1. 3-4 Sept. 2008EFW INST+SOC PDR141 Electric Field and Waves (EFW) Spin Plane Boom (SPB) Gregory Dalton Space Sciences Laboratory University of California – Berkeley gdalton@ssl.berkeley.edu EFW Spin Plane Boom

2. 3-4 Sept. 2008EFW INST+SOC PDR142 Overview Design Requirements/Drivers Design Overview Theory of Operation Flight Heritage Custom Design for RBSP Analysis and Testing Overview

3. 3-4 Sept. 2008EFW INST+SOC PDR143 Design Requirements/Drivers Thermal Interface Survival: -45 to +60°C Deployment: -20 to +40°C Preamp survival: -160 to 80°C Preamp science range: -55 to +70°C Mass NTE 2.42 kg Currently 1.943 kg with Mounting Feet Design Deploy Sensor to 80/100m Tip-to-Tip with 4.7cm resolution Test/Enable Plug accessible on S/C Mount at 10° angle to S/C Panel 7 Conductor Cable to Preamp Preamp Enclosure designed for ease of assembly Keyreel designed to unfurl Fine Wire at 10m & 15 RPM

4. 3-4 Sept. 2008EFW INST+SOC PDR144 Design Overview – Overall Dims [cm] inch SPHERE PREAMPLIFIER ENCLOSURE COMPOSITE CABLE FINE WIRE

5. 3-4 Sept. 2008EFW INST+SOC PDR145 Design Overview - External ENABLE PLUG/ TEST CONNECTION MOUNTING FOOT SPOOL CONNECTION S/C PANEL

6. 3-4 Sept. 2008EFW INST+SOC PDR146 Design Overview - Internal SPHERE CONTACT DOOR OPEN SWITCH RELEASE PIN DOOR RELEASE RING PIN PULLER METERING WHEEL DEPLOY MOTOR SCIENCE/ENG CONNECTORS END OF WIRE SWITCH SPOOL BRAKE CABLE CONNECTOR COMPOSITE CABLE SLIPRING SPOOL SECTION MOTOR SECTION MAGNETIC/ EMI SHIELD BEVEL GEARS CAM METERING WHEEL

7. 3-4 Sept. 2008EFW INST+SOC PDR147 Design Overview – Preamp Enclosure STRAIN RELIEF TANTALUM SHIELD SCREW FITTING PWB USHER FERRULE CABLE HOLDER GUARD PREAMPLIFIER SPRING CONTACT PWB ASSEMBLY

8. 3-4 Sept. 2008EFW INST+SOC PDR148 Theory of Operation Integration and Launch Stowed and Unpowered Composite Cable on Spool, held by Brake Sphere and Preamp caged by Doors Doors held closed by Release Pins

9. 3-4 Sept. 2008EFW INST+SOC PDR149 Theory of Operation Deployment Release Ring rotates when Pin Puller Actuated Release pins move clear of Doors Doors open, indicated Motor pulls cable off Spool at ~2cm/s and meters Cable every 4.7cm At 10m and 15RPM, Fine Wire Unfurls End of Travel switch disables motor power

10. 3-4 Sept. 2008EFW INST+SOC PDR150 Flight Heritage 25+ years mature Radial Boom design at SSL Mature Design/Vendor Familiarity Previous mission reviews and test data Critical components from proven vendors Test fixtures and procedures Original Dr. Pankow SPB design

11. 3-4 Sept. 2008EFW INST+SOC PDR151 Custom Use for RBSP Gore Cable 100m Tip to Tip (~49m per boom) No coax Kapton vs. PTFE insulation Simplified Release Mechanism Pin Puller Secures own Power Redundant Packaged for RBSP Completely enclosed Panel Mount Electronics Modified Harness Door Open Indication RBSP Composite Cable

12. 3-4 Sept. 2008EFW INST+SOC PDR152 Analysis - Damping CableDamping (J/rad^2) CRRES-0.031 RBSP ETU-0.0153 Energy Dissipated per cycle per boom: Cable Damping Test Simple Pendulum test Tip Mass Simulates Cable Load Future test to include accurate RBSP tip mass and vacuum environment

13. 3-4 Sept. 2008EFW INST+SOC PDR153 Analysis - CTE Coefficient of Thermal Expansion Design for low CTE Test from 20 – 80°C 12ppm/°C from RBSP prototype

14. 3-4 Sept. 2008EFW INST+SOC PDR154 Setpoints and Margins Fine Wire: 0.009”ø, 7x7 strands, stress relieved stainless steel Construction > 50N breaking strength, tested with end conditions > 10:1 pulley to cable diameter ratio, de-rate cable strength to 85% -> 42N Predicted load during deployment: 6N Composite Cable: 3200 Denier Kevlar 49 strength member, 600N breaking strength Spool pullout force: 13N EOT motor power cutout: 45N Shear Pin: 135N Predicted load during deployment: 8N Motor Assembly: Bevel gear DF: >50 Motor manufacturer DF: 4x Continuous torque: 2120mNm (x2 after Bevel gears) Max intermittent: 4240mNm (x2 after Bevel gears) Torque to break shear pin: 4050mNm SPB Structure First Mode – 300hz

15. 3-4 Sept. 2008EFW INST+SOC PDR155 Testing Prior to Environments: Motor burn-in, startup and running current tests Pin Puller power profile Margin Checks –Torque: Door springs, motor torque –Force: Spool pullout, EOT switch, door release, fine wire and composite cable proof loads Fine Wire force/deflection characterization Electrical Isolation Mass Properties Functional deploy – Self Shock Length Calibration THEMIS: 18 Month Motor Accelerated Life Test

16. 3-4 Sept. 2008EFW INST+SOC PDR156 Testing Vibration per APL Environmental Test Spec New Fixtures for RBSP S/C Mounting – Force Limiting Unpowered Testing ETU to Qualification Levels, Flight to Acceptance Levels

17. 3-4 Sept. 2008EFW INST+SOC PDR157 Testing Thermal Vacuum Survival Temp: -30 to +60°C Full Deployment Test: -25 to +55°C Modified Test Fixtures for RBSP –Protect Sphere surfaces –Lower Keyreel spring force –Mounting scheme

18. 3-4 Sept. 2008EFW INST+SOC PDR158 Backup Slides Long Lead Items: Gore Cable –Samples in the Mail –CTE/Damping/Strength Tests –November Delivery Globe Motors –Order Placed –20 wks TiNi Pin Pullers –PO being processed –12 wks Sliprings –12 wks Ongoing Developments: Verify Composite Cable Production Design Mounting Foot Analysis

19. 3-4 Sept. 2008EFW INST+SOC PDR159 Backup Slides Standard UCB Construction Machined Parts –6061T6 Aluminum –544 Bronze –Stainless Steel –Titanium –Delrin, PEEK, Vespel –Vulcanized Elastomer –Tantalum Finshes –Alodine –Anodized –DAG-213 –Gold Plating Thermal Treatments No Special Manufacturing Techniques

20. 3-4 Sept. 2008EFW INST+SOC PDR160 This page intentionally almost blank