THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 1 UCB, April EFI Radial Boom (SPB Spin Plane Boom) Bill Donakowski Mechanical Engineer Space Sciences Lab University of California Berkeley Picture to be updated

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 2 UCB, April Requirements (1/2) Structure, Testing, Materials Mechanical-Verification-Spec-1c (Swales/THEMIS specific) THEMIS PAIP GEVS A/R (GSFC General Environmental Verification Specification) Thermal Near Exterior Solar Panel, device gets cold Operational: -20 C to +40 C Range for Deploy: -20 to +45 C Magnetic Cleanliness Electrically Isolated Sensor Surfaces and Wires Mass <1881 grams Functionality Maintain Spool, Coaxial Wire, Preamp, Sphere during Launch Open External Release Door at IOC Pay out Cable, Preamp, Sphere via Inertia of Spinning SC and Gearmotor/Metering Wheel Assy to full length Maintain Pivot Point following Deploy

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 3 UCB, April Requirements (2/2) Monitoring and Safeguards Turns Counter counts number of rotations of metering wheel to monitor deploying wire length (resolution of +/- 5 mm) Tension Monitor shuts off Motor if wire gets taut, either obstructed or at end of deploy Deployed Wire Lengths One Pair: 40m Tip-To-Tip Other Pair: 50m Tip-To-Tip Fine Wire: 3m Wire Length packed in all units to be for 50m Configuration –All SPB Units Completely Interchangeable with Any Other –Masses of Units Balance on Probe Test Port Connector On External Face of SPB Accessible following integration onto Probe Allows testing of Continuity from IDPU and General Aliveness

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 4 UCB, April Flight Heritage Radial Boom Design goes back 25+ years Polar Cluster FAST Mature Designs/Vendor Familiarity Many Design Reviews and Test Data from prior Programs Critical Component Vendors for THEMIS (Wire) Test Fixtures and Procedures in-house at SSL Personnel hired to Develop and Build Flight Units –Greg Dalton (Mechanical Engineer) –Stephan Martin (Mechanical Technician) Dr. Pankow to remain as advisor to program

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 5 UCB, April Materials and Construction Standard UCB Construction Most Components Machined Aluminum –6061 T6 and 7075 T73 –Alodined and Anodized Machined Plastics –PEEK Machined Magnesium Alloy AZ31B –Chosen for Weight Relief in Structure –Not MSFC-SPEC-522 High Resistance to SCC –Table II ‘Moderate Resistance’ –Requires MUA for use Thermal Treatments Exterior of SPB internal to Probe is MLI Blanketed External of SPB External to Probe is ITO Coated Silver Teflon Applied Locally No Heaters Required at this time Common manufacturing techniques used No Difficult Fabrications

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 6 UCB, April Design Changes from PDR (1/2) Gearmotor Brushed Design Changed from Brushless Baseline Brushless Motors rejected due to Mass and Schedule –Individual Motors 50g Heavier –Required Drive Electronics in Box added 125g –Lead Times approx 10 weeks longer than Brushed –Brushed Motors is Heritage Design Instrument Height Decreased by.6” to match Probe CG Easily accommodated in existing design Decrease in Height moved SPB away from Probe Tanks 90/90/90/90 Configuration of SPBs Easily Accommodated Door Release Mechanism Design Complete Use of SMA (Shape Memory Alloy) Wires to Release Spring Loaded Latch Mass Mass Decreased based on Noted Changes Wire Lengths FINALIZED (40m and 50m Tip-To-Tip) Coaxial Wire Lengths to be in Pairs of 16.5m and 21.2m

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 7 UCB, April Design Changes from PDR (2/2) Added Sphere Monitor Conductive Finger Touching Sphere in Cone Check of Continuity Read Back to Enable Plug Moved Main Connector Cable to IDPU Accommodate Swales Cabling Design

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 8 UCB, April Design Overview 4 x Attach Legs with Ultem Spacers for Thermal Isolation Gearmotor With Bevel Gears Meter Wheel Base (Magnesium) Sphere and Preamp Release Doors Main Wire Spool Release Tube Connector (Cable to IDPU)

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 9 UCB, April Design Overview

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 10 UCB, April Design Overview 4 x Attach Legs with Ultem Spacers for Thermal Isolation Meter Wheel Base (Magnesium) Release Doors (Spring Preloaded) Main Wire Spool Release Tube Preamp

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 11 UCB, April Theory of Operation Integration and Launch Stowed and Unpowered Wire Wound about Spool, constrained by pinch wheels Release Doors Closed Sphere/Pre-Amp Constrained by Release Doors Deployment Release Doors Opened via SMA Wire Release Mechanism Spin of S/C puts outward force on Sphere and Preamp Motor Acts as brake to prevent motion; coaxial wire in tension Motor powers rotation of Meter Wheel Sphere and Preamp is payed out Release Doors Close Back Around Wire (via torsion springs) As Centrifugal Force exceeds 2G at Sphere, Sphere Key Reel Spring force is overcome and Sphere moves away from Preamp Monitoring –Limit Switch on Shaft counting Rotations –Tension Sensor to sense High Tensile Force Science Ops Deployed Booms Configuration Unchanged

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 12 UCB, April Theory of Operation Meter Wheel Preamp MotorMain Wire Spool Pinch Rollers Release Doors Sphere Green-Tag Enable Plug Sphere Contact Monitor

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 13 UCB, April Release Mechanism Release Wheel Rollers mounted on Wheel holds Release Rods Rotation of Release Wheel via SMA wires Removes preload from Release Rod Release Rod Preloads Door w/ Springs Extends to allow Doors to Open at Release of Springs Limit Switch Assy

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 14 UCB, April Electrical Schematic

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 15 UCB, April Mass and Power Mass Current Mass 1,617g –Phase A Baseline: 1,881g –At PDR: 1,757g Mass Decreasers –Change to Brushed Motors –New hardware aggressively weight-relieved Mass Increasers –Wire Length Increased from 18m to 20m –Wire Density: 9.8 g/m Power (per Unit) Door Release Operation (SMA: 2 secs Max) –10 W Boom Deployment (Gearmotor Activation) –3.4 W

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 16 UCB, April Key Stress/Force/Torque Analysis Summary Bevel Gear Tooth Stresses Assuming Worst Case of All Cable Loading on 1 Tooth of Gear –Lowest Margin on Aluminum Gear –Margin: >50 Release Mechanism Margin Force Required to Open Release Door: 1.74 Lbs Force Supplied by SMA Wires on Release Wheel: 8 Lbs Force Ratio: 4.6 (GEVS Requirement: 3.0) Torque Margin On Metering Wheel Torque Required to Pull Wire on Metering Wheel: 12 in-Lbs Torque Supplied by Gearmotor to Metering Wheel: 43.7 in- Lbs Torque Ratio: 3.6 (GEVS Requirement: 3.0)

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 17 UCB, April FEM Modal Analysis Preliminary Modal Analysis Performed Algor Software –Preliminary Analysis –Further Analysis Required First Mode Twisting About Z Axis Frequency: 450 Hz

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 18 UCB, April Testing Testing Completed Pull-Testing of Coaxial Wire –Used for Selection of Flight Wire –Sample Pull Testing of Supplied Flight Wire Functionals during build-up –Motor Turn-on; SMA Actuations Testing Planned on EM in short term Vibration Test to Qual Levels –Late April 2004 Thermal Vacuum –Following Vibe and Completion of TV Chamber –Approx. mid-May 2004 Functional Deploys –Early May 2004

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 19 UCB, April Red Tag/Green Tag Items Red Tag Release Door Cover One per SPB Safety Item to Prevent Release of Door On Exterior of Probe; Easily Removable Late in Flow Green Tag Enable Plug Cover on Enable/Test Connector Easily Installed Late in Flow

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 20 UCB, April Schedule ETU (Engineering Test Unit) Assy Completed Only Problem: Wire Fabrication Functional Testing Begun (Motors, Door Release) Vibration Testing Schedule for 15 April 2004 Flight Procurements Machined Parts Ready for RFQ All Long Lead Items on Order Flight Assembly Scheduled to Start mid-May Tracking against Schedule Currently approximately 2 weeks Behind –Wire Fab Issues –‘Normal’ Problems Associated with First Build of Engineering Model –Facilities Lagging by 3-5 weeks

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 21 UCB, April Long Lead Hardware Multi-Conductor Wire Vendor: Gore Custom to UCB Spec (THM-SPB-M101) 8 single conductors/ 1 coax 100% of Flight Wire Received Spares: 50% Over DC Brushless Gearmotor Vendor: Globe Motors 5 Flight Motors Received Remaining Flight Units Due May 2004 Barden Bearings Flight Units On Order, most units in-house Slip Ring 10 Weeks ARO Flight Order Placed late March 2004

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 22 UCB, April Issues and Concerns Busy Summer/Fall Flight Units to Be Assembled and Environmentally Tested Thermal Vacuum Facilities Ramping up Slowly Learning Curve on New Wire/Procedures/Personnel

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 23 UCB, April Facilities Assembly Room 165 SSL Room Complete and in-house for EM Build-Up Instrument Integration Facility Room 20 SSL Largest Clean Room at SSL Functional though Serving as ‘SSL Museum of Flight’ (Storage of Remnants of Old Projects) Clean-Up and refurbishment to be completed June 2004 Vibration Testing Facilities Primary Test Facilities Identified (Wyle Labs, Quanta Labs) Back-Up: NASA Ames Spectrums and Test Protocol very standard UCB has used all three Facilities; all are functional and lightly subscribed over the next 12 months Testing of Multiple Instruments at one time to be implemented

THEMIS Instrument CDR Bill Donakowski/ EFI Radial Boom 24 UCB, April Facilities Thermal Vacuum Tanks SSL High Bay Chamber –Completed and Ready to Use –Competing for use with STEREO SSL Small Tank, Room 20 –Vacuum System Functional –New Thermal System to be Installed May 2004 –Should be functional end of May 2004 SSL Large Tank, Room 20 –Vacuum System Functional –New Thermal Control System being Designed –Goal of Start-Up: July 2004 SSL New ‘Roll-Around’ Chamber –Order Placed with Vendor –Due Date: early June 2004