REQUIREMENTBOOM DESIGN IN-21. The Instrument Payload shall be compatible per the IDPU-Probe Bus ICD Compliance. THM-SYS-112 Probe-to-FGM Mag Boom ICD. THM-SYS-113 Probe-to-SCM Mag Boom ICD. Verification Matrices to be completed. IN-23 The Instrument Payload shall verify performance requirements are met per the THEMIS Verification Plan and Environmental Test Spec. Compliance. THM-SYS-005 Verification Plan and Environmental Test Specification preliminary draft. Verification matrix to be completed. IN-24 The Instrument Payload shall survive and function prior, during and after exposure to the environments described in the THEMIS Verification Plan and Environmental Test Specification Compliance. THM-SYS-005 Verification Plan and Environmental Test Specification preliminary draft. Verification matrix to be completed. Mission Requirements

4. THEMIS MISSION PDRMAG BOOM- 4 UCB, November, 2003 REQUIREMENTBOOM DESIGN IN.BOOM-1. Mag Boom deployment shall be repeatable to 1 degree Compliance. IN.BOOM-2. Mag Boom stability shall be better than 0.1 degree (includes bus and boom components) Compliance. IN.BOOM-3. Mag Boom deployed stiffness shall be greater than 0.75Hz Compliance. IN.BOOM-4. Mag Boom shall be designed to be deployed between 2 and 15 RPM about the Probe's positive Z axis. Compliance. IN.BOOM-8. The FGM boom shall be approximately 2 meters long. Compliance. IN.BOOM-9. The SCM boom shall be approximately 1 meters long. Compliance. IN.BOOM-12. All deployed booms shall include an inhibit to prevent inadvertent release. Compliance. Boom Requirements

5. THEMIS MISSION PDRMAG BOOM- 5 UCB, November, 2003 Heritage Design construction, and operation based on FAST and Lunar Prospector magnetometer booms Requirements All requirements allocated System Performance Budget, Error Budget Addressed via IN.BOOM requirements in coordination with Swales mechanical group Margins Torque ratio of >3:1 maintained in all moving parts design, to be verified in test program Analytical SF >1.4 x limit loads for ultimate failure modes for metallic components, >2.0 for composite components Descope Plans SCM not necessary for minimum science

6. THEMIS MISSION PDRMAG BOOM- 6 UCB, November, 2003 Mass budget 27% 15% ICDs substantially complete (available for review) Resolution of TBDs in works – complete by 11/30

7. THEMIS MISSION PDRMAG BOOM- 7 UCB, November, 2003 Overview Components of Mag Booms Elbow Latch FGM Base Hinge/ Frangibolt SCM Frangibolt SCM Base Hinge (similar to FGM Base Hinge) Carbon-fiber tubes FGM: 1.9m SCM: 1m

8. THEMIS MISSION PDRMAG BOOM- 8 UCB, November, 2003 Overview 1.SCM and FGM frangibolts fire. 2.Deployment springs at base hinges deploy booms. 3.Additional kickoff spring at FGM elbow Deployment of Mag Booms

9. THEMIS MISSION PDRMAG BOOM- 9 UCB, November, 2003 Deployment Simulation Simulated in MATLAB Calculates accelerations of each link - based on three link pendulum model Includes latching events, deployment spring forces, and kickoff spring forces Inputs: Spin rate, Spring rates, Moments of inertia, Initial position Outputs: Kinetic Energy, Latch Time, Deployment animation

10. THEMIS MISSION PDRMAG BOOM- 10 UCB, November, 2003 Proposed Design - Frangibolts Frangibolt Implementation TiNi Aerospace’s FC2-16-31SR2, 2200N, 25W Frangibolt Reliable, flight heritage (HESSI, Mars Express, Cloudsat, Coriolis, etc.) Kickoff spring to ensure release from caging tower

11. THEMIS MISSION PDRMAG BOOM- 11 UCB, November, 2003 Proposed Design - Elbow Elbow Latch Features Compact and simple design. Disc springs allow for high force low displacement action Design of shear support with kickoff springs eliminates sticking Allows for zero RPM deployment

12. THEMIS MISSION PDRMAG BOOM- 12 UCB, November, 2003 Proposed Design – Base Hinge Deployment Spring Latch Pin Spring Large Energy Absorption Spring Base Hinge Overview Features Energy absorption Zero Kinetic Energy Latching Deployed Stowed

13. THEMIS MISSION PDRMAG BOOM- 13 UCB, November, 2003 Proposed Design – Base Hinge FGM/SCM Base Hinge Deployment/Latch Sequence: Animation

14. THEMIS MISSION PDRMAG BOOM- 14 UCB, November, 2003 Other design considerations Other considerations ETU testing to verify friction in shaft/clevis and stop rings. ETU testing to verify reliability and repeatability in deployment including thermal considerations. Spin axis/boom bias –Booms are given slight (2-3° TBV) bias out of spin plane –Kinematically defined end position despite unknown satellite spin axis –Angles are exaggerated to illustrate principle

15. THEMIS MISSION PDRMAG BOOM- 15 UCB, November, 2003 Tube Design – NASTRAN Modal Analysis Frequency Spec Mag. Boom stowed stiffness shall be greater than 100 Hz Mag. Boom deployed stiffness shall be greater than 0.75 Hz Current Design Frequency spec is met by current tube layup More detailed NASTRAN work will follow. ETU tube vibration test to verify will be performed in January. 1 st mode shape of stowed FGM outer boom. 1 st mode shape of deployed FGM boom. 1 st mode resonance StowedFGM inner tube168 Hz FGM outer tube157 Hz SCM tube143 Hz DeployedFGM tube10 Hz SCM tube15 Hz

16. THEMIS MISSION PDRMAG BOOM- 16 UCB, November, 2003 Tube Design – Deployment Stresses Deployment stress in the tube was estimated assuming all the kinetic energy was converted to strain energy in the tube at latching. ( Maximum kinetic energy at 15 rpm: SCM base hinge, ~2J, FGM base hinge, ~1J, FGM elbow hinge, ~0.3J) Tube was treated as end loaded, cantilever. For the nominal case(SCM ~2J, FGM~1J), the stresses in the FGM and SCM tubes were below their compressive and tensile strengths. Detailed NASTRAN stress analysis will be performed. Stress @ 15 RPM, Hard Stop Safety Factor FGM-20.2 ksi (-139 MPa)2.7 SCM-40 ksi (-278 MPa)1.4

17. THEMIS MISSION PDRMAG BOOM- 17 UCB, November, 2003 Tube Design Tube/Layup Design considerations Frequency spec. Deployment stresses. Mass allocations. Fabrication Handling. Designed Lay-up [(0/90) T300 / ((0) M60J ) 5 ] s T300 = high-strength carbon fiber/epoxy woven (0.005”/ply), M60J = high-modulus carbon fiber/epoxy tape (0.002”/ply) (to be replaced with lower cost M55J with 5% less modulus) Tube Design Thickness = 0.030 in. Inside diameter = 1.250 in. Effective Modulus = 33 x 10 6 psi (230 GPa) Mass per unit length = 3.2 g/in (1.26 g/cm)

18. THEMIS MISSION PDRMAG BOOM- 18 UCB, November, 2003 Thermal Considerations Thermal expansion effects on dimensional stability of mag booms are expected to be small due to low CTE of carbon fiber tube (expected to be -0.5 ppm/K; Al = 24.7 ppm/K) Thermal stress generation may necessitate Ti-6Al-4V for lower thermal stress. Prototype carbon fiber/Al and Ti joint configurations will be thermal cycled between qual temperature limits and proof tested to evaluate effect of thermal cycling on bond strength. Thermal Analysis (detailed to be performed on final design configuration using NASTRAN) CTE stability in deployed configuration (thermal soak) Thermal stresses and displacements (between M55J deck and base brackets and Frangibolt housing, and between carbon fiber tube and end fittings) Thermal gradient effects –Tolerance effects –CTE stability

19. THEMIS MISSION PDRMAG BOOM- 19 UCB, November, 2003 Fabrication and Assembly Plan Tube Fabrication Bldg 151,Richmond Research Center (RRC). Table rolling process to produce tubes Fiber alignment Use of space qualified pre-preg Rapid production Quick tool change Table RollerShrink Tape WrapperOvenMandrel Puller

20. THEMIS MISSION PDRMAG BOOM- 20 UCB, November, 2003 Fabrication and Assembly Plan Bonding of Tubes Bonding fixture has bolt holes to match location of deck inserts. (Bolt hole pattern will be kept consistent between UCB and Swales via a template) Hinges will be bolted to bonding fixture and tubes bonded. Bldg 151, RRC. Assembly of Hinges, Harness, and Frangibolts Harness will be routed through booms. Frangibolts and their assembly will be attached to the mag booms. Facility in SSL.

21. THEMIS MISSION PDRMAG BOOM- 21 UCB, November, 2003 Test Plan Tube testing 1.25 x Limit Load proof test of each tube Joint testing 1.25 x Limit Load proof test adhesive bond between tube, end fittings and hinges. ETU testing Vibration test with instrument mass simulators. Response to be delivered to FGM/SCM team for flight mag testing. Offloaded deployments on engineering model with mass simulators. Verify deployment margins with reduced load deployments. Flight Unit testing Testing (Offloaded deployment, vibration, thermal vacuum with hot and cold first motion tests, offloaded deployment. All with mag mass dummies). First motion test on S/C to verify mounting.

22. THEMIS MISSION PDRMAG BOOM- 22 UCB, November, 2003 Schedule Design and Analysis Ongoing. Preparing for CDR in Mar/Apr 2004. Fabrication and Assembly Fabrication of ETU Mag Booms: 11/20/03 to 1/20/04 Fabrication of Flight Mag Booms: 3/30/04 to 6/14/04. Assembly of Flight Mag Booms: 6/15/04 to 9/13/04. Testing Tube testing : during ETU and Flight tube fabrication Joint testing : during ETU and Flight Unit assembly ETU testing (week of 2/23/04) Flight Unit testing : 8/10/04 to 9/28/04.