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EFW AXB. Spacecraft +Z. Jeremy McCauley Aerospace Engineer Space Sciences Laboratory, UCB [email protected] AXB. AXB. 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

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efw axb
EFW AXB

Spacecraft +Z

Jeremy McCauley

Aerospace Engineer

Space Sciences Laboratory, UCB

[email protected]

AXB

AXB

RBSP/EFW CDR 2009 9/30-10/1

efw axb overall flow
EFW AXBOverall 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
    • RFAs: 0 (?)

CDR

Flight Build

EFW INST+SOC PEER REVIEW

efw axb overview
EFW AXBOverview
  • Design Drivers
  • Design Description
    • Concept
    • Heritage
    • Assembly Breakout
    • Thermal
  • ETU Integration and Testing (I&T)
  • Changes Since ETU

RBSP/EFW CDR 2009 9/30-10/1

efw axb design drivers
EFW AXBDesign 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)

RBSP/EFW CDR 2009 9/30-10/1

efw axb concept
EFW AXBConcept

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

RBSP/EFW CDR 2009 9/30-10/1

efw axb heritage
EFW AXBHeritage
  • 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb order of deploy
EFW AXBOrder 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description axb
EFW AXBDesign Description: AXB

Upper Boom Unit (+Z)

Lower Boom Unit (-Z)

  • 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb tube assembly
EFW AXBTube 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 89.1 lbf @ 52ºC dT
    • Joint Epoxy: Hysol 9309NA
    • Bond Shear Stress Margin: 30.3

Flexure

Tube

End Fitting

Flexure at

dT=52ºC

RBSP/EFW CDR 2009 9/30-10/1

efw axb tube testing
EFW AXBTube Testing
  • Structural Testing
    • Thermal cycling
    • Static loads
    • Structural loads testing
      • Integrated to SC

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description booms
EFW AXBDesign 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description booms1
EFW AXBDesign 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description cage
EFW AXBDesign 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description frangibolt
EFW AXBDesign Description: Frangibolt
  • TiNi Frangibolt
    • 500 lb Retention Force
      • For Launch Loads Only
      • Static Margin: 14
    • Resettable
    • 25 W @ 28 Vdc
    • 95°C Actuation Temperature
    • Trending Data

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description direct drive
EFW AXBDesign Description: Direct Drive

Frangibolt

Slip Ring

Motor

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

RBSP/EFW CDR 2009 9/30-10/1

efw axb cable load path
EFW AXBCable Load Path

Glue Joint

  • Cable Force Path
    • Force is carried completely in Kevlar overwrap
    • Static Margin: >100

Tie Off Point

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description nozzle
EFW AXBDesign Description: Nozzle
  • Roller Nozzle #1
    • Centering of the Stacer
    • Resist SC Forces
      • Springs designed to 1.6 lb minimum radial force

Rollers

Rocker Arms

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description dad
EFW AXBDesign 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description stacer
EFW AXBDesign Description: Stacer
  • Stacer
    • Helical Spring
    • Deployed Acts as a Rigid Tube
      • Spin Adjusted Resonance: 26.5 RPM
    • Force Margin: > 3
      • Stacer Force to Friction

Deployed Configuration

Stacer

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description whip
EFW AXBDesign 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
      • DAG 213 Coated
    • Sphere
      • Probe and Preamp Assy
      • DAG 213 Coated
    • 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb glue bond margins
EFW AXBGlue Bond Margins

* 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.

RBSP/EFW CDR 2009 9/30-10/1

efw axb glue bond margins1
EFW AXBGlue Bond Margins

Whip to Hinge

Whip to Sphere

DAD Rod to DAD Tip

Tip Tube to Tip End

Tip to Tip Tube

Tip to Safety Pin

RBSP/EFW CDR 2009 9/30-10/1

efw axb design spreadsheets
EFW AXBDesign 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb thermal
EFW AXBThermal
  • 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:
    • Alodine (1500, Clear, 300s immersion)
    • Electroless Nickel Plating with Teflon Impregnate
  • End Supported Tube
    • M55 Graphite Epoxy
  • Aluminum End Fittings
    • Alodine (1500, Clear, 300s immersion)

RBSP/EFW CDR 2009 9/30-10/1

efw axb long lead items
EFW AXBLong Lead Items
  • Frangibolts
    • Ordered: August 2009
    • ~10 week lead
  • Gore Cable
    • In House
  • Motor
    • In House
  • Stacer
    • In House

EFW INST+SOC PEER REVIEW

efw axb order of assembly
EFW AXBOrder of Assembly

Assemble Caging Mech

Preamp Mech Assembly

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)

StacerMech Functional,Length & Runout Measurement, Continuity Check

Harness Diode Block

PER

EFW INST+SOC PEER REVIEW

efw axb i t environmental test matrix
EFW AXBI&T: Environmental Test Matrix

RBSP/EFW CDR 2009 9/30-10/1

efw axb environmental testing
EFW AXBEnvironmental Testing

Integrate Stacer, Whip and Cage

Integrated Vibration Test

PER

Electrical Functional Test

Electrical Functional Test

StacerMech Functional,Length & Runout Measurement, Continuity Check

Whip and Cage Mechanical Functional

Dis-Integrate Stacer, Whip and Cage

Electrical Functional Test

Whip and Cage TV Hot Deploy

Whip and Cage TV Cold Deploy

Integrate Stacer, Whip and Cage

Mass Properties

Science Calibration

StacerMechTV Hot Deploy,Length & Runout Measurement, Continuity Check

StacerMechTV Hot Deploy,Length & Runout Measurement, Continuity Check

PSR

EFW INST+SOC PEER REVIEW

efw axb i t deployments
EFW AXBI&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.

RBSP/EFW CDR 2009 9/30-10/1

efw axb i t alignment
EFW AXBI&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”, 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb i t vibration
EFW AXBI&T: Vibration
  • Vibration Testing
    • 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

efw axb i t tv
EFW AXBI&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

RBSP/EFW CDR 2009 9/30-10/1

efw axb radiation dose testing
EFW AXBRadiation 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.

RBSP/EFW CDR 2009 9/30-10/1

efw axb mass properties testing
EFW AXBMass Properties Testing
  • Mass Properties Testing: to be completed
    • Mass: 3.065 kg (2.97 predict, 3.40 NTE)
      • 11% Margin
    • Ixx = 0.160 kg-m2 (0.407 kg-m at Tube COM)
    • Iyy =
    • Izz =

RBSP/EFW CDR 2009 9/30-10/1

efw axb hypot testing
EFW AXBHYPOT 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb anomaly reports
EFW AXBAnomaly 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb changes since pdr
EFW AXBChanges 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.

RBSP/EFW CDR 2009 9/30-10/1

efw axb changes since etu testing
EFW AXBChanges Since ETU Testing
  • Add Frangibolt Switches

RBSP/EFW CDR 2009 9/30-10/1

efw axb changes since etu testing1
EFW AXBChanges Since ETU Testing
  • Add Science Cable support on Direct Drive Assembly
  • Spool Wheel Well
  • Finalize Spool Sizing

RBSP/EFW CDR 2009 9/30-10/1

efw axb changes since etu testing2
EFW AXBChanges Since ETU Testing
  • 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb shipping containers
EFW AXBShipping 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb backup slides
EFW AXBBackup Slides
  • Back up slides
    • Redundancy is Key….

RBSP/EFW CDR 2009 9/30-10/1

slide44

SSL History / Heritage

UCB/SSL HERITAGE(courtesy F. Mozer)

Spacecraft SPB’s AXB’s Mag Booms

S3-2 4

S3-3 4 2

ISEE 2

VIKING 4

FREJA 6

FIREWHEEL* 2

CRRES 2

POLAR 4 2

FAST 4 2 2

CLUSTER I* 16

CLUSTER II 16

THEMIS 20 10 10

SPARES 26 6 2

Lunar Prospector 1

Sounding Rockets ~50

----- ----- -----

110 26 (+ 50) 15

* LAUNCH FAILURE

McCauley

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description
EFW AXBDesign Description

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description1
EFW AXBDesign Description

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description2
EFW AXBDesign Description

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efw axb design description3
EFW AXBDesign Description

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description4
EFW AXBDesign Description

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description5
EFW AXBDesign Description

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description6
EFW AXBDesign Description

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description7
EFW AXBDesign Description

RBSP/EFW CDR 2009 9/30-10/1

efw axb design requirements
EFW AXBDesign 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).

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description materials
EFW AXBDesign 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description materials1
EFW AXBDesign Description: Materials
  • 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description materials2
EFW AXBDesign Description: Materials
  • 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description materials3
EFW AXBDesign Description: Materials
  • 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb deploy operations ipdr rfa 26
EFW AXBDeploy 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.

RBSP/EFW CDR 2009 9/30-10/1

efw axb deploy operations ipdr rfa 261
EFW AXBDeploy 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb deploy fault ipdr rfa 26
EFW AXBDeploy Fault, IPDR RFA #26
  • Single String Mission
  • Credible AXB deployment failure mechanisms which might result in an unintended or over-long deployment and mitigations:

RBSP/EFW CDR 2009 9/30-10/1

efw axb worst case fault
EFW AXBWorst 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.

RBSP/EFW CDR 2009 9/30-10/1

efw axb tube
EFW AXBTube
  • Structural Design
    • Fixed-Fixed First Frequency: 257 Hz
    • Tube Static Stress Margin: 10
    • Buckling Force: 3600 lbs (max load: 1200 lbs)

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description booms2
EFW AXBDesign Description: Booms

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description booms3
EFW AXBDesign 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
      • (> 4x SC Spin Rate  Rigid)

Preamp

Hinge

Whip

Sphere

Deployed Configuration

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description i t
EFW AXBDesign Description: I&T
  • ETU Flow: Stiffness Testing
    • Slope: 0.003 lb/in

inches

grams

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description i t1
EFW AXBDesign 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.

RBSP/EFW CDR 2009 9/30-10/1

efw axb design description i t2
EFW AXBDesign 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

RBSP/EFW CDR 2009 9/30-10/1

efw axb mate demate tally
EFW AXBMate / Demate Tally

RBSP/EFW CDR 2009 9/30-10/1

efw axb blind mates
EFW AXBBlind 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

RBSP/EFW CDR 2009 9/30-10/1

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RBSP/EFW CDR 2009 9/30-10/1

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