EFW AXB Spacecraft +Z Jeremy McCauley Aerospace Engineer

EFW AXB Spacecraft +Z Jeremy McCauley Aerospace Engineer
Space Sciences Laboratory, UCB AXB AXB McCauley RBSP/EFW CDR /30-10/1

EFW INST+SOC PEER REVIEW
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, implemented CDR RFAs: 0 (?) CDR Flight Build 28 July 2009 EFW INST+SOC PEER REVIEW

EFW AXB Overview Design Drivers Design Description
Concept Heritage Assembly Breakout Thermal ETU Integration and Testing (I&T) Changes Since ETU McCauley RBSP/EFW CDR /30-10/1

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 +55C (TBR) Interface Survival Temperature Range: -30 to +60C (TBR) McCauley RBSP/EFW CDR /30-10/1

EFW AXB Concept Axial Boom Unit (AXB)
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 McCauley RBSP/EFW CDR /30-10/1

EFW AXB Heritage Heritage Unit Added Refinements
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 McCauley RBSP/EFW CDR /30-10/1

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 McCauley RBSP/EFW CDR /30-10/1

EFW AXB Design Description: AXB
Upper Boom Unit (+Z) Lower Boom Unit (-Z) Dimensional Scale Tube Diameter 6” [15 cm] Deck Separation 43.5” [108 cm] Whip Length 13” [33 cm] Sphere Diameter 3.2” [8.0 cm] Structural Design End Supported Tube with Aluminum End Fittings Two (2) Identical Boom Units Stationary Deploy Assembly Moving DAD Stacer Whip and Spherical Electric Fields Probe McCauley RBSP/EFW CDR /30-10/1

EFW AXB Tube Assembly Structural Design
End Supported Tube: Graphite Epoxy, M55 (Layup: -60/60/0/0/60/-60 [quasi-isotropic]) Fixed-Fixed First Frequency: 257 Hz Tube Static Stress Margin: 10 End Fittings: Al 6061-T6 Lower Support includes a drumhead flexure design Currently ºC dT Joint Epoxy: Hysol 9309NA Bond Shear Stress Margin: 30.3 Flexure Tube End Fitting Flexure at dT=52ºC McCauley RBSP/EFW CDR /30-10/1

EFW AXB Tube Testing Structural Testing Thermal cycling Static loads
Structural loads testing Integrated to SC McCauley RBSP/EFW CDR /30-10/1

EFW AXB Design Description: Booms
Stowed Configuration Boom Design Stationary Deploy Assy Moving DAD Stacer Whip and Spherical Electric Fields Probe Whip Deploy Assy DAD Stacer Deployed Configuration McCauley RBSP/EFW CDR /30-10/1

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 McCauley RBSP/EFW CDR /30-10/1

EFW AXB Design Description: Cage
Stowed Configuration Sphere Caging Mechanism 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 AC Test Contact for Ground Operations Torque Margin: 40.9 Spring to Friction Drag Green Tag Enable Plug/ Ground Test Plug DAD Plungers Frangibolt AC Test Contact Enable Plug Deployed Configuration McCauley RBSP/EFW CDR /30-10/1

EFW AXB Design Description: Frangibolt
TiNi Frangibolt 500 lb Retention Force For Launch Loads Only Static Margin: 14 Resettable 25 28 Vdc 95°C Actuation Temperature Trending Data McCauley RBSP/EFW CDR /30-10/1

EFW AXB Design Description: Direct Drive
Frangibolt Motor Slip Ring Sense Switches Spool Direct Drive Assembly Stacer Frangibolt Release Harness Spool: Max Capacity 6.66 meters 0.068” diameter cable Motor Drive Mechanism: Globe A1430 Motor (1000:1 gear ratio) Sense Switches: Stacer Release, End of Wire and Turn Counter (Newark, 1HM19) 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 Torque to Retract Stacer) Harness McCauley RBSP/EFW CDR /30-10/1

EFW AXB Cable Load Path Cable Force Path Glue Joint Tie Off Point
Force is carried completely in Kevlar overwrap Static Margin: >100 McCauley RBSP/EFW CDR /30-10/1

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 McCauley RBSP/EFW CDR /30-10/1

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 Springs designed to 1.6 lb minimum radial force Force Margin: 2.1 DAD Springs to Friction Roller Nozzle #2 DAD Springs Lock Wheel Assy Stowed Configuration Deployed Configuration McCauley RBSP/EFW CDR /30-10/1

EFW AXB Design Description: Stacer
Helical Spring Deployed Acts as a Rigid Tube Spin Adjusted Resonance: 26.5 RPM Force Margin: > 3 Stacer Force to Friction Deployed Configuration MAIN STACER PROPERTIES [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 Stacer McCauley RBSP/EFW CDR /30-10/1

EFW AXB Design Description: Whip
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 Sphere Probe and Preamp Assy Cannot Clean DAG 213 surfaces All Three Isolated for Potential Control Fundamental Frequency: 23.0 RPM (> 4x SC Spin Rate  Rigid) Sphere Internal View Preamp Hinge Whip Sphere Deployed Configuration McCauley RBSP/EFW CDR /30-10/1

EFW AXB Design Description: Stress Margins
Critical Part 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 McCauley RBSP/EFW CDR /30-10/1

EFW AXB Glue Bond Margins
Epoxy: Hysol 9309NA 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 2418 DAD Rod to DAD Tip 0.349 221 2.17 101 Tip Tube to Tip End 1.077 683 3.17 214 Tip to Tip Tube Tip to Safety Pin 1.127 715 224 * Joint Strength is derated according to surface preparation requirements as discussed in HTN , dated 06/15/2000, as received from Chris Smith, UCB/SSL. McCauley RBSP/EFW CDR /30-10/1

EFW AXB Glue Bond Margins
Tip to Safety Pin Tip to Tip Tube Tip Tube to Tip End DAD Rod to DAD Tip Whip to Hinge Whip to Sphere McCauley RBSP/EFW CDR /30-10/1

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 McCauley RBSP/EFW CDR /30-10/1

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, 300s immersion) Electroless Nickel Plating with Teflon Impregnate Stationary Deploy Assy: End Supported Tube M55 Graphite Epoxy Aluminum End Fittings McCauley RBSP/EFW CDR /30-10/1

EFW INST+SOC PEER REVIEW
EFW AXB Long Lead Items Frangibolts Ordered: August 2009 ~10 week lead Gore Cable In House Motor Stacer 28 July 2009 EFW INST+SOC PEER REVIEW

EFW AXB Order of Assembly
Preamp Mech Assembly Assemble Caging Mech Test Preamp PWB Whip and Cage Mechanical Functional Integrate Whip and Cage Assemble Sphere, Whip and Preamp Assemble Whip Paint: Whip, Stacer and Sphere Whip and Cage Electrical Functional Assemble Stacer Assemble Stacer Assembly Assemble Doors Assemble DAD Assemble Stacer Mechanism Motor Burn In Harness Motor Harness Assembly Harness SW1 Assemble Direct Drive (-500) Stacer Mech Functional, Length & Runout Measurement, Continuity Check Harness Diode Block PER 28 July 2009 EFW INST+SOC PEER REVIEW

EFW AXB I&T: Environmental Test Matrix
RBSP EFW ENVIRONMENTAL TEST MATRIX HARDWARE MECHANICAL ELECTRICAL THERMAL CONTAM. OTHER COMPONENT (ITEM) QUANTITY SUPPLIER ALIGNMENT MODAL SURVEY STATIC LOAD RANDOM VIBRATION SINE VIBRATION ACOUSTIC PROOF TEST CLAMP BAND SHOCK VENTING/PRESS. PROFILE MASS PROPERTIES MECH Fn - DEPLOY INTERFACE VERIFICATION EMFISIS INTERFACE TEST BONDING AND ISOLATION TURN ON/OFF TRANSIENTS CONDUCTED EMISSIONS CONDUCTED SUSCEPTIBILITY RADIATED EMISSIONS RADIATED SUSCEPTIBILITY ESD DISCHARGE TEST SELF COMPATIBILITY THERMAL VACUUM (# CYCLES) THERMAL BALANCE ESC AND GROUNDING DC MAGNETICS BAKEOUT RADIATION DEEP DIELECTRIC DISCHARGE FAILURE FREE HOURS ETU 1 UCB T14 T1 A1, T4 M1 T12 T6 T5 T7 T 3 M2 Instrument 2 2,T16 T11 100 EFI SPB 8 A2 5 SPB Pre-amp 7 T9 EFI AXB 4 AXB Deploy Mech A1 T3 T13 AXB less whip (*) T15 T4 AXB Pre-amp AXB Cage/whip Tube T2 IDPU M A,T Instrument Harness M3 T10 Instrument on S/C A McCauley RBSP/EFW CDR /30-10/1

EFW AXB Environmental Testing
PER Integrate Stacer, Whip and Cage Electrical Functional Test Integrated Vibration Test Electrical Functional Test Stacer Mech Functional, Length & Runout Measurement, Continuity Check Whip and Cage Mechanical Functional Electrical Functional Test Dis-Integrate Stacer, Whip and Cage Whip and Cage TV Hot Deploy Whip and Cage TV Cold Deploy Integrate Stacer, Whip and Cage Mass Properties Science Calibration Stacer Mech TV Hot Deploy, Length & Runout Measurement, Continuity Check Stacer Mech TV Hot Deploy, Length & Runout Measurement, Continuity Check PSR 28 July 2009 EFW INST+SOC PEER REVIEW

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. McCauley RBSP/EFW CDR /30-10/1

EFW AXB I&T: Alignment Alignment Testing Stiffness: 0.003 lb/in
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”, 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: lb/in Fund. Frequency: 0.43 Hz McCauley RBSP/EFW CDR /30-10/1

EFW AXB I&T: Vibration Vibration Testing
ETU Vibration to Qualification levels per 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. McCauley RBSP/EFW CDR /30-10/1

Whip & Caging Mechanism
EFW AXB I&T: TV Thermal Vacuum Testing 2 operational cycles plus 1 survival cycle, per the requirements and limits indicated in section 5.3.2 Deployment tests successful at hot and cold levels HOT DEPLOY COLD DEPLOY COMPONENT OPERA-TIONAL MIN OPERA-TIONAL MAX SUR-VIVAL MIN SUR-VIVAL MAX Whip & Caging Mechanism -25 65 -30 70 Deploy Mechanism 55 60 McCauley RBSP/EFW CDR /30-10/1

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, RCN8818, 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 MeV. APL Space Departments Cobalt 60 Irradiator Maintained integrity, adhesion and surface properties. McCauley RBSP/EFW CDR /30-10/1

EFW AXB Mass Properties Testing
Mass Properties Testing: to be completed Mass: kg (2.97 predict, 3.40 NTE) 11% Margin Ixx = kg-m2 (0.407 kg-m at Tube COM) Iyy = Izz = McCauley RBSP/EFW CDR /30-10/1

EFW AXB HYPOT Testing HYPOT Testing: to be completed
Connectors need testing for resistance to High Potential (HI POT) Not reasonable on a part by part basis Harness will be tested in unit, prior to Preamp installation Whip Hinge Whip Harness Sphere McCauley RBSP/EFW CDR /30-10/1

EFW AXB Anomaly Reports
CLOSED RBSP_EFW_AXB_018 Disposition of Deploy Catch 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 McCauley RBSP/EFW CDR /30-10/1

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

EFW AXB Changes Since ETU Testing
Add Frangibolt Switches McCauley RBSP/EFW CDR /30-10/1

Add Science Cable support on Direct Drive Assembly Spool Wheel Well Finalize Spool Sizing McCauley RBSP/EFW CDR /30-10/1

PreAmp Harness Support Additional travel range added to Sphere Clamps Improve bonding features around Omnetics connectors Add clearance to parts near stacer Add Sleeve for Sphere Cage Stop McCauley RBSP/EFW CDR /30-10/1

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

EFW AXB Backup Slides Back up slides Redundancy is Key…. McCauley
RBSP/EFW CDR /30-10/1

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

EFW AXB Design Description
ID Req. Title Priority Requirement Body or Section Heading 3 Functional Requirements 3.1 Functional, performance and general design requirments EFW-1 Instrument Design life shall be designed for a total lifetime duration of 2 years plus 60 days. EFW-200 Instrument Calibration be calibrated prior to launch, and be designed to accommodate additional in-flight calibration EFW-6 Instrument Orbit Inclination Operability be capable of operating in an orbit with an inclination of 10° ± 0.25°. EFW-7 Instrument Orbit Perigee Operability be capable of operating in an orbit where perigee altitude is between 500 km and 675 km (TBR). EFW-8 Instrument Orbit Apogee Operability be capable of operating in an orbit where apogee altitude is between 30,050 km and 31,250 km (TBR). EFW-201 Instrument Accommodation of Observatory Sun Off-Point Angle (Component) shall be capable of collecting required science measurements under the condition where the off-pointing 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. McCauley RBSP/EFW CDR /30-10/1

ID Req. Title Priority Requirement Body or Section Heading 3 Functional Requirements 3.1 Functional, performance and general design requirments EFW-202 Instrument Accommodation of Observatory Sun Off-Point Angle (Composite) shall 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. EFW-9 Instrument Accommodation of Observatory Operational Spin Rate Range be capable of operating nominally within an observatory spin rate range of no less than 4 rpm and no more than 6 rpm. EFW-10 Instrument Accommodation of Observatory Selected Operational Spin Rate be capable of collecting required science measurements at a specific, optimal spin rate selected for both observatories that is within the specified allowable range EFW-11 Instrument Accommodation of Observatory Selected Spin Rate Stability be capable of collecting required science measurements at an observatory spin rate that is maintained to within +/ rpm of the in-flight selected value, except during maneuvers. EFW-203 Instrument Accommodation of Observatory Commissioning Spin Rate Range be capable of accommodating an observatory spin rate during commissioning period activities within a range between 3 RPM (TBR) and 15 RPM (TBR). McCauley RBSP/EFW CDR /30-10/1

ID Req. Title Priority Requirement Body or Section Heading 3 Functional Requirements 3.1 Functional, performance and general design requirments EFW-12 Instrument Accommodation of Unattended Mission Operations shall be designed to accommodate periods of unattended mission operations (unstaffed MOC) during the operational phase of the mission of up to TBD hours EFW-21 EFW Instrument Complement 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. EFW-22 Functionally Identical EFW Instrument Suites be functionally identical. EFW-23 EFW - Spacecraft ICD Compliance comply with the EFW-to-Spacecraft interface control documents (ICDs). EFW-24 EFW Instrument Availability 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 EFW-209 EFW Spin Axis Measurement Sensitivity Validty 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) McCauley RBSP/EFW CDR /30-10/1

ID Req. Title Priority Requirement Body or Section Heading 3 Functional Requirements 3.1 Functional, performance and general design requirments EFW-51 Measure Spin Axis DC Electric Field (Survey) shall measure axial electric field components (survey), as follows: frequency range: DC to 15Hz; magnitude range: 2 mV/m mV/m; cadence: 32 vectors/second; sensitivity: mV/m or 20% for R > 3.5 Re, mV/m or 20% for 3.5 Re > R > 2.5 Re, mV/m or 20% for R < 2.5 Re. EFW-52 Measure Spin Axis DC Electric Field (Burst) measure axial electric field components (burst), as follows: frequency range: DC to 256 Hz; magnitude range: mV/m; cadence: 512 samples per second; sensitivity: 1 mV/m or 50 Hz (TBR). Required Components to Achieve Above EFW-54 EFW Axial E-Field Booms be capable of deploying 6 meters with an E-Field sensor preamp at the end capable of measuring E-Fields to 400 kHz McCauley RBSP/EFW CDR /30-10/1

ID Req. Title Priority Requirement Body or Section Heading 3 Functional Requirements 3.1 Functional, performance and general design requirments Required Components to Achieve Above EFW-54a EFW Axial E-Field Booms shall Deploy the AXB sensors within +/- 1 degree of the AXB deployment system axis EFW-56 EFW Harnessing connect the SPB, AXB, IDPU, EMFISIS/MAG and EMFISIS/SCM units together as detailed in the ICDs EFW-61 EFW Power Control contain circuitry to open SPB and AXB doors and deploy sensors 3.2 Power allocations and related requirements EFW-65 EFW Main Power Max Voltage tolerate without damage a maximum input voltage of 40V indefinitely as defined in the ICD EFW-66 EFW Main Power Turn Off tolerate without damage having power removed without notice as defined in the ICD EFW-68 EFW AXB Deployment Power not exceed 4.0 Amps from the EFW AXB Deployment Service EFW-69 EFW Survival Heaters accommodate survival heaters up to 1/2 nominal power at 22V bus voltage, or approximately 113 Ohms. McCauley RBSP/EFW CDR /30-10/1

ID Req. Title Priority Requirement Body or Section Heading 3 Functional Requirements 3.3 Performance budget sub-allocations with respect to system budgets EFW-72 EFW AXB Whip Release Power shall not exceed 2.0 Amps at 28V EFW-73 EFW AXB Stacer Release Power EFW-74 EFW AXB Motor Power not exceed 0.2 Amps at 28V (1.5A startup) 3.4 Operational requirements EFW-77 EFW AXB Operational Temp Range perform as designed from -25 to +55C (TBR) EFW-80 EFW AXB Survival Temp Range survive without damage from -30 to +60C (TBR) 3.6 Interfaces to the spacecraft bus EFW-90 EFW AXB ICD Compliance comply with the requirements and constraints imposed by all relevant instrument-to-spacecraft interface control documents (ICDs). 3.8 System test Interfaces EFW-92 AXB Signal Test Input provide a connector for test input to the sensor accessible when the top and bottom of the spacecraft are accessible. McCauley RBSP/EFW CDR /30-10/1

ID Req. Title Priority Requirement Body or Section Heading 3 Functional Requirements 3.10 Fault detection and correction considerations/requirements EFW-100 EFW AXB Deployment Enable shall not deploy AXB booms or fire AXB actuators without the AXB and Main power ON. 3.11 Redundancy description EFW-101 EFW Boom Pair Redundancy be capable of powering each Efield axis separately. EFW-102 EFW Safing by subsystem 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 EFW-103 EFW Total Mass The EFW shall not exceed the total allocated mass budget of 31.17kg (or as allocated in RBSP System Mass Budget). EFW-106 EFW AXB Mass not exceed 3.64 kg EFW-107 EFW AXB Tube Mass not exceed 1.29 kg EFW-108 EFW Harness Mass not exceed 2.50 kg (TBR) 3.15 Contamination control requirements EFW-132 Instrument Compliance with Contamination Control Plan comply with the requirements and constraints imposed by the RBSP Observatory Contamination Control Plan, APL document no McCauley RBSP/EFW CDR /30-10/1

ID Req. Title Priority Requirement Body or Section Heading 3 Functional Requirements 3.15 Contamination control requirements EFW-133 Instrument Compliance with EM Environment Control Plan shall comply with the requirements and constraints imposed by the RBSP Electromagnetic Environment Control Plan, APL document no EFW-135 EFW ESC Control comply with the UCB Electrostatic Cleanliness (ESC) Plan EFW-136 Instrument Compliance with Environmental Design and Test Requirements Document comply with the requirements and constraints imposed by the RBSP Environmental Design and Test Requirements Document, APL document no EFW-137 EFW Quality Assurance comply with the RBSP Performance Assurance Implementation Plan, as modified by the Compliance Matrix EFW-211 Instrument Range Safety comply with all relevant requirements and constraints imposed by AFSPC , Range Safety User Requirements Manual. EFW-212 Observator Naming Convention 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. McCauley RBSP/EFW CDR /30-10/1

EFW AXB Design Requirements
Mechanical Design Requirements From 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). Factor of Safety (FOS) Type S T A I C N E R / A A C N O D U O S M T Metallic Yield 1.3 1.6 Metallic Ultimate 1.4 1.8 Stability Ultimate Composite Ultimate 1.5 1.9 Bonded Inserts/Joints Ultimate McCauley RBSP/EFW CDR /30-10/1

EFW AXB Design Description: Materials
Materials and Properties Assumed Metals, Yield Stress: Brass 360, 49 kpsi Aluminum, 2024-T8, 58 kpsi Aluminum, 2117-T4, 24 kpsi Aluminum, 5052-H32, 28 kpsi Aluminum, 6061-T6, 40 kpsi Beryllium Copper, #25 (C17200), 160 kpsi Bronze C544, 35 kpsi Copper (Oxygen-free, C10100), 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, CH900, C condition, 230 kpsi Tantalum per ASTM-B365-98, 65 kpsi (Ultimate) Titanium, 6Al-4V, 120 kpsi McCauley RBSP/EFW CDR /30-10/1

Materials and Properties Assumed Composites: Graphite Epoxy - Fiberite Hy-E 1034C or eq (M55) Plastics: Acrylic (Medium-high impact), 6kpsi Black Delrin, 11 kpsi (Ultimate) White Delrin, 11 kpsi (Ultimate) Vespel SP3, 8 kpsi (Ultimate) PEEK, 16 kpsi McCauley RBSP/EFW CDR /30-10/1

Materials and Properties Assumed Adhesives: Hysol 9309NA, 4 kpsi (Tensile shear Strength) Hysol 1C Hysol 0151 3M EA1838 3M EA 2216 Tapes: Kapton Tape (acrylic adhesive) Lubricants: Braycote 601 –or— Braycote 601 EF DAG 154 Paint McCauley RBSP/EFW CDR /30-10/1

Coatings Used 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 DAG154 Paint DAG213 Paint McCauley RBSP/EFW CDR /30-10/1

EFW AXB Deploy Operations, IPDR RFA #26
Fire Frangibolt to release the Cage and Whip Fire Frangibolt to release the Stacer Deployment proceeds by running the motor to pay out the boom (<2cm/sec). AXB boom deployment is initiated by ground command and 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. McCauley RBSP/EFW CDR /30-10/1

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

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 1 EFW hardware or software failure outside of boom deployment intervals which would cause the system to attempt to deploy the AXB. AXB deployment service normally powered off by the spacecraft 2 EFW software failure during AXB boom deployment resulting in motor continuing to operate past the desired number of clicks EFW watchdog resets system to motors off state EFW team requests MOC to power off deployment service if system not operating nominally. 3 AXB deployment clicks switch failure 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. 4 AXB motor switch failure (fails ON) EFW team requests MOC to shut off AXB deployment service 5 Harness failure (breaks) resulting in unrestrained deployment. Harness contains Kevlar element which is >100x 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. McCauley RBSP/EFW CDR /30-10/1

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 ~2cm/sec). Most anomalies would be identified prior to reaching the desired deployment length Worst case: ~5 seconds to command, ~10cm of length. McCauley RBSP/EFW CDR /30-10/1

EFW AXB Tube Structural Design Fixed-Fixed First Frequency: 257 Hz
Tube Static Stress Margin: 10 Buckling Force: 3600 lbs (max load: 1200 lbs) McCauley RBSP/EFW CDR /30-10/1

McCauley RBSP/EFW CDR /30-10/1

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 Sphere Probe and Preamp Assy Cannot Clean All Three Isolated for Potential Control Fundamental Frequency: 23.0 RPM (> 4x SC Spin Rate  Rigid) Preamp Hinge Whip Sphere Deployed Configuration McCauley RBSP/EFW CDR /30-10/1

EFW AXB Design Description: I&T
ETU Flow: Stiffness Testing Slope: lb/in inches grams McCauley RBSP/EFW CDR /30-10/1

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. McCauley RBSP/EFW CDR /30-10/1

ETU Flow: Thermal Vacuum Testing 2 operational cycles plus 1 survival cycle, per the requirements and limits indicated in section 5.3.2 Deployment tests successful at hot and cold levels TEST COMPONENT OPERATIONAL MIN OPERATIONAL MAX SURVIVAL MIN SURVIVAL MAX Rod Sphere Caging Mechanism -25 65 -30 70 DDAD Mechanism and Stacer 55 60 McCauley RBSP/EFW CDR /30-10/1

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 1 11 13 7 3 McCauley RBSP/EFW CDR /30-10/1

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 McCauley RBSP/EFW CDR /30-10/1

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McCauley RBSP/EFW CDR /30-10/1

EFW AXB Spacecraft +Z Jeremy McCauley Aerospace Engineer

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