Preliminary Design ReviewNovember 19, 2012

GOTHAM Boom

Outline

● Introductions● Project Goals● Requirements● Previous Work● Structures● Testing ● EECS

Team Structure

Long-Term Project Goals

● Increase TRL of current boom design from a 3 to a 6● Develop a deployable, space environment qualified,

and non-ferric boom that fits within a 1U CubeSat● Support Sensors up to 5 x 5 x 6cm and at least 500g● Mission Opportunities

○ GOTHAM: Hold 500g magnetometer away from the electromagnetic noise of the CubeSat electronics

● Other Possible Applications:○ Gravity gradient stabilization○ Sensors that need to minimize noise from electronics

Short-Term Project Goals

● Manufacture prototype using engineering model stacer

● Create boom tip detection system● Test prototype

○ System ID○ TVC○ Vibe○ Microgravity Flight

GOTHAM Mission

■ GOTHAM – GPS Occultation Tomographer & High Accuracy Magnetometer

● 3U CubeSat● Boom

● Hold magnetometer away from electromagnetic noise generated by CubeSat

● Magnetometer● Measure magnetic field-aligned

currents in the ionosphere● Measure ultra-low frequency

waves in the ionosphere

Requirements

Useable Volume

Requirements3.2.1.1.1 The system mass shall be no greater than 1.0 kg, not including payload. Boom Team

3.2.1.1.3 The system shall deploy a payload of 0.5kg Dr. Mark Moldwin

3.2.1.1.3 Space debris shall not be generated by the boom system. CalPoly CDS

3.2.1.2.1 The system shall be entirely contained within an 8.30 x 8.30 x 10.00 cm volume when in stowed configuration. Boom Team

3.2.1.2.2 The system shall allow for a 5.00 x 6.00 x 5.00 cm payload bay. Dr. Mark Moldwin

3.2.1.2.3 The system shall provide for stowage of a wiring harness for connection to the end of the (deployed) boom such that the minimum bend radius is greater than 2.86 cm.

Dr. Mark Moldwin

3.2.1.2.4 In stowed configuration the system center of mass shall be located within a sphere of 2 cm diameter from the system geometric center, payload not included. Boom Team

3.2.1.3.1 The system shall deploy such that the closest face of the supported payload is at least 25.0 cm from the +Z end of the satellite structure.

Dr. Mark Moldwin

3.2.1.3.2 The system shall deploy a wiring harness for connection to the payload. Dr. Mark Moldwin

3.2.2.1.1 The stowed system shall withstand vibration testing as specified by NASA General Environmental Verification Standard, document GSFC-STD-7000, and CalPoly DSCR. CalPoly CDS

3.2.2.1.2 The stowed system, including 0.5kg payload, shall have a first-mode resonant frequency greater than 150Hz. Boom Team

3.2.2.1.4 The stowed system shall pass thermal vacuum chamber test requirements as specified by CalPoly CDS and DSCR. CalPoly CDS

3.2.2.1.5 The payload mounting platform shall be held by a constant force great enough to prevent separation from the corresponding stop during vibration and shock testing. Boom Team

3.2.2.1.6 The system shall be able to maintain the stowed configuration for a minimum of 90 days without degradation of performance. Boom Team

Requirements

3.2.2.2.1 The system shall deploy a payload mass of 0.5kg from a CubeSat of at least 4.5 kg. Dr. Mark Moldwin

3.2.2.2.2 The system shall have knowledge of the exact position of the boom, in the deployed state to within 1 degree. Dr. Mark

Moldwin

3.2.2.2.3 Including a 0.5kg payload the deployed boom shall have a first-mode resonant frequency greater than 1Hz. Boom Team

3.2.2.2.4 The deployed boom shall have a flexural rigidity greater than 400 N-m2. Boom Team

3.2.2.2.5 The deployed boom shall be retractable by manual means only. Boom Team

3.2.2.2.6 The minimum mission duration shall be no less than 18 months. Boom Team

3.2.3.1.1 Under no circumstances typical of the pre-launch, launch, CubeSat pre-deployment and Cubesat deployment +30 minute environments, as simulated by conditions specified by the CalPoly DSCR, shall the boom deploy without operator intention.

Boom Team

3.2.3.1.2 The stowed configuration shall be verified by an electrical sensor. Dr. Mark Moldwin

3.2.3.2.1 Deployment mechanisms shall feature singly redundant operation. Boom Team

3.2.3.2.2 The system shall be able to deploy a minimum of 10 times without degradation of performance. Boom Team

3.2.3.3.1 Achievement of deployed configuration shall be verified by an electrical sensor. Dr. Mark Moldwin

3.2.3.3.2 The deployed state shall be maintained by singly redundant means. Boom Team

3.2.4.1.1 The system shall be designed for operations within LEO, near and deep space. Dr. Mark Moldwin

3.3.1.1.1 Materials shall be NASA or LSP approved. CalPoly CDS

3.3.2.1.1 No ferric materials shall be used in the construction of the boom or payload mounting platform.

Dr. Mark Moldwin

Requirements

3.3.3.1.1 The system shall be designed for integration with any standard CubeSat by means of a 4 x #4-40 bolt pattern. Boom Team

3.3.4.1.1 NIST-traceable torque wrench use shall be mandatory for assembly of qualification and flight hardware. Boom Team

3.3.4.1.2 All fasteners which do not have integral secondary locking features shall be staked according to AIAA S-110-2005. Boom Team

3.3.4.1.3 All electrical connections external to purchased components shall be made according to NASA-STD-8739.1A. Boom Team

3.3.4.1.4 All qualification and flight components shall be cleaned by means compatible with their constituent materials prior to assembly. Boom Team

3.3.4.1.5 Final assembly of qualification and flight components shall occur on electrostatic dissipative surfaces. Boom Team

4.1.1.1.1 All engineering drawings shall be maintained such that any revisions after the PDR are approved and dated by the chief engineer, and include a written summary of change. Boom Team

4.1.1.1.2 Documentation shall be developed which describes assembly procedures and specifications and records conformance thereto during all qualification and flight unit assembly.

Boom Team

4.1.1.1.3 All qualification and flight components and assemblies shall be inspected for conformance to approved engineering drawings. Boom Team

4.1.1.1.4 Product conformance inspection documentation shall be maintained for all qualification and flight parts and assemblies, conforming and non-conforming. Boom Team

4.1.1.1.5 Reports regarding non-conforming parts and assemblies shall be generated which outline causes of non-conformance and propose process or design revisions. Boom Team

4.1.1.1.6 A set of engineering drawings shall be annotated with the actual measured dimensions for all qualification and flight components and assemblies. Boom Team

Requirements

4.2.1.1.1 Functionality testing shall verify the system ability to deploy and remain deployed in a manner such that all performance requirements and/or specifications are met and/or maintained.

Boom Team

4.2.1.1.2 Functionality testing shall occur following each qualification test, for each flight unit upon completion of final assembly, and following integration with customer satellites.

Boom Team

4.2.1.1.3

Functionality testing shall include but not be limited to: Single deployment event under simulated payload and microgravity conditions, Visual inspection of fastener and other staking, Inspection of mechanical integrity and dimensional stability, Visual inspection of electrical system, Evaluation of deployment mechanism electrical performance.

Boom Team

4.2.1.1.4 Documentation shall be developed which describes functionality test procedures, records conformance thereto for all qualification and flight hardware, and presents results thereof.

Boom Team

4.2.2.1.1 Stowed configuration vibration testing shall be performed by the University of Michigan SPRL. Boom Team

4.2.2.1.2 Documentation shall be developed which describes vibration testing procedures and specifications, records conformance thereto, and presents results thereof for all qualification and flight hardware.

Boom Team

4.2.3.1.1 Shock testing shall be performed by the GOTHAM Boom team such that it complies with NASA GSFC-STD-7000. CalPoly CDS

4.2.4.1.1 The profile specified by CalPoly DSCR shall be used for thermal bake-out. Boom Team

4.2.4.1.2 After undergoing thermal bakeout the Total Mass Loss shall be ≤ 1.0% CalPoly DSCR

4.2.4.1.3 After undergoing thermal bakeout the Collected Volatile Condensable Material shall be ≤ 0.1% CalPoly DSCR

4.2.4.1.4 Functionality shall be tested at minimum conditions specified by CalPoly DSCR. Boom Team

4.2.4.1.5 Documentation shall be developed which describes thermal and vacuum testing procedures and specifications, records conformance thereto, and presents results thereof for all qualification and flight hardware.

Boom Team

4.2.5.1.1A method for degaussing flight assemblies shall be developed for application prior to assembly electromagnetic field identification, and prior to integration with customer satellites.

Requirements

4.2.5.1.2 The electromagnetic field properties of the system in both deployed and stowed configuration shall be identified such that boom deployment state can be determined.

Dr. Mark Moldwin

4.2.5.1.3 Documentation shall be developed which describes electromagnetic test procedures and specifications, records conformance thereto, and presents results thereof for all qualification and flight hardware.

Boom Team

4.2.6.1.1 Proof and ultimate load ratings shall be estimated based on mathematical modeling and test data unless otherwise requested by special customer contract. Boom Team

4.2.7.1.1

System identification testing and/or simulation shall determine the following characteristics of the deployed configuration: Damping ratio in torsion and bending, Damped Frequency in torsion and bending, Harmonic frequencies in torsion and bending, Center of mass, Moments of inertia about 3 axes.

Boom Team

4.3.1.1.1 Transport containers shall be used which isolate flight or qualification hardware from effects typical of the foot or passenger car environment. Boom Team

4.3.2.1.1 Flight and qualification hardware shall be stored in the fully assembled, deployed state without payload integration. Boom Team

4.3.2.1.2 Storage units which limit dust, humidity, and electrostatic buildup shall be utilized for long-term storage. Boom Team

4.3.2.1.3 Separate storage units shall exist for each flight system. Boom Team

4.3.2.1.4 Storage units shall be kept within the University of Michigan Space Research Building.

4.3.3.1.1 Entities external to the University of Michigan who purchase flight systems shall be independently responsible for development of integration procedures and are allowed access to GOTHAM Boom assembly procedure documentation.

Boom Team

4.3.3.1.2

Entities external to the University of Michigan who purchase flight systems and have performed final integration shall be independently responsible for verification of system operation, and are allowed access to GOTHAM Boom team data for performance baseline.

Boom Team

4.3.3.1.3 Entities external to the University of Michigan who purchase flight systems and have completed flight hardware integration shall provide for the off-campus transport of systems.

Boom Team

Previous Work

Coilable Boom

Telescoping

● 5-segment Telescoping Boom○ Deployed via stacer spring○ Released using a pinpuller

Structures/Testing

Sally SmithMeghan Diehl

Christopher ReynoldsWalker Woodworth

Outline

● General Design○ Workspace-Cubesat

● Extendable Boom○ Custom stacer

● Mounting Hardware○ Baseplate○ Magnetometer mount

● Retention/Actuation○ Burn circuit

● ANSYS FEA Analysis● Future Work

General Design

■ Stacer based

■ Location determined by camera

■ Cable wrapped around Magnetometer

■ Burn circuit release

■ Extends up to 1m

3U Cubesat Frame

● Dimensions: 10 cm x 10 cm x 30 cm○ (3.9 in x 3.9 in x 11.8 in)

● Material: Aluminum 6061● Contains the electronics and extendable boom

system● Free-floating part of experiment● Referred to as payload when also including boom

and electronics

Extendable Boom

● Main focus of experiment● Extends 12.48 in (31.7 cm) telescopically from the

payload● Designed to carry a magnetometer (but will have

strain gauges and IMUs for testing?)● Stacer designed by Hunter Spring

Stacer

■ Stacer from AMTEK Hunter Springs

■ Non-ferrous■ Elegeloy, BeCu, Stainless Steel, or Havlor

■ Up to 2" diameter with 1.5" height

■ Deployed length of 30cm

■ Custom made■ Expensive (~$15,000)

■ 8-12 weeks from order to delivery

■ Attached to design by rivets

■ 1 rivet in tip

■ Up to 5 in base

Base Structure

■ Designed to house stacer in

compressed form■ Stacer base attached to inner

cylinder by rivets

■ Attachment will be done by

Hunter Spring

■ Contains rubber O-Ring to

help stabilize structure

during vibration.■ Junction of mount seat and

mount

Magnetometer Mount

■ Fits into base structure

■ Sits on top of rubber O-ring

■ Attached to stacer tip

■ Aluminum cable attached with set screw

■ Contains mounting points for magnetometer

Retention System

■ Dual material system: aluminum wire and burnable cable■ Easier to replace burn circuit between tests

■ Aluminum wire■ Attached to magnetometer mount with set screw

■ Feeds through stacer to below base plate

■ Crimped for attachment to burnable cable

■ 0.025" diameter, rated to 200 deg F

■ Burnable cable■ Considering three types of high-strength braided fishing

line

■ Attached to crimped loop in aluminum wire

■ Attached to base plate with set screw

Retention System

Magnetometer mount with aluminum cable and set screw

Aluminum Wire Selection

Goals: 1. Prevent Spring from Releasing

2. Smallest Possible Wire

3. Maintain Decent Factor of Safety

Choice: D = 0.025 in, Al Alloy 1100

Reasoning:

- Forces: 3 N (static from spring) and 10 N (shock from launch)

- Tensile Strength = 105 MPa

- Wire has A = 0.00196 sq in

- Factor of Safety = 10

Burn Circuit Release Mechanism

■ Nichrome wire heating element

■ Single point release system

■ Multiple release points difficult to coordinate

■ Redundancy not necessary for design

■ Nichrome heats up, burning through cable and

releasing boom

■ Burn circuit may need to be placed on top of base

plate because of space constraints

■ Possible issue with stress on fishing line

Release Mechanism

■ Nichrome wire (.036", .025", .016")

■ Melting parameters for a 4.65 Ohm/ft 2 cm

nichrome wire in contact with plastic (3 coils)

■ Tests will be conducted on three diameters with 3

coils for low power usage

Voltage Amperage Effect

1 Volt 0.2 Amps Plastic melts

2.6 Volt 0.5 Amps Nichrome glueing

4.5 Volt 0.8 Amps Nichrome melts

Rivets

● Connect stacer to mount & baseplate● 4 rivets in base, 1 rivet at the top for mount● Riveting will be done by Hunter Springs, we will

send our parts● One design issue was having enough space in the

mount seat for Hunter Springs to fit their tools in to rivet

Mechanical Payload Mass Budget

Item Quantity Mass (g) Each Contingency Total Mass (g)

Set Screw 2 0.06 10% 0.2

Magnetometer Mount 1 24.25 15% 27.9

Mount Seat 1 55.62 15% 63.9

Magnetometer 1 500 10% 550

O-ring 1 2.3 10% 2.5

Stacer Spring 1 26 10% 28.6

Nichrome Wire 1 0.01 15% 0.1

Aluminum Wire 1 0.05 15% 0.1

Fishing Line 1 0.05 15% 0.1

Base Plate 1 81 10% 89.1

TOTAL MASS 762.5 g

Item Manufacturer Cost ($) Each Contigency Total Cost ($)

Set Screw McMasters $0.20 10% $0.66

Magnetometer Mount In-house $6 10% $6.60

Mount Seat In-house $12 10% $13.20

Base Plate In-house $5 10% $5.50

O-ring McMaster $5 10% $5.50

Stacer Spring Hunter Spring $15,000 10% $16,500

Nichrome Wire McMaster $1.10 10% $1.21

Aluminum Wire McMaster $0.05 10% $0.06

Fishing Line Spiderwire $0.05 10% $0.06

TOTAL COST $16,527

Mechanical Payload Cost Budget

Structural Testing

ANSYS Finite Element Analysis

Acceleration Testing

● Analyze acceleration up to 20 times the force of gravity in two directions (up/down, left/right)

● Upward/downward acceleration● Factor of safety: 86.41

Acceleration Testing

● Right/left acceleration effects● Factor of safety:41.47

Retention System Testing

● Force acting down on wire with acceleration of 20 times gravity upward

● Aluminum wire of diameter .025" withstands test with factor of safety of 6

Future Structures Work

● Test burn circuit ○ Optimize power level, burn time, configuration○ Determine best fishing line

● Test retention system and burn circuit○ Use mass representatives

● Build new mount, mount seat - new designs● Complete building both systems (test stacer used

for redundancy)○ Send to Hunter Springs for attachment

● Complete vibration testing platform● Testing

○ Vibration, thermal, vacuum

EECS

Leif MillarKarl Gendler

Maxime Lawton

Position Determination

■Scale sample rate■Exact algorithm / rate TBD

■Possibly add flash use decision

■Possibly add bad image handling■LED failure■Camera failure■Tape degradation

Camera

● OVM 7690 ● 11.2 pixels/degree at 1m● Active: 100mW + ~ 100mW LED● Standby: 20 uA = 0.034mW● 960 mV/Lux-sec: need a light source● At an average sampling rate of 30 Hz

○ 5.120 kB/s○ 0.145 mW average

Flash - LED

■Charge M’s markings■120mW

■Operational temperature -40°C to 80°C

■Small space needs

“M” Design as Reference

■Gauge rotation in space■Non-invertible■Symmetrical

■Compare against reference

■Luminescent tape

■Located under mag plate

Power Budget

■ Typical 1U: 2.7W Orbital Average (at launch, 2.0 W after ~5 years)■ 8 Panels on our section => 2.0W * (2/3) = 4/3W

■ Processor: TI MSP430■ 500nA @ 3V = 1.5mW■ Additional components will be needed.

■ LED■ 3.2V forward voltage,■ 120 mW power dissipation

■ Camera■2.6 - 3.0 V ■100mW active, ~60µW standby

■ Magnetometer■ Responsible for ~1/3 of 500mW

Total = 388mW + components

Detecting the M

● Phosphorescent gaff tape● Withstands up to 200°F● Glows 4-8 hours after 3-10 second exposure● ~21 lux after 10 minutes, ~4 lux after 60 minutes

● Coat with protective adhesive to prevent degradation under UV light

● Concerns about off-gassing and life span of protectant products

● Detect sun to avoid camera damage● Photoresistors/diodes vs Coarse sun sensors● Coarse sun sensors

● draw no power● expensive

● very large and heavy (56 cm2, 60g)

● Photoresistors/diodes● draw power● inexpensive ● very light and versatile● minimize power draw -> high dark resistance

Detecting the Sun

Thank You!!

● Contact○ Garrett Cullen: gmcullen@umich.edu○ Josh Lipshaw: lipsjosh@umich.edu