THEMIS Instrument CDR 1 UCB, April 19-20, 2004 Magnetometer Booms Critical Design Review Dr. Hari Dharan Berkeley Composites Laboratory Department of Mechanical Engineering University of California at Berkeley

THEMIS Instrument CDR 2 UCB, April 19-20, 2004 Overview Magnetometer Booms System Overview Technical Requirements System Mechanical Design Updates to Analyses Design Margins Mass and Power Test Plan Fabrication Plan Integration Plan Performance Assurance Schedule Parts and Materials Status Contamination Control Problem Areas

THEMIS Instrument CDR 3 UCB, April 19-20, 2004 System Overview Magnetometer Booms Each probe has two magnetometers – Flux Gate Magnetometer (FGM) and Search Coil Magnetometer (SCM). The magnetometers are to be magnetically isolated by suspending via booms from probe. The booms must be stowed to fit the envelope of the probe in. ID carbon- fiber tubes. Al hinges and brackets. FGM is deployed 2.25m from S/C center. SCM is deployed 1.4m from S/C center

THEMIS Instrument CDR 4 UCB, April 19-20, 2004 System Overview SCM Search Coil Magnetometer FGM Flux Gate Magnetometer FGM Base Hinge: Saloon Door Mechanism and Frangibolt Actuator SCM Frangibolt Tower FGM Elbow Hinge / Deploy Assist Device (DAD) SCM Base Hinge, similar to FGM Base Hinge, with no Frangibolt Carbon Fiber Tubes S/C Top Deck Saloon Door Spring Deployment Assist Spring Frangibolt

THEMIS Instrument CDR 5 UCB, April 19-20, 2004 System Overview 1) Frangibolts Fire 3) Mid-deployment 2) Elbow DAD Releases 4) Deployed

THEMIS Instrument CDR 6 UCB, April 19-20, 2004 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 Compliant. FGM Boom: 0.97kg Allocated. SCM Boom: 0.65kg Allocated. IN-9. No component of the Instrument Payload shall exceed the power allocated in THM-SYS-009 THEMIS System Power Budget.xls Compliant. Frangibolt: ~26W transient IN-13. The Instrument Payload shall survive the temperature ranges provided in the ICDs Compliant. IN-14. The Instrument Payload shall perform as designed within the temperature ranges provided in the ICDs Compliant. IN-16 The Instrument Payload shall comply with the Magnetics Cleanliness standard described in the THEMIS Magnetics Control Plan Compliant. THM-SYS-002 Magnetics Control Plan. IN-17 The Instrument Payload shall comply with the THEMIS Electrostatic Cleanliness Plan Compliant. THM-SYS-003 Electrostatic Cleanliness Plan IN-18 The Instrument Payload shall comply with the THEMIS Contamination Control Plan Compliant. THM-SYS-004 Contamination Control Plan Mission Requirements

THEMIS Instrument CDR 7 UCB, April 19-20, 2004 REQUIREMENTBOOM DESIGN IN-21. The Instrument Payload shall be compatible per the IDPU-Probe Bus ICD Compliant. THM-SYS-112 Probe-to-FGM Mag Boom ICD. THM-SYS-113 Probe-to-SCM Mag Boom ICD.. IN-23 The Instrument Payload shall verify performance requirements are met per the THEMIS Verification Plan and Environmental Test Spec. Compliant. THM-SYS-005 Verification Plan and Environmental Test Specification preliminary draft. 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 Compliant. THM-SYS-005 Verification Plan and Environmental Test Specification preliminary draft. Mission Requirements

THEMIS Instrument CDR 8 UCB, April 19-20, 2004 REQUIREMENTBOOM DESIGN IN.BOOM-1. Mag Boom deployment shall be repeatable to 1 degree Compliant. IN.BOOM-2. Mag Boom stability shall be better than 0.1 degree (includes bus and boom components) Compliant. IN.BOOM-3. Mag Boom deployed stiffness shall be greater than 0.75Hz Compliant. IN.BOOM-4. Mag Boom shall be designed to be deployed between 2 and 15 RPM about the Probe's positive Z axis. Compliant. IN.BOOM-8. The FGM boom shall be approximately 2 meters long. Compliant. IN.BOOM-9. The SCM boom shall be approximately 1 meters long. Compliant. IN.BOOM-12. All deployed booms shall include an inhibit to prevent inadvertent release. Compliant. Boom Requirements

THEMIS Instrument CDR 9 UCB, April 19-20, 2004 Mechanical Design - Status Major design changes since PDR Harness routed within mag booms. (Nov 03) Addition of 2 degree cant angle to FGM and SCM booms. (Nov 03) Change of FGM boom cant angle to 5 degrees, and SCM boom cant angle to 10 degrees, while minimizing stowed profile. (Jan 04) Modification of base hinge with flexures to reduce thermal strains. (Feb 04) Status Drawings completed and ETU sent out for bid for machining on 3/25/04.

THEMIS Instrument CDR 10 UCB, April 19-20, 2004 System Mechanical Design Frangibolt Specification Features: Lowest Mass & Power Reliable Frangibolt ® Actuator FC SR2 Bolt Strength2200N Mass20g Power25W Operating Temp.-65°C - +80°C

THEMIS Instrument CDR 11 UCB, April 19-20, 2004 System Mechanical Design Frangibolt Implementation V-Shaped Interface: Isolates the Frangibolt from vibration loads –vertical shear and moments Allows axial compliance for assembly Frangibolt Cover: Contains Frangibolt after firing –Shields components per NASA LLS 1360

THEMIS Instrument CDR 12 UCB, April 19-20, 2004 System Mechanical Design Elbow Latch Deployment Assist Spring Location Harness Tie- Down Clip Harness Routing Spool Hook-Pin Latch Device Flexure Feet Kickoff Disk Springs

THEMIS Instrument CDR 13 UCB, April 19-20, 2004 System Mechanical Design Base Hinge Design Features Deployment Assist Spring Frangibolt (Integrated Shear Support) Latch Pin Flexure Mount Feet “Saloon Door” Spring

THEMIS Instrument CDR 14 UCB, April 19-20, 2004 System Mechanical Design Base Hinge, Animated

THEMIS Instrument CDR 15 UCB, April 19-20, 2004 System Mechanical Design Boom Cant Effects Booms are “canted” out of the spin plane –Kinematically defined deployed configuration –Eliminate shadowing of solar panels –In the deployed configuration: –SCM cant of 10° –FGM cant of 5 ° –Deployment axis is also tilted out of plane FGM Base Hinge Deployed FGM Base Hinge Stowed

THEMIS Instrument CDR 16 UCB, April 19-20, 2004 System Mechanical Design Tube Lay-up [(±45) T300 / 0 M55J,4 ] s –T300 = high-strength carbon fiber/epoxy woven (0.005”/ply), M55J = high-modulus carbon fiber/epoxy tape (0.0025”/ply) Thickness = in. Inside diameter = in. Effective modulus = 31.3 x 10 6 psi (220 GPa) Mass per unit length = 3.2 g/in (1.26 g/cm)

THEMIS Instrument CDR 17 UCB, April 19-20, 2004 Dynamic Analysis Update Dynamic Model Overview Numerical solution of Kinematics & Rigid Body Dynamics Includes: –Kickoff spring forces –Deployment assist spring moments –Latching and de-latching events Updated for –Boom cant effects –Frictional torque

THEMIS Instrument CDR 18 UCB, April 19-20, 2004 Dynamic Analysis Update Assumptions: Increase in moment of inertia due to booms deploying will not slow the spacecraft enough to effect deployment  use a constant spacecraft spin rate to simplify analysis Linear springs Elastic collisions (conservative assumption) Constant frictional torques Booms are rigid links Deployment is in-plane

THEMIS Instrument CDR 19 UCB, April 19-20, 2004 Dynamic Analysis Update MATLAB Simulation Inputs –Satellite spin rates –Initial boom positions –Boom lengths, MOIs, spring constants, values of friction, etc… –Latching locations Outputs –Deployment animation –Hinge Forces and Moments –Deployment time

THEMIS Instrument CDR 20 UCB, April 19-20, 2004 Dynamic Analysis Update Boom Cant Effects Effects due to tilt of deployment axis –Strategy: Plug simulated 2-D values for α z and ω z (which also generates small values of α Y and ω Y into full 3-D moment equation, observe deviation from 2-D results –Error in predicted α z values ~0.12% –Addition of out-of-plane moments M X and M Y –These are nontrivial, producing frictional moments on the same order as sum of all other moments considered –Moments only act during high velocity or acceleration, i.e. during latching  positive effect –2-D Moment Equation: –Full 3-D Moment Equation

THEMIS Instrument CDR 21 UCB, April 19-20, 2004 Deployment Stress Analysis Stress/FEM Latching loads from dynamic analysis ALGOR Models for hinge analysis –FOS = rpm)

THEMIS Instrument CDR 22 UCB, April 19-20, 2004 Torque Margin Analysis Sources of friction considered Latch pin sliding along ramp : Vespel-3 on aluminum Clevis on hinge pin: 544 bronze on 303 stainless –Applies for base hinge and elbow –Forces due to 1) deployment spring force reacting through hinge and 2) out-of-plane moment due to boom canting

THEMIS Instrument CDR 23 UCB, April 19-20, 2004 Torque Margin Analysis

THEMIS Instrument CDR 24 UCB, April 19-20, 2004 Thermal Analysis Updates FGB Source:THEMIS Thermal Peer Review, 2/26/04

THEMIS Instrument CDR 25 UCB, April 19-20, 2004 Thermal Analysis Updates SCB Source:THEMIS Thermal Peer Review, 2/26/04

THEMIS Instrument CDR 26 UCB, April 19-20, 2004 Thermal Analysis Updates Tube bending with thermal gradient minimal effect (~.003° max)

THEMIS Instrument CDR 27 UCB, April 19-20, 2004 Vibration Analysis Update 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 Stowed frequency is dominated by tube. Deployed frequency is dominated by torsion spring stiffness at base hinge 1 st mode shape of stowed FGM outer boom. 1 st mode resonance StowedFGM inner tube163 Hz FGM outer tube152 Hz SCM tube139 Hz DeployedFGM tube4.8 Hz SCM tube3.7 Hz

THEMIS Instrument CDR 28 UCB, April 19-20, 2004 Design Margins Failure ModeMin. FOSLocation FPFF During Elbow, 20RPM, u=0 Yielding During 20RPM, u=0 FPFF, Launch support ring, 100g Torque 2RPM4Base Hinge, End of Travel, u=0.6 Stowed Natural Frequencies1.34SCM Deployed Natural Frequencies4.8FGM Mass Margin16g underSCM Deployment Temperature Margins-50°C to 55°CEstablished by testing

THEMIS Instrument CDR 29 UCB, April 19-20, 2004 Mass & Power Mass Power 25W transient for Frangibolt deployment.

THEMIS Instrument CDR 30 UCB, April 19-20, 2004 Fabrication and Assembly Documentation All fabrication and assembly processes are developed and documented as Manufacturing Process Instructions. Any fabrication work and assembly will be logged. Fabrication Boom tubes – In-house Hinges – external machine shops. Assembly Bonding boom tubes and end fittings. Assembling hinges, harness and Frangibolt.

THEMIS Instrument CDR 31 UCB, April 19-20, 2004 Composite Boom Fabrication In-house capability to manufacture composite tubes using the table rolling process. Bldg 151,Richmond Field Station (RFS). In service since March Prototype boom tubes successfully fabricated. Table RollerShrink Tape WrapperOvenMandrel Puller

THEMIS Instrument CDR 32 UCB, April 19-20, 2004 Integration Plan Integration of Tube and End Fittings End fittings will be bonded to the boom tube via bonding fixtures. Bonding fixture controls component length and clocking between end fittings. Bldg 151, RFS.

THEMIS Instrument CDR 33 UCB, April 19-20, 2004 Assembly Plan Assembly of hinges Assemble base hinge, and DAD boxes. Do not assemble elbow hinge can assembled. Integration of harness Harness, without connectors, will be threaded through booms before assembling of boom. For the FGM, harness must also be threaded through the elbow before it is assembled. Assembly of mag boom Assemble hinges and tubes with end fittings. Integration of Frangibolts Frangibolts will be installed after boom is assembled.

THEMIS Instrument CDR 34 UCB, April 19-20, 2004 Test Plan Pre ETU testing Tube vibration Mechanical Characterization of laminate Proof testing of bonded joints. Pre Instrument Assembly testing Component hinge deployment testing (ambient and thermal vacuum) Composite tube proof testing. Spring rate testing Assembled Instrument testing Deployment, Vibration, Thermal ETU units will be tested with mass mockups.

THEMIS Instrument CDR 35 UCB, April 19-20, 2004 Pre ETU Testing Boom Vibration Adjustable mounting on the shaker to test different support lengths for FGM and SCM booms. Test will take place at Wyle Laboratories, Santa Clara 0.25g sweep from 5 Hz to 2000 Hz

THEMIS Instrument CDR 36 UCB, April 19-20, 2004 Pre ETU Testing Mechanical Characterization of laminate A laminate will be constructed and a coupon used for stiffness and strength. Four point bending test. Proof testing of bonded joints. An end fitting will be bonded to short lengths of the magboom and thermal cycled to THEMIS requirements. A tensile proof test of the bonded joint is carried out after thermal cycling.

THEMIS Instrument CDR 37 UCB, April 19-20, 2004 Pre Instrument Assembly Testing Hinge Deployment testing Functional testing Test after thermal vacuum test. Spring rate testing Springs as delivered by vendor will be tested. Composite boom with end fittings Tensile proof test after thermal cycling.

THEMIS Instrument CDR 38 UCB, April 19-20, 2004 Deployment Test Plan Ambient Testing Spinless Horizontal Deployment –Gravity off-load fixture using air bearings –Conservative test for torque margin due to lack of spin Vertical Gravity-Assisted Deployment –Gravity used to simulate centrifugal force at end of stroke –Conservative test for latch up load due to large force at end of stroke Non-Ambient Testing Thermal vacuum test for hinge operation Horizontal deployment at -50°C to 55°C

THEMIS Instrument CDR 39 UCB, April 19-20, 2004 Deployment Test Plan Instrumentation Encoders at joints Accelerometers at link CGs Data capture via NI DAQ and LabVIEW

THEMIS Instrument CDR 40 UCB, April 19-20, 2004 Test Plan Vibration Test Plan Assembled boom will be tested at Wyle Laboratories, Santa Clara 0.25g sweep from 5 Hz to 2000 Hz. Thermal Testing

THEMIS Instrument CDR 41 UCB, April 19-20, 2004 Performance Assurance Procedures During personnel, all assembly must follow established Manufacturing Process Instructions. Work performed on each assembly will be logged. Documentation Manufacturing Process Instructions for –Tube fabrication –Bonding of hinge and tubes –Assembly of hinge, and harness –Installation of frangibolts

THEMIS Instrument CDR 42 UCB, April 19-20, 2004 Schedule ETU Assembly 5/14/04 Testing 5/19/04 FLT Tubes 6/2/04 Hinges 8/4/04 Assembly After assembly, deployment test (4 days), vibration test (1 day), and thermal test (5 days)

THEMIS Instrument CDR 43 UCB, April 19-20, 2004 Parts and Materials Requirements Materials Outgassing: 1% TML, 0.1% VCML Magnetic cleanliness ComponentMaterial% Total Mass Boom TubesCarbon fiber/cyanate ester: M55J/RS3, T300/RS3 28.9% HingesAl 6061-T6 3XX stainless steel Bronze 46.1% 7.8% 4.8% SpringsBeCu 8.3% FastenersStainless Steel 1.1% Instrument FastenersTi AdhesiveHysol 9394 GSEAl 6061-T6

THEMIS Instrument CDR 44 UCB, April 19-20, 2004 Contamination Control Magnetic cleanliness Comply with Magnetics Cleanliness standard described in the THEMIS Magnetics Control Plan Use of non-magnetic materials e.g. Al, carbon-fiber for mag boom. Minimize tools made with magnetic materials. Electrostatic cleanliness Comply with THEMIS Electrostatic Cleanliness Plan Keep exposed surfaces of the mag boom conductive by minimizing exposed hard anodizing, exposing outer layers by grinding down epoxy.

THEMIS Instrument CDR 45 UCB, April 19-20, 2004 Problem Areas Schedule Design was changed. ETU testing was delayed.