Radiation Belt Storm Probes RBSP Axial Booms Jeremy

Radiation Belt Storm Probes RBSP Axial Booms Jeremy Mc. Cauley Aerospace Engineer Space Sciences Laboratory, UCB jeremymc@ssl. berkeley. edu RBSP/EFW CDR 2009 9/30 -10/1 465

Axial Booms (AXB) Jeremy Mc. Cauley Aerospace Engineer Space Sciences Laboratory, UCB jeremymc@ssl. berkeley. edu Spacecraft +Z AXB Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 466

EFW AXB Overall Flow Design PDR ETU Build ETU Test Peer Review July 28 Flight DWG Release • PDR • RFAs: 6 AXB related, 6 Closed • Peer Review • AIs: 4 AXB related, 4 implemented • Suggestions: 11 AXB related, 11 implemented CDR • CDR Flight Build • RFAs: 0 (? ) Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 467

EFW AXB Overview • Design Drivers • Design Description – – Concept Heritage Assembly Breakout Thermal • ETU Integration and Testing (I&T) • Changes Since ETU Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 468

EFW AXB Design Drivers • Deploy spherical electric fields probes up to 7 meters from center of spacecraft with an E-Field sensor and preamp at the end. • Length adjustable (longer only) on orbit with a resolution of +/- 0. 5 cm • Interface to spacecraft to support deployable booms. • Meet straightness requirement (< 1° from spin axis). • Provide relief for CTE mismatch between Gr/E Tube and SC body. • Provide a connector for test input to the sensor accessible during all integration phases. • Total Mass not to exceed 8. 57 kg (Each AXB Unit to not exceed 3. 64 kg; AXB Tube to not exceed 1. 29 kg) • Interface Operational Temperature Range: -25 to +55 C (TBR) • Interface Survival Temperature Range: -30 to +60 C (TBR) Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 469

EFW AXB Concept Upper Boom Unit (+Z) Lower Boom Unit (-Z) • Axial Boom Unit (AXB) – Sensors Extended from SC on Stacers • Compact for Launch • Rigid after Deploy • Adjustable Length Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 470

EFW AXB Heritage • Heritage Unit – Primarily AXB from THEMIS, modified for length and to fit RBSP SC • Including Tube, Structure, Stacer, DAD design and springs • Similar to units on STEREO (6), THEMIS (10), POLAR and FAST – More than 60 years of on orbit operation – Whip from Rockets • replaces THEMIS Whip Stacer – Direct Drive Unit from THEMIS SPB • Added Refinements – Direct Drive Unit on a Stacer – DAD Lock Wheel Assemblies – Sphere Caging Mechanism Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 471

EFW AXB Order of Deploy Stowed Unit • Unpowered • Fully Restrained Step 1: Whip Deploy • Frangibolt Actuated • Spring Powered +Z SC Axis Step 2: Stacer Deploy • Frangibolt Release • Motor Driven (3 cm/s) • Length Adjustable • Fault Analysis in Backup Slides Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 472

EFW AXB Design Description: AXB Upper Boom Unit (+Z) Lower Boom Unit (-Z) Dimensional Scale • Structural Design Tube – End Supported Tube with Aluminum End Fittings Diameter – Two (2) Identical Boom Units Deck • Stationary Deploy Assembly Separation • Moving DAD Whip • Stacer Length • Whip and Spherical Electric Fields Probe Sphere Diameter Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 6” [15 cm] 43. 5” [108 cm] 13” [33 cm] 3. 2” [8. 0 cm] 473

EFW AXB Tube Assembly • Structural Design – End Supported Tube: Graphite Epoxy, M 55 (Layup: -60/60/0/0/60/-60 [quasiisotropic]) – Fixed-Fixed First Frequency: 257 Hz – Tube Static Stress Margin: 10 Flexure Tube – End Fittings: Al 6061 -T 6 – Lower Support includes a drumhead flexure design • Currently 89. 1 lbf @ 52ºC d. T – Joint Epoxy: Hysol 9309 NA – Bond Shear Stress Margin: 30. 3 Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 End Fitting Flexure at d. T=52ºC 474

EFW AXB Tube Testing • Structural Testing – Thermal cycling – Static loads – Structural loads testing • Integrated to SC Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 475

EFW AXB Design Description: Booms Stowed Configuration • Boom Design – Stationary Deploy Assy Whip – Moving DAD – Stacer – Whip and Spherical Electric Fields Probe Deploy Assy DAD Stacer Deployed Configuration Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 476

EFW AXB Design Description: Booms Stowed Configuration • Stationary Deploy Assy – Sphere Caging Mechanism – Direct Drive Assembly – Roller Nozzle #1 Sphere Caging Mechanism Direct Drive Assy Roller Nozzle #1 Deployed Configuration Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 477

EFW AXB Design Description: Cage • Sphere Caging Mechanism Stowed Configuration – Protect Spherical Electric Field Probe – Release Whip on Orbit • Frangibolt Actuator (Next Slide) • Top Opens • Cam Releases Arm • DAD Plunger with Kickoff Spring Starts Whip DAD Plungers – AC Test Contact for Ground Operations Frangibolt – Torque Margin: 40. 9 • Spring to Friction Drag – Green Tag Enable Plug/ Ground AC Test Contact Test Plug Enable Plug Deployed Configuration Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 478

EFW AXB Design Description: Frangibolt • Ti. Ni Frangibolt – 500 lb Retention Force • For Launch Loads Only • Static Margin: 14 – Resettable – 25 W @ 28 Vdc – 95°C Actuation Temperature – Trending Data Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 479

EFW AXB Design Description: Direct Drive Frangibolt Slip Ring Motor Sense Switches • Direct Drive Assembly Spool Harness – – Stacer Frangibolt Release Harness Spool: Max Capacity 6. 66 meters 0. 068” diameter cable Motor Drive Mechanism: Globe A 1430 Motor (1000: 1 gear ratio) Sense Switches: Stacer Release, End of Wire and Turn Counter (Newark, 1 HM 19) – Slip Ring (Airflyte CAY-1398) – Length Resolution: 0. 65 cm/click BOT, 0. 52 cm/click EOT, 5. 2 clicks/s – Torque Margin: 7. 6 (Motor Torque to Retract Stacer) Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 480

EFW AXB Cable Load Path Glue Joint Tie Off Point • Cable Force Path – Force is carried completely in Kevlar overwrap – Static Margin: >100 Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 481

EFW AXB Design Description: Nozzle • Roller Nozzle #1 – Centering of the Stacer – Resist SC Forces • Springs designed to 1. 6 lb minimum radial force Rollers Rocker Arms Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 482

EFW AXB Design Description: DAD • Moving DAD – Deployment Assist Device (DAD) with Kickoff Springs – Lock Wheel Assemblies • Increase Unseat Force from 6 lbs to 15 lbs axial from 1. 6 to 4. 5 lbs radial Roller Nozzle #2 DAD Springs Lock Wheel Assy – Roller Nozzle #2 • Springs designed to 1. 6 lb minimum radial force – Force Margin: 2. 1 • DAD Springs to Friction Stowed Configuration Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 Deployed Configuration 483

EFW AXB Design Description: Stacer • Stacer – Helical Spring – Deployed Acts as a Rigid Tube • Spin Adjusted Resonance: 26. 5 RPM – Force Margin: > 3 Deployed Configuration • Stacer Force to Friction MAIN STACER PROPERTIES Stacer Mc. Cauley [in] [mm] STRIP THICKNESS 0. 004 0. 10 STRIP WIDTH 5. 000 127. 00 TIP DIAMETER 0. 700 17. 78 BASE DIAMETER 1. 128 28. 65 EQUIVALENT DIAMETER 1. 005 25. 54 RBSP/EFW CDR 2009 9/30 -10/1 484

EFW AXB Design Description: Whip • Whip and Spherical Electric Fields Probe – Hinge • Torque Margin: 3. 6 • Hinge Spring to Friction • DAG 213 Coated – Whip Tube • FOS (Bending on Deploy): 2. 0 • DAG 213 Coated – Sphere • Probe and Preamp Assy • DAG 213 Coated Stowed Configuration Sphere Internal View Preamp – Cannot Clean DAG 213 surfaces – All Three Isolated for Potential Control – Fundamental Frequency: 23. 0 RPM • (> 4 x SC Spin Rate Rigid) Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 Hinge Whip Sphere Deployed Configuration 485

EFW AXB Design Description: Stress Margins Critical Part Mc. Cauley Stress Margin Stacer Frangibolt 14 Mounting Flexure 0. 9 Mounting Flange 2. 7 Mounting Tube 10 Tube Bond (Top) 30 Whip Tube 128 Whip Hinge Pin 34 RBSP/EFW CDR 2009 9/30 -10/1 486

EFW AXB Glue Bond Margins Epoxy: Hysol 9309 NA Lap Shear Strength (psi): 4000 Joint Area (in^2) Strength (lbs) * Force (lbs) Margin Whip to Sphere 0. 244 155 0. 051 3010 Whip to Hinge 0. 196 124 0. 051 2418 DAD Rod to DAD Tip Tube to Tip End 0. 349 1. 077 221 683 2. 17 3. 17 101 214 Tip to Tip Tube 1. 077 683 3. 17 214 Tip to Safety Pin 1. 127 715 3. 17 224 * Joint Strength is derated according to surface preparation requirements as discussed in HTN-102050 -017, dated 06/15/2000, as received from Chris Smith, UCB/SSL. Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 487

EFW AXB Glue Bond Margins Whip to Hinge DAD Rod to DAD Tip Whip to Sphere Tip Tube to Tip End Tip to Tip Tube Tip to Safety Pin Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 488

EFW AXB Design Spreadsheets • • • • Caging Spring Torque DAD Lock Spring DAD Telescoping Spring Deploy Motor Frangibolt Firing Times Hinge CTE Hinge Spring Torques Large Fine Pitch Bolt Torques Mass Properties Roller Nozzle Spring Sense Line Resistances Tube CTE Whip Torsion Spring Wire and Spool Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 489

EFW AXB Thermal • • Thermally Coupled to the SC Spherical Electric Fields Probe, Whip and Hinge: – Coated with DAG 213 Stacer: – Mill Finish Elgiloy Moving DAD: – Alodine (1500, Clear, 300 s immersion) – Electroless Nickel Plating with Teflon Impregnate Stationary Deploy Assy: – Alodine (1500, Clear, 300 s immersion) – Electroless Nickel Plating with Teflon Impregnate End Supported Tube – M 55 Graphite Epoxy Aluminum End Fittings – Alodine (1500, Clear, 300 s immersion) Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 490

EFW AXB Long Lead Items • Frangibolts – Ordered: August 2009 – ~10 week lead • Gore Cable – In House • Motor – In House • Stacer – In House Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 491

EFW AXB Order of Assembly Preamp Mech Assembly Test Preamp PWB Assembl e Whip Paint: Whip, Stacer and Sphere Assembl e Stacer Assemble Doors Motor Burn In Harness Motor Harness SW 1 Assemble Caging Mech Assemble Sphere, Whip and Preamp Whip and Cage Electrical Functional Assemble Stacer Assembly Assemble DAD Assemble Direct Drive (-500) Assemble Stacer Mechanism Harness Assembly Stacer Mech Functional, Length & Runout Measurement, Continuity Check Harness Diode Block Mc. Cauley Integrate Whip and Cage RBSP/EFW CDR 2009 9/30 -10/1 Whip and Cage Mechanical Functional PER 492

EFW AXB I&T: Environmental Test Matrix RBSP EFW ENVIRONMENTAL TEST MATRIX Mc. Cauley T ESC AND GROUNDING DC MAGNETICS BAKEOUT THERMAL BALANCE CONDUCTED SUSCEPTIBILITY THERMAL VACUUM (# CYCLES) CONDUCTED EMISSIONS SELF COMPATIBILITY TURN ON/OFF TRANSIENTS ESD DISCHARGE TEST BONDING AND ISOLATION RADIATED SUSCEPTIBILITY EMFISIS INTERFACE TEST RADIATED EMISSIONS INTERFACE VERIFICATION FAILURE FREE HOURS T 2 T 1 T T 100 T 9 T A, T A 2 M 1 T 12 T 6 T 7 T 7 T 2, T 16 5 7 T T T T 11 M 2 T 9 T 13 T 12 5 T 12 T 14 T 6 T T T T 14 7 5 T T A 2 M M 3 RBSP/EFW CDR 2009 9/30 -10/1 M 2 T 10 T T DEEP DIELECTRIC DISCHARGE A 1 T A 1 T A RADIATION T 4 T 1 T UCB UCB UCB 4 4 2 2 2 2 M 2 T 3 3 A 1 T T 1 T 7 4 UCB T 7 T 1 T 7 A 1, T 4 T 5 OTHER T 1 MECH Fn - DEPLOY MASS PROPERTIES T 6 CONTAM. VENTING/PRESS. PROFILE UCB UCB T 12 THERMAL CLAMP BAND SHOCK PROOF TEST M 1 2 8 8 4 4 UCB T 15 ACOUSTIC SINE VIBRATION RANDOM VIBRATION T 1 ELECTRICAL A 1, T 4 1 UCB T 14 T 1 Instrument EFI SPB Pre-amp EFI AXB Deploy Mech AXB less whip (*) AXB Pre-amp AXB Cage/whip Tube IDPU Instrument Harness Instrument on S/C STATIC LOAD ETU SUPPLIER COMPONENT (ITEM) QUANTITY MODAL SURVEY MECHANICAL ALIGNMENT HARDWARE 493

EFW AXB Environmental Testing PER Integrate Stacer, Whip and Cage Mechanical Functional Whip and Cage TV Hot Deploy Stacer Mech TV Hot Deploy, Length & Runout Measurement, Continuity Check Mc. Cauley Electrical Functional Test Integrated Vibration Test Dis-Integrate Stacer, Whip and Cage Electrical Functional Test Stacer Mech Functional, Length & Runout Measurement, Continuity Check Whip and Cage TV Cold Deploy Stacer Mech TV Hot Deploy, Length & Runout Measurement, Continuity Check Integrate Stacer, Whip and Cage RBSP/EFW CDR 2009 9/30 -10/1 Mass Properties Science Calibration PSR 494

EFW AXB I&T: Deployments • Functional Deployments – Expected number of deployments on the instrument at launch: 4 • Functional • Post Vibe Functional (“test as you fly” exception) • Thermal Vacuum Hot • Thermal Vacuum Cold • Deployments of Whip and Cage at SC Level after Vibe All stacer deployments include: Frangibolt and Motor trending, EOT Switch verification, Continuity verification, Runout and Stiffness testing. Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 495

EFW AXB I&T: Alignment • Alignment Testing – Requirement: <1° from spin axis – Testing Total: <2. 2” Runout < 0. 46° from spin axis • Stacer Runout is <1. 2” (0. 88”, 0. 73”, 1. 2”, 0. 94”) – Unit deployed horizontally on a g-negating track, then lifted to floats. • RSS Analysis of Tolerance Stackup: 0. 20 degree (0. 8 inches at Sphere) • Hinge, Whip and Sphere Runout is <0. 1” • Loose Stacer on Tip 0. 1” – Stiffness: 0. 003 lb/in – Fund. Frequency: 0. 43 Hz Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 496

EFW AXB I&T: Vibration • Vibration Testing – – – Mc. Cauley ETU Vibration to Qualification levels per 7417 -9019 Section 5. 4. 5 Self-shock survival from boom deployment actuations Force Limiting (C^2 = 5, f(0) = 1. 1 X f(n), CG response = 4. 25 X TLL) First Frequency: X, Y = 180 Hz, Z = 275 Hz Flight Units Random to GEVS Workmanship Levels as these are higher than the SC loads predicted by early SC acoustic testing. RBSP/EFW CDR 2009 9/30 -10/1 497

EFW AXB I&T: TV • Thermal Vacuum Testing – 2 operational cycles plus 1 survival cycle, per the requirements and limits indicated in 7417 -9019 section 5. 3. 2 – Deployment tests successful at hot and cold levels HOT DEPLOY COLD DEPLOY COMPONENT Mc. Cauley OPERA- SUR- SURTIONAL VIVAL MIN MAX Whip & Caging Mechanism -25 65 -30 70 Deploy Mechanism -25 55 -30 60 RBSP/EFW CDR 2009 9/30 -10/1 498

EFW AXB Radiation Dose Testing • Three samples were analyzed: – a 2 square inch sample of Aluminum with Electroless Nickel Plating with Teflon Impregnate (Microlube, by Micro Plating, Inc. ), – approximately 2 feet of AXB harness with Tefzel overwrap (Gore Cable, RCN 8818, July 2008), and – a hemisphere coated with DAG-213. • Total dose of 10 Megarads at 18 rads/s, • Average gamma ray photon energy is 1. 25 Me. V. • APL Space Departments Cobalt 60 Irradiator • Maintained integrity, adhesion and surface properties. Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 499

EFW AXB Mass Properties Testing • Mass Properties Testing: – Mass: 3. 065 kg (2. 97 predict, 3. 40 NTE) • 11% Margin – Ixx = 0. 160 kg-m 2 (0. 407 kg-m 2 at Tube COM) – Iyy = 0. 122 kg-m 2 (0. 369 kg-m 2 at Tube COM) – Izz = 0. 045 kg-m 2 Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 500

EFW AXB HYPOT Testing • HYPOT Testing: – Connectors need testing for resistance to High Potential (HI POT) • Not reasonable on a part-by-part basis • Individual representative components passed – Harness tested in unit • ETU Testing showed issues to be worked: – Arc Fault at ~300 V with Whip (225 V working limit) – Sporadic AF at 900 V with Whip removed Whip Hinge – Likely potting and sheathing of Omnetics connectors • Options will be explored with minimal expected schedule impact Whip Harness Sphere Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 501

EFW AXB Anomaly Reports • CLOSED – RBSP_EFW_AXB_018 Disposition of Deploy Catch 090417 • Improved Stacer Packing • Tip Grip Accommodated in Alignment – RBSP_EFW_AR_003 AXB Motor Gap • Washer on ETU to fill gap • No modification to Flight Motors – RBSP_EFW_AR_004 Frangibolt Overtemp in Hot TV • Switches with Timing Backup • OPEN – RBSP_EFW_AR_002 AXB Spool Wiring • Open conductor • Pending further testing Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 502

EFW AXB Changes Since PDR ü Increase deploy length from 12 m to 14 m tip to tip. ü Maintaining extra coils in Stacer Can. ü Removed Deploy Heater and Thermostat. • Determined unnecessary in EFW/SOC PDR AI #29. ü Change Roller Nozzle Springs. • Lowered contact force. Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 503

EFW AXB Changes Since ETU Testing ü Add Frangibolt Switches Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 504

EFW AXB Changes Since ETU Testing ü Add Science Cable support on Direct Drive Assembly ü Spool Wheel Well ü Finalize Spool Sizing Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 505

EFW AXB Changes Since ETU Testing ü Pre. Amp Harness Support ü Additional travel range added to Sphere Clamps ü Improve bonding features around Omnetics connectors ü Add clearance to parts near stacer ü Add Sleeve for Sphere Cage Stop Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 506

EFW AXB Shipping Containers • Designed and Assembled – Vibration Shipping Crate – Tube Shipping Crate • To Be Completed – Final Crate for Shipment to APL • • • Mc. Cauley 2 Whips 2 Cages 2 Deploy Assemblies Not Assembled Most likely an update to the Vibration Shipping Crate RBSP/EFW CDR 2009 9/30 -10/1 507

EFW AXB Backup Slides • Back up slides – Redundancy is Key…. Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 508

SSL History / Heritage UCB/SSL HERITAGE (courtesy F. Mozer) Spacecraft SPB’s AXB’s Mag Booms S 3 -2 4 S 3 -3 4 2 ISEE 2 VIKING 4 FREJA 6 FIREWHEEL* 2 CRRES 2 POLAR 4 2 FAST 4 2 CLUSTER I* 16 CLUSTER II 16 THEMIS 20 10 SPARES 26 6 2 Lunar Prospector Sounding Rockets ~50 ----- 110 26 (+ 50) 15 * LAUNCH FAILURE Mc. Cauley 2 1 RBSP/EFW CDR 2009 9/30 -10/1 509

EFW AXB Design Description ID Req. Title EFW-1 Instrument Design life shall EFW-200 Instrument Calibration shall EFW-6 Instrument Orbit Inclination Operability Instrument Orbit Perigee Operability shall Instrument Orbit Apogee Operability Instrument Accommodation of Observatory Sun Off-Point Angle (Component) shall EFW-7 EFW-8 EFW-201 Mc. Cauley Priority Requirement Body or Section Heading 3 Functional Requirements shall 3. 1 Functional, performance and general design requirments be designed for a total lifetime duration of 2 years plus 60 days. be calibrated prior to launch, and be designed to accommodate additional in-flight calibration be capable of operating in an orbit with an inclination of 10° ± 0. 25°. be capable of operating in an orbit where perigee altitude is between 500 km and 675 km (TBR). be capable of operating in an orbit where apogee altitude is between 30, 050 km and 31, 250 km (TBR). shall be capable of collecting required science measurements under the condition where the offpointing angle between the spin axis of each observatory and the Sun-Earth line during nominal operations does not exceed 25 degrees North or South of the ecliptic plane, or 25 degrees East or West in the ecliptic plane, where "north" and "south" are with respect to an ecliptic coordinate system. RBSP/EFW CDR 2009 9/30 -10/1 510

EFW AXB Design Description ID Req. Title EFW-202 Instrument Accommodation of Observatory Sun Off-Point Angle (Composite) shall EFW-9 Instrument Accommodation of Observatory Operational Spin Rate Range Instrument Accommodation of Observatory Selected Operational Spin Rate shall EFW-11 Instrument Accommodation of Observatory Selected Spin Rate Stability shall EFW-203 Instrument Accommodation of Observatory Commissioning Spin Rate Range shall EFW-10 Mc. Cauley Priority Requirement Body or Section Heading 3 Functional Requirements shall 3. 1 Functional, performance and general design requirments be capable of collecting required science measurements under the condition where the total off-pointing angle between the spin axis of each observatory and the Sun-Earth line during nominal operations is greater than 15 degrees, and does not exceed 27 degrees. be capable of operating nominally within an observatory spin rate range of no less than 4 rpm and no more than 6 rpm. be capable of collecting required science measurements at a specific, optimal spin rate selected for both observatories that is within the specified allowable range be capable of collecting required science measurements at an observatory spin rate that is maintained to within +/- 0. 25 rpm of the in-flight selected value, except during maneuvers. be capable of accommodating an observatory spin rate during commissioning period activities within a range between 3 RPM (TBR) and 15 RPM (TBR). RBSP/EFW CDR 2009 9/30 -10/1 511

EFW AXB Design Description ID Req. Title EFW-12 Instrument Accommodation of Unattended Mission Operations EFW Instrument Complement shall Functionally Identical EFW Instrument Suites EFW - Spacecraft ICD Compliance EFW Instrument Availability shall EFW Spin Axis Measurement Sensitivity Validty shall EFW-21 EFW-22 EFW-23 EFW-24 EFW-209 Mc. Cauley Priority Requirement Body or Section Heading 3 Functional Requirements shall 3. 1 Functional, performance and general design requirments be designed to accommodate periods of unattended mission operations (unstaffed MOC) during the operational phase of the mission of up to TBD hours consist of four orthogonally oriented, boom-mounted spin-plane boom-mounted sensors, an Electronics Box, and two axial boom mounted sensors with harness as defined in the Spacecraft to EFW ICD. be functionally identical. comply with the EFW-to-Spacecraft interface control documents (ICDs). be designed to be available for the collection of its required measurements at least 99% of the time during the operational phase of the mission meet Spin Axis measurement sensitivity requirements outside time periods defined as follows: the interval where the aft axial boom is shadowed by the spacecraft or solar panels, and 25 seconds after the end of such periods. (TBR) RBSP/EFW CDR 2009 9/30 -10/1 512

EFW AXB Design Description ID Req. Title EFW-51 Measure Spin Axis DC Electric Field (Survey) shall EFW-52 Measure Spin Axis DC Electric Field (Burst) shall EFW-54 EFW Axial E-Field Booms Mc. Cauley Priority Requirement Body or Section Heading 3 Functional Requirements shall 3. 1 Functional, performance and general design requirments measure axial electric field components (survey), as follows: -- frequency range: DC to 15 Hz; -- magnitude range: 2 m. V/m - 500 m. V/m; -- cadence: 32 vectors/second; -- sensitivity: 4 m. V/m or 20% for R > 3. 5 Re, 6 m. V/m or 20% for 3. 5 Re > R > 2. 5 Re, 12 m. V/m or 20% for R < 2. 5 Re. measure axial electric field components (burst), as follows: -- frequency range: DC to 256 Hz; -- magnitude range: 0. 4 - 500 m. V/m; -- cadence: 512 samples per second; -- sensitivity: 1 m. V/m or 10% @ 50 Hz (TBR). Required Components to Achieve Above be capable of deploying 6 meters with an E-Field sensor preamp at the end capable of measuring EFields to 400 k. Hz RBSP/EFW CDR 2009 9/30 -10/1 513

EFW AXB Design Description ID Req. Title EFW-54 a EFW Axial E-Field Booms shall EFW-56 EFW Harnessing shall EFW-61 EFW Power Control EFW-65 EFW Main Power Max Voltage shall EFW-66 EFW Main Power Turn Off shall EFW-68 EFW AXB Deployment Power shall EFW-69 EFW Survival Heaters shall Mc. Cauley Priority Requirement Body or Section Heading 3 Functional Requirements shall 3. 1 Functional, performance and general design requirments Required Components to Achieve Above Deploy the AXB sensors within +/- 1 degree of the AXB deployment system axis connect the SPB, AXB, IDPU, EMFISIS/MAG and EMFISIS/SCM units together as detailed in the ICDs contain circuitry to open SPB and AXB doors and deploy sensors 3. 2 Power allocations and related requirements tolerate without damage a maximum input voltage of 40 V indefinitely as defined in the ICD tolerate without damage having power removed without notice as defined in the ICD not exceed 4. 0 Amps from the EFW AXB Deployment Service accommodate survival heaters up to 1/2 nominal power at 22 V bus voltage, or approximately 113 Ohms. RBSP/EFW CDR 2009 9/30 -10/1 514

EFW AXB Design Description ID Req. Title EFW-72 EFW-73 EFW AXB Whip Release Power EFW AXB Stacer Release Power EFW AXB Motor Power shall not exceed 2. 0 Amps at 28 V shall not exceed 0. 2 Amps at 28 V (1. 5 A startup) 3. 4 Operational requirements shall perform as designed from -25 to +55 C (TBR) shall survive without damage from -30 to +60 C (TBR) EFW AXB Operational Temp Range EFW AXB Survival Temp Range EFW-90 EFW AXB ICD Compliance shall EFW-92 AXB Signal Test Input EFW-74 EFW-77 EFW-80 Mc. Cauley Priority Requirement Body or Section Heading 3 Functional Requirements shall 3. 3 Performance budget sub-allocations with respect to system budgets 3. 6 Interfaces to the spacecraft bus comply with the requirements and constraints imposed by all relevant instrument-to-spacecraft interface control documents (ICDs). 3. 8 System test Interfaces provide a connector for test input to the sensor accessible when the top and bottom of the spacecraft are accessible. RBSP/EFW CDR 2009 9/30 -10/1 515

EFW AXB Design Description ID Req. Title EFW-100 EFW AXB Deployment Enable EFW-101 EFW-102 EFW Boom Pair Redundancy EFW Safing by subsystem EFW-103 EFW Total Mass shall EFW-106 EFW-107 EFW-108 EFW AXB Mass EFW AXB Tube Mass EFW Harness Mass shall EFW-132 Instrument Compliance with Contamination Control Plan shall Mc. Cauley Priority Requirement Body or Section Heading 3 Functional Requirements shall 3. 10 Fault detection and correction considerations/requirements not deploy AXB booms or fire AXB actuators without the AXB and Main power ON. 3. 11 Redundancy description be capable of powering each Efield axis separately current-limit each axis and the front end electronics required for EMPHASIS EFI signal, and the remainder of the EFW electronics 3. 12 Mass allocation The EFW shall not exceed the total allocated mass budget of 31. 17 kg (or as allocated in RBSP System Mass Budget). not exceed 3. 64 kg not exceed 1. 29 kg not exceed 2. 50 kg (TBR) 3. 15 Contamination control requirements comply with the requirements and constraints imposed by the RBSP Observatory Contamination Control Plan, APL document no. 7417 -9011 RBSP/EFW CDR 2009 9/30 -10/1 516

EFW AXB Design Description ID Req. Title EFW-133 Instrument Compliance with EM Environment Control Plan shall EFW-135 EFW ESC Control shall EFW-136 Instrument Compliance with Environmental Design and Test Requirements Document shall EFW-137 EFW Quality Assurance shall EFW-211 Instrument Range Safety shall EFW-212 Observator Naming Convention shall Mc. Cauley Priority Requirement Body or Section Heading 3 Functional Requirements 3. 15 Contamination control requirements comply with the requirements and constraints imposed by the RBSP Electromagnetic Environment Control Plan, APL document no. 7417 -9018. comply with the UCB Electrostatic Cleanliness (ESC) Plan comply with the requirements and constraints imposed by the RBSP Environmental Design and Test Requirements Document, APL document no. 7417 -9019. comply with the RBSP Performance Assurance Implementation Plan, as modified by the Compliance Matrix comply with all relevant requirements and constraints imposed by AFSPC 91 -710, Range Safety User Requirements Manual. use an observatory naming convention, as follows: -- Observatory A is the top observatory in the stacked configuration for launch; -- Observatory B is the bottom observatory in the stacked configuration for launch. RBSP/EFW CDR 2009 9/30 -10/1 517

EFW AXB Design Requirements • Mechanical Design Requirements – From 7417 -9019 RBSP Environmental Specification, Rev. H – Quasi Static Limit Load: 25 g (5 kg to 25 kg) – Factors of Safety: See Chart – Provide a fundamental frequency of greater than 50 Hz (Stowed). Mc. Cauley Factor of Safety (FOS) Type S T A T I C S I N E R/A A C N O D U O S M T I C Metallic Yield 1. 3 1. 6 Metallic Ultimate 1. 4 1. 8 Stability Ultimate 1. 4 1. 8 Composite Ultimate 1. 5 1. 9 Bonded Inserts/Joints Ultimate 1. 5 1. 9 RBSP/EFW CDR 2009 9/30 -10/1 518

EFW AXB Design Description: Materials • Materials and Properties Assumed – Metals, Yield Stress: • • • • Mc. Cauley Brass 360, 49 kpsi Aluminum, 2024 -T 8, 58 kpsi Aluminum, 2117 -T 4, 24 kpsi Aluminum, 5052 -H 32, 28 kpsi Aluminum, 6061 -T 6, 40 kpsi Beryllium Copper, #25 (C 17200), 160 kpsi Bronze C 544, 35 kpsi Copper (Oxygen-free, C 10100), N/A Elgiloy, Spring Temper Steel, SS, 18 -8, 70 kpsi Steel, SS, 300 Series, 30 kpsi Steel, SS, 400 Series, N/A Steel, SS, 17 -7 PH, CH 900, C condition, 230 kpsi Tantalum per ASTM-B 365 -98, 65 kpsi (Ultimate) Titanium, 6 Al-4 V, 120 kpsi RBSP/EFW CDR 2009 9/30 -10/1 519

EFW AXB Design Description: Materials • Materials and Properties Assumed – Composites: • Graphite Epoxy - Fiberite Hy-E 1034 C or eq (M 55) – Plastics: • • • Mc. Cauley Acrylic (Medium-high impact), 6 kpsi Black Delrin, 11 kpsi (Ultimate) White Delrin, 11 kpsi (Ultimate) Vespel SP 3, 8 kpsi (Ultimate) PEEK, 16 kpsi RBSP/EFW CDR 2009 9/30 -10/1 520

EFW AXB Design Description: Materials • Materials and Properties Assumed – Adhesives: • • • Hysol 9309 NA, 4 kpsi (Tensile shear Strength) Hysol 1 C Hysol 0151 3 M EA 1838 3 M EA 2216 – Tapes: • Kapton Tape (acrylic adhesive) – Lubricants: • Braycote 601 –or— Braycote 601 EF • DAG 154 Paint Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 521

EFW AXB Design Description: Materials • Coatings Used – – – – – Mc. Cauley Alodine per MIL-C-5541 CL 3 (Gold) Black Anodize per MIL-A-8625 Type II, Class 2 Hard Black Anodize per MIL-A-8625 Type III, Class 2 Electroless Nickel Plating with Teflon Impregnate Silver Plate per QQ-S-365 Type I, Grade A Vapor Deposited Nickel Braycote 601 –or— Braycote 601 EF DAG 154 Paint DAG 213 Paint RBSP/EFW CDR 2009 9/30 -10/1 522

EFW AXB Deploy Operations, IPDR RFA #26 1. Fire Frangibolt to release the Cage and Whip 2. Fire Frangibolt to release the Stacer 3. Deployment proceeds by running the motor to pay out the boom (<2 cm/sec). AXB boom deployment is initiated by ground command monitored by EFW Flight and SOC software. Deployment typically proceeds in small increments. Boom length at any time is determined by a turns counter, and can also be checked based on motor operation time. Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 523

EFW AXB Deploy Operations, IPDR RFA #26 A typical sequence (after whip and stacer release) is: 1. EFW and APL agree on the next deployment increment 2. The MOC enables the AXB deployment power service 3. Wait until the AXB deployment mechanism is within thermal limits 4. EFW SOC commands the EFW DPU to deploy AXB a number of clicks 5. EFW flight software powers on the motor, counts clicks, and powers off the motor after the desired number of clicks 6. MOC powers off the AXB deployment power service 7. SOC software & EFW personnel monitor the deployment Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 524

EFW AXB Deploy Fault, IPDR RFA #26 • • Single String Mission Credible AXB deployment failure mechanisms which might result in an unintended or over-long deployment and mitigations: Item Failure Mitigation AXB deployment service normally powered off by the spacecraft 3 EFW hardware or software failure outside of boom deployment intervals which would cause the system to attempt to deploy the AXB. EFW software failure during AXB boom deployment resulting in motor continuing to operate past the desired number of clicks AXB deployment clicks switch failure 4 AXB motor switch failure (fails ON) 5 Harness failure (breaks) resulting in unrestrained deployment. 1 2 1. 2. EFW watchdog resets system to motors off state EFW team requests MOC to power off deployment service if system not operating nominally. EFW team sees no clicks (or off-nominal click rate) during deployment and shuts off AXB power, resulting in a short deployment. Deployment length can be estimated based on motor on time. EFW team requests MOC to shut off AXB deployment service 1. 2. Mc. Cauley Harness contains Kevlar element which is >100 x stronger than the deployment forces. Should the deployment jam, an over-tension switch cuts off the motor well below the force level which might damage the harness. RBSP/EFW CDR 2009 9/30 -10/1 525

EFW AXB Worst Case Fault • • If no clicks are seen or the deployment runs longer than expected – terminated by ground command – MOC can terminate the AXB deployment service SOC and MOC team should be prepared to act swiftly to minimize the uncontrolled deployment time (at ~2 cm/sec). Most anomalies would be identified prior to reaching the desired deployment length Worst case: ~5 seconds to command, ~10 cm of length. Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 526

EFW AXB Tube • Structural Design – Fixed-Fixed First Frequency: 257 Hz – Tube Static Stress Margin: 10 – Buckling Force: 3600 lbs (max load: 1200 lbs) Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 527

EFW AXB Design Description: Booms Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 528

EFW AXB Design Description: Booms Stowed Configuration • Whip and Spherical Electric Fields Probe – Hinge • Torque Margin: 3. 6 • Hinge Spring to Friction • DAG 213 Coated – Whip Tube • FOS (Bending on Deploy): 2. 0 • DAG 213 Coated – Sphere • Probe and Preamp Assy • DAG 213 Coated • Cannot Clean – All Three Isolated for Potential Control – Fundamental Frequency: 23. 0 RPM • (> 4 x SC Spin Rate Rigid) Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 Preamp Hinge Whip Sphere Deployed Configuration 529

EFW AXB Design Description: I&T • ETU Flow: Stiffness Testing – Slope: 0. 003 lb/in 4. 00 3. 00 2. 00 inches 1. 00 23 -Jul 17 -Jun 0. 00 -6 -4 -2 0 2 4 -1. 00 6 8 grams 16 -Jun 3 -Jun -2. 00 -3. 00 -4. 00 Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 530

EFW AXB Design Description: I&T • Stacer Fundamental Frequency Testing – Unit deployed horizontally, then suspended vertically. • Gravitational component subtracted from frequency. – ETU Unit: 0. 43 Hz – Flight unit will be tested horizontally in Runout Test Fixture. 8 6 4 2 0 0 5 10 15 20 25 -2 -4 Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 531

EFW AXB Design Description: I&T • ETU Flow: Thermal Vacuum Testing – 2 operational cycles plus 1 survival cycle, per the requirements and limits indicated in 7417 -9019 section 5. 3. 2 – Deployment tests successful at hot and cold levels TEST COMPONENT Rod Sphere Caging Mechanism DDAD Mechanism and Stacer Mc. Cauley OPERATIONAL OPERATIONA SURVIVAL MIN L MAX MIN MAX -25 65 -30 70 -25 55 -30 60 RBSP/EFW CDR 2009 9/30 -10/1 532

EFW AXB Mate / Demate Tally Connector: JA JB JC PC JD JE PE JF PF JH PH JI PI JJ PJ Total: 23 10 5 Mc. Cauley 1 1 11 11 13 10 7 RBSP/EFW CDR 2009 9/30 -10/1 3 0 0 11 5 533

EFW AXB Blind Mates • Mate of JH to PH – During assembly of Whip to Stacer Tip Piece – The mate is hidden – Alignment is checked beforehand – Harness is checked afterward Mc. Cauley RBSP/EFW CDR 2009 9/30 -10/1 534