1613-4 Sept. 2008EFW INST+SOC PDR EFW AXB Jeremy McCauley Aerospace Engineer Space Sciences Laboratory, UCB [email protected] AXB Spacecraft +Z

1 3-4 Sept. 2008 EFW INST+SOC PDR

EFW AXB

Jeremy McCauleyAerospace EngineerSpace Sciences Laboratory, [email protected]

AXB

AXB

Spacecraft +Z


EFW AXB Overview

• Design Drivers• Design Description

– Concept

– Heritage

– Assembly Breakout

– Thermal

• ETU Integration and Testing (I&T)• MGSE Requirements• Ongoing Developments


EFW AXB Design Drivers

• Deploy spherical electric fields probes up to 6 meters with an E-Field sensor 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 (< 3” radial).• 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)


EFW AXB Design Description: Concept

• Axial Boom Unit (AXB)– Sensors Extended from SC on Stacers

• Compact for Launch

• Rigid after Deploy

• Adjustable Length

Upper Boom Unit (+Z)

Lower Boom Unit (-Z)


EFW AXB Design Description: 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 POLAR and FAST

– 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


EFW AXB Design Description: Order of Deploy

Stowed Unit

•Unpowered

•Fully RestrainedStep 1: Whip Deploy

•Frangibolt Actuated

•Spring Powered

Step 2: Stacer Deploy

•Frangibolt Release

•Motor Driven (1.2 cm/s)

•Length Adjustable

+Z SC Axis


EFW AXB Design Description: AXB

• Structural Design– End Supported Tube with Aluminum End Fittings– Two (2) Identical Boom Units

• Stationary Deploy Assy• Moving DAD• Stacer• Whip and Spherical Electric Fields Probe

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]


EFW AXB Design Description: Tube

• Structural Design– End Supported Tube: Graphite Epoxy,

M55 (Layup: 0, 45, 90, 45, 0 [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

– Static and Vibration testing as specified

– Joint Epoxy: Hysol 9309NA

– Bond Shear Stress Margin: 30.3

Tube

End Fitting

Flexure

Flexure atdT=52ºC


EFW AXB Design Description: Booms

• Boom Design– Stationary

Deploy Assy– Moving DAD– Stacer– Whip and Spherical Electric

Fields Probe

Whip

DAD

Stacer

Deploy Assy

Stowed Configuration

Deployed Configuration



• Stationary Deploy Assy– Sphere Caging Mechanism

– Direct Drive Assembly

– Roller Nozzle #1

Sphere CagingMechanism

Roller Nozzle #1

Direct Drive Assy





• 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

AC Test Contact

Enable Plug

Frangibolt


EFW AXB Design Description: Frangibolt

• Frangibolt– 500 lb Retention Force

• For Launch Loads Only

– Resettable

– 25 W @ 28 Vdc

– Actuation Time: < 10 s

http://tiniaerospace.com/fbt/fbfc2-16-31sr2.html



• Direct Drive Assembly– Stacer Frangibolt Release– Harness Spool: Max Capacity 9.2 meters 0.085” diameter cable– Motor Drive Mechanism: SPB motor (1000:1 gear ratio)– Sense Switches: Frangibolt Release, End of Travel and Turn Counter– Slip Ring– Length Resolution: 0.78 cm/click BOT, 0.53 cm/click EOT, 2.4 clicks/s– Torque Margin: 7.6 (Motor Torque to Torque to Retract Stacer)

Frangibolt

Sense Switches Spool

Harness

Motor Slip Ring



• Roller Nozzle #1– Centering of the Stacer– Resist SC Forces

Rollers

Rocker Arms



• 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– Force Margin: 2.1

• DAD Springs to Friction

Stowed Configuration Deployed Configuration

DAD Springs

Lock Wheel Assy

Roller Nozzle #2



• Stacer– Helical Spring– Deployed Acts as a Rigid Tube

• Spin Adjusted Resonance: 26.5 RPM

– Force Margin: > 3 • Stacer Force to Friction

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



• 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)

StowedConfiguration


SphereInternal View

Whip

Sphere

HingePreamp


EFW AXB Design Description: Thermal (TBC)

• Thermally Coupled to the SC

• Spherical Electric Fields Probe, Whip and Hinge:

– Coated with DAG 213

• Stacer:

– Mill Finish Elgiloy

• Moving DAD:

– Alodine (Gold)

– Taped with Germanium Black Kapton

– Electroless Nickel Plating with Teflon Impregnate

• Stationary Deploy Assy:

– Alodine (Gold)

– Electroless Nickel Plating with Teflon Impregnate

• End Supported Tube

– M55 Graphite Epoxy

• Aluminum End Fittings

– Alodine (Gold)


EFW AXB Design Description: I&T



• ETU Flow: DDD Testing– Connectors need testing for Deep Dielectric Discharge (DDD)

– Not reasonable on a part by part basis

– Harness will be tested in unit, prior to Preamp installation

Sphere

Whip Hinge

Whip Harness



• ETU Flow: Deployments– Expected number of deployments on the instrument at launch: 4

• Length and Fundamental Frequency Test

• Alignment and Runout Test

• Thermal Vacuum Hot

• Thermal Vacuum Cold

• Deployments at Instrument and SC Level

will be by means of

Frangibolt simulators only



• ETU Flow: Length and Fundamental Frequency Testing– Unit will be deployed horizontally on a g-negating track, then suspended

vertically for fundamental frequency data.

• Gravitational component will be subtracted from frequency.

– Wire EOT switch test

– Motor, Frangibolt current profile



• ETU Flow: Alignment and Stiffness Testing– Requirement: 3 inches radial at Sphere– RSS Analysis of Stationary Deploy Assy and Moving DAD Tolerance

Stackup: • 0.20 degree (0.8 inches)

– Stacer Runout is not accounted for– Hinge, Whip and Sphere Runout is TBD– Unit will be deployed horizontally on a g-negating track, then lifted to

floats for g-negated runout and stiffness measurements. (POLAR)



• ETU Flow: Vibration Testing– Vibration (modal survey, sine, and random) to Qualification levels per

7417-9019 Section 5.4.5 at the Component level (IDPU, SPB, AXB)

– Self-shock survival from boom deployments actuations shall be demonstrated at the component level (SPB and AXB) by at least 2 actuations (only the initial release generates a shock)

– Post-vibration deployments during Thermal Vacuum testing



• ETU Flow: Thermal Vacuum Testing– 6 operational cycles plus 1 survival cycle, per the requirements and limits

indicated in 7417-9019 section 5.3.2– Deployment tests will be performed at hot and cold levels – Whip and Caging Mechanism deployment testing performed at the

subassembly level– Stacer deployment performed at the assembly level

• Unit will be deployed horizontally on a g-negating track within the Thermal Vacuum Chamber

– Preamplifiers will be separately tested.


EFW AXB Design Description: MGSE

• MGSE Required:– Whip Offload Fixture

• Deployment testing of hinge, whip and sphere in air and at vacuum• Requires design and fabrication

– Horizontal Deployment Track:• Deployment testing of Stacer in air and at vacuum• Requires adaptation of SWAVES Track for form factor

– Runout Fixture:• G-negated runout measurements of the deployed antenna• Requires fabrication of float system and rotational fixtures

– Vibe Fixture:• Vibration Testing of Boom Unit with Whip, Sphere and Caging

Assembly• Requires design and fabrication

– Shipping Container:• I&T Travel Protection• Requires adaptation of THEMIS or STEREO IMPACT Cases


EFW AXB Ongoing Developments

• Motor Driven Deployment of a Stacer– EM Deployment Testing Successful

• Harnessing the Whip– EM Harness and Braid successfully built for Hinge Testing


EFW AXB Design Description

• Back up slides– Redundancy is Key….



ID Req. TitlePriorit

yRequirement Body or Section Heading

3 Functional Requirements

3.1 Functional, performance and general design requirements

EFW-1 Instrument Design life shall be designed for a total lifetime duration of 2 years plus 60 days.

EFW-200 Instrument Calibration shallbe calibrated prior to launch, and be designed to accommodate additional in-flight calibration

EFW-6 Instrument Orbit Inclination Operability shall be capable of operating in an orbit with an inclination of 10° ± 0.25°.

EFW-7 Instrument Orbit Perigee Operability shallbe capable of operating in an orbit where perigee altitude is between 500 km and 675 km (TBR).

EFW-8 Instrument Orbit Apogee Operability shallbe capable of operating in an orbit where apogee altitude is between 30,050 km and 31,250 km (TBR).

EFW-201Instrument Accommodation of Observatory Sun Off-Point Angle (Component)

shall

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 relative to the Earth orbit plane, where "north" and "south" are with respect to an ecliptic coordinate system.

EFW-202Instrument 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-9Instrument Accommodation of Observatory Operational Spin Rate Range

shallbe capable of operating nominally within an observatory spin rate range of no less than 4 rpm and no more than 6 rpm.

EFW-10Instrument Accommodation of Observatory Selected Operational Spin Rate

shallbe capable of collecting required science measurements at a specific, optimal spin rate selected for both observatories that is within the specified allowable range







EFW-11Instrument Accommodation of Observatory Selected Spin Rate Stability

shallbe 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.

EFW-203Instrument Accommodation of Unattended Mission Operations

shallbe capable of accommodating an observatory spin rate during commissioning period activities within a range between 3 RPM (TBR) and 15 RPM (TBR).

EFW-12Instrument Accommodation of Unattended Mission Operations

shallbe 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 shallconsist 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-22Functionally Identical EFW Instrument Suites

shallbe functionally identical.

EFW-23 EFW - Spacecraft ICD Compliance shall comply with the EFW-to-Spacecraft interface control documents (ICDs).

EFW-24 EFW Instrument Availability shallbe 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-209EFW Spin Axis Measurement Sensitivity Validity

shallmeet 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.







EFW-51Measure 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 - 500 mV/m; -- cadence: 32 vectors/second; -- sensitivity: 4 mV/m or 20% for R > 3.5 Re, 6 mV/m or 20% for 3.5 Re > R > 2.5 Re, 12 mV/m or 20% for R < 2.5 Re.

EFW-52 Measure Spin Axis DC Electric Field (Burst) shall

measure axial electric field components (burst), as follows: -- frequency range: DC to 256 Hz; -- magnitude range: 0.4 - 500 mV/m; -- cadence: 512 samples per second; -- sensitivity: 1 mV/m or 10% @ 50 Hz (TBR).

Required Components to Achieve Above

EFW-54 EFW Axial E-Field Booms shallbe capable of deploying 6 meters with an E-Field sensor preamp at the end capable of measuring E-Fields to 400 kHz

EFW-54a EFW Axial E-Field Booms shallDeploy the AXB sensors within +/- 1 degree of the AXB deployment system axis

EFW-56 EFW Harnessing shallconnect the SPB, AXB, IDPU, EMFISIS/MAG and EMFISIS/SCM units together as detailed in the ICDs

EFW-61 EFW Power Control shall 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 shalltolerate without damage a maximum input voltage of 40V indefinitely as defined in the ICD

EFW-66 EFW Main Power Turn Off shalltolerate without damage having power removed without notice as defined in the ICD

EFW-68 EFW AXB Deployment Power shall not exceed 4.0 Amps from the EFW AXB Deployment Service

EFW-69 EFW Survival Heaters shallaccommodate survival heaters up to 1/2 nominal power at 22V bus voltage, or approximately 113 Ohms.

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 shall not exceed 2.0 Amps at 28V

EFW-74 EFW AXB Motor Power shall not exceed 0.2 Amps at 28V (1.5A startup)

3.4 Operational requirements

EFW-77 EFW AXB Operational Temp Range shall perform as designed from -25 to +55C (TBR)

EFW-80 EFW AXB Survival Temp Range shall survive without damage from -30 to +60C (TBR)

3.6 Interfaces to the spacecraft bus

EFW-90 EFW AXB ICD Compliance shallcomply 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 shallprovide a connector for test input to the sensor accessible when the top and bottom of the spacecraft are accessible.






3.10 Fault detection and correction considerations/requirements

EFW-100 EFW AXB Deployment Enable shallnot deploy AXB booms or fire AXB actuators without the AXB and Main power ON.

3.11 Redundancy description

EFW-101 EFW Boom Pair Redundancy shall be capable of powering each E field axis separately.

EFW-102 EFW Safing by subsystem shallseparately 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 shallThe 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 shall not exceed 3.64 kg

EFW-107 EFW AXB Tube Mass shall not exceed 1.29 kg

EFW-108 EFW Harness Mass shall not exceed 2.50 kg (TBR)

3.15 Contamination control requirements

EFW-132Instrument Compliance with Contamination Control Plan

shallcomply with the requirements and constraints imposed by the RBSP Observatory Contamination Control Plan, APL document no. 7417-9007

EFW-133Instrument Compliance with EM Environment Control Plan

shallcomply with the requirements and constraints imposed by the RBSP Electromagnetic Environment Control Plan, APL document no. 7417-9018.

EFW-135 EFW ESC Control shall comply with the UCB Electrostatic Cleanliness (ESC) Plan






3.15 Contamination control requirements

EFW-136Instrument Compliance with Environmental Design and Test Requirements Document

shallcomply with the requirements and constraints imposed by the RBSP Environmental Design and Test Requirements Document, APL document no. 7417-9019.

EFW-137 EFW Quality Assurance shallcomply with the RBSP Performance Assurance Implementation Plan, as modified by the Compliance Matrix

EFW-210Instrument Compliance with Space Asset Protection

shallshall comply with requirements imposed by [document ref. TBD], RBSP Space Asset Protection Plan

EFW-211Instrument Compliance with Safety Program Plan

shallcomply with requirements imposed by [APL document ref. TBD], RBSP System Safety Program Plan

EFW-212 Observatory Naming Convention shall

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.


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).

Factor of Safety (FOS)Type

STATIC

SINE

R / AA CN OD UO SM T I C

Metallic Yield 1.3 1.3 1.6

Metallic Ultimate 1.4 1.4 1.8

Stability Ultimate 1.4 1.4 1.8

Composite Ultimate 1.5 1.5 1.9

Bonded Inserts/JointsUltimate

1.5 1.5 1.9


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• Tantalum per ASTM-B365-98, 65 kpsi (Ultimate)• Titanium, 6Al-4V, 120 kpsi



• 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



• 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



• 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


EFW AXB Design Description: Stress Margins

Critical Part Stress Margin

Stacer Frangibolt 14

Mounting Flexure 0.6

Mounting Flange 2.7

Mounting Tube 10

Tube Bond (Top) 30

Whip Tube 128

Whip Hinge Pin 34


EFW AXB Design Description: Tube

• Structural Design– End Supported Tube: Graphite

Epoxy, M55 (Layup: 0, 45, 90, 45, 0 [quasi-isotropic])

– Fixed-Fixed First Frequency: 257 Hz


RBSP AXB Stacer Deploy Force Ratio

0

1

2

3

4

5

6

7

8

9

10

11

12

0 2 4 6 8 10 12 14 16 18 20

Deployed Length (ft)

Force RatioPush Force (lb)Nozzle Drag (lb)

Push Force (lb) Nozzle Drag (lb) Req'd Ratio Force Ratio




• 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)

StowedConfiguration


Whip

Sphere

HingePreamp

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 10 20 30 40 50 60 70 80 90

T-Spring (lb-in)

T-Measured (lb-in)

T-Required (lb-in)


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Documents

1613-4 Sept. 2008EFW INST+SOC PDR EFW AXB Jeremy McCauley Aerospace Engineer Space Sciences Laboratory, UCB [email protected] AXB Spacecraft +Z