cinema pdr- mec 1 cinema mechanical subsystem pdr august 22, 2008 david glaser/paul turin

CINEMA PDR- MEC1

CINEMA Mechanical Subsystem

PDR August 22, 2008David Glaser/Paul Turin

CINEMA PDR- MEC2

MECHANICAL -- Overview

•Mechanical Requirements

•Mechanical Subsystems

• Chassis

• Solar Array

• Communication Hardware

• Torque Coils

• Sun Sensor

• Magnetometer Boom

• STEIN

• Mass Budget

CINEMA PDR- MEC3

MECHANICAL – Requirements

•Meet Cubesat Interface and Mass Specifications

•Withstand Launch Environmental Loads

•Keep Internal Magnetic Field to a Minimum

•Design

•Bus Chassis

•House All Components in Bus

•STEIN Instrument Attenuating Shutter

•Magnetometer Boom Deployment Mechanism

•Magnetometer Harness

•Harnessing (TBD)

CINEMA PDR- MEC4

MECHANICAL – CubeSat Req.

1. CINEMA must fit inside a P-Pod (Poly-Picosatellite Orbit Deployer) and be deployed without jamming

2. No parts may separate from the satellite (no space debris created)

3. No pyrotechnics allowed4. Maximum Mass: 3 kg

(negotiable?)5. Kill Switch, Deployment Switch,

and Spring Plungers

P-POD CAD Image http://cubesat.atl.calpoly.edu/pages/reference/pictures.php

KC-135 P-POD Test Videohttp://cubesat.atl.calpoly.edu/pages/reference/videos.php

CINEMA PDR- MEC5

MECHANICAL -- Chassis

•0.050 inch thick Aluminum Sheet Metal•Ends – ¼ inch Aluminum•Rail Dimensions to Cubesat Specifications

340.5 mm

100 mm

100

mm

Rails HardAnodized

CINEMA PDR- MEC6

MECHANICAL -- Chassis

DeploymentSwitch

SpringPlunger

SpringPlunger

CINEMA PDR- MEC7

MECHANICAL -- Overview

ScienceRadio

Transmitter

GenesatAvionics

Box MagBoom

Deployer

Outboard Magnetometer

Sun Sensors

STEIN

Components will generally be fastened with a #4-40 flathead screw, countersunk into chassis.

InboardMagnetometer

CINEMA PDR- MEC8

MECHANICAL – Solar Array

• 10 Panels (3 on each long side 1 Panel on top, bottom, and short sides)

• Each Panel 3 x 3.2 inches (7.6 x 8.1 cm)

•Nominal Bus Voltage is 9.2 V• Therefore need 4x PV cells on each panel• Typical cells too large• TASC cells are small enough, but require assembly, and have

no coverglass

CINEMA PDR- MEC9

MECHANICAL – Solar Array

1.55 cm(.61 inches)

3.18 cm (1.25 inches)

TASC PV Cells (Spectrolab)

•20 Cells/Panel•8 Panels•Cost of Cells: $500•No Coverglass Included•Cost of Assembly ?

CINEMA PDR- MEC10

MECHANICAL - Communication

Patch Antennas

•Science Data Transmitter•Telemetry Transceiver•2 Science Data Patch Antennas•2 Telemetry Patch Antennas

CINEMA PDR- MEC11

MECHANICAL – Torque Coils

Coils located onSTEIN Side andBottom

Torque Coil Rail

CINEMA PDR- MEC12

MECHANICAL – Torque Coils

• 28 AWG Magnet Wire (0.32 mm diam./ max current 1.4 A)

• 62 Turns (50 m of wire)

• Coil Length: 0.317 m Width: 0.086 m

• Effective Coil Area: 0.0256 m2

• Electrical Resistance: 10.65Ω

Bus Voltage Current (A) Am2

Power (W)

7.5 0.70 1.16 5.28

9.2 0.86 1.42 7.94

CINEMA PDR- MEC13

MECHANICAL – Sun Sensors

• Field of View Per Sensor: 5° Azimuth x 41° Elevation

• 2 Sensors @ 45° to Vertical, 90° to Each Other

• Sensor: Phototransistor (Motorola MRD300)

• Prototype Tested

•Load Resistor: 1 kΩ

• Vcc = 5 V

•Power: ~25 mW (Light); ~10µW (Dark)

1.6 cm

2.3

cm

CINEMA PDR- MEC14

MECHANICAL – Sun Sensors

Horizontal Sweep 1 RPM

-1

0

1

2

3

4

5

6

0.00 0.50 1.00 1.50 2.00

Time (sec)

Sen

sor

Vo

ltag

e (V

)

Test 1

Test 2

Test 3

Test 4

Reflection from White Paper

4.6° > 1 Volt

Rise Time ~120 ms

Simulation ofEarthshine

Nominal 1.4° Width of Opening

Prototype Scanned Across Sun @ 1 RPMAveraged Data

CINEMA PDR- MEC15

MECHANICAL – Sun Sensors

Horizontal Sweep Across Sun

-1

0

1

2

3

4

5

6

7

0.500 1.000 1.500 2.000 2.500 3.000

Raw Data

Noise ~ -0.3 VSlope of Rise: ~ 35 V/sec Timing Error = 9 ms < 0.1°

Large Noise PeaksProbably Due to DC Motor

CINEMA PDR- MEC16

MECHANICAL – Mag & Boom

CINEMA PDR- MEC17

MECHANICAL – Mag & Boom

• 1 meter stacer boom

• Held by TiNi P5 Pin Puller

• Magnetometer in 2 x 2 x 2 cm compartment

• Magnetometer Harness

• 18 strands of 36 AWG magnet wire

• Aracon braid for Harness Jacket

• Non-Magnetic Braid on 6 cm closest to sensor

• Fixed to Mag Mount and Base of Boom via

Screw-Down Fixtures• 18-pin Connector at End

CINEMA PDR- MEC18

MECHANICAL – Mag & Boom

Magnetometer

ChassisMounts

MagnetometerMount

CINEMA PDR- MEC19

MECHANICAL – Mag & Boom

Stowed Stacer BoomRelease

Pin

TiNi Pin Puller

CINEMA PDR- MEC20

MECHANICAL – Mag & Boom

Harness Details

Harness Constraining Fixtures

String Cannister

CINEMA PDR- MEC21

MECHANICAL – Mag & Boom

CINEMA PDR- MEC22

MECHANICAL – Mag & Boom

Harness Assembly

CINEMA PDR- MEC23

MECHANICAL – Mag & Boom

Anti-vibration Clearance

0.02 inches(0.5 mm)

CINEMA PDR- MEC24

MECHANICAL – Mag & Boom

Prototype Harness

•36 AWG Magnet Wire with Polythermalize Insulation

•Examined for Wear Under Microscope

•18 Strands Wound with a winding machine, 1 turn/cm

•Tension on cable not controlled•Inserted into Aracon Braid

•Harness Deploy Tested on Mockup Boom

CINEMA PDR- MEC25

MECHANICAL – Mag & Boom

Boom & Harness Mock Up – Stowed Configuration

ID 2.54 cmAnnulus 3.8 mm

CINEMA PDR- MEC26

MECHANICAL – Mag & Boom

Boom & Harness Mock Up – Deployment Test Video (half speed)

CINEMA PDR- MEC27

MECHANICAL -- STEIN

• Collimator: 40° x 60° FOV

• High Voltage Plates: 4 mm separation, ~1 cm from detector

• Attenuator: Swinging Shutter with BeCu Foil

• Actuated by Two SMA “Nanomuscles”

•Flight Heritage from THEMIS and other Missions

•Low Electrical and Magnetic Noise

• Microswitch Overcenter Mechanism

CINEMA PDR- MEC28

MECHANICAL -- STEIN

Collimator

Attenuator

Detectorand

Electronics

CINEMA PDR- MEC29

MECHANICAL -- STEIN

Collimator Electric Field

Plates

60°

CINEMA PDR- MEC30

MECHANICAL -- STEIN

Attenuator Shutter Shutter with BeCu Foil

4 PixelDetector

CINEMA PDR- MEC31

MECHANICAL -- STEIN

Actuators – Shutter Closed

NanomuscleActuator

Capton Yoke

Pivot Lever

Cam/Lever

Countermass

CINEMA PDR- MEC32

MECHANICAL -- STEIN

Actuators – Shutter Open

CINEMA PDR- MEC33

MECHANICAL -- STEIN

Attenuator Overcenter Mechanism HM Microswitch

Cam

Bearing

Spring Plunger

CINEMA PDR- MEC34

MECHANICAL -- STEIN

Attenuator Mechanism Specifications

Nanomuscle Spring-Loaded Lever

Nominal Stroke 4 mm Mech. Advantage 5.92

Max. Force 70 g (0.69 N) Roller Displacement 0.89 mm

Nanomuscle Lever Plunger Displacement 0.79 mm

Pivot Angle 35° Spring

Rad. w/ 4 mm stroke 6.55 mm Spring Constant 0.17 N/mm

Rad. w/ 3.5 mm stroke 5.73 mm Free Length 15.75 mm

Microswitch

Actuation Force ~0.98 N

Spring Constant ~0.5 N/mm

Operating Stroke 0.15 mm

CINEMA PDR- MEC35

MECHANICAL -- STEIN

Attenuator Mechanism AnalysisMaximum Torque from Nanomuscle and Lever

StrokeLever

RadiusTmax (mNm) FOS 4

3.5 5.73 3.95 0.99

4 6.55 4.52 1.13

CINEMA PDR- MEC36

MECHANICAL -- STEIN

Attenuator Overcenter Mechanism – Cam Analysis

Known Torque for One Cam

0.000

0.200

0.400

0.600

0.800

1.000

1.200

0 5 10 15 20 25 30 35 40

Pivot Angle

To

rqu

e (m

Nm

)

Torque (Known)

Spring Torque

Switch Torque

CINEMA PDR- MEC37

MECHANICAL -- STEIN

Attenuator Overcenter Mechanism – Cam Analysis

Cam Torque Profile

-1.500

-1.000

-0.500

0.000

0.500

1.000

1.500

0 5 10 15 20 25 30 35

Pivot Angle

To

rqu

e (

mN

m)

Powered Cam

Unpowered Cam

Sum of Torques

Actuator (3.5 mm)

Actuator (4.0 mm)

CINEMA PDR- MEC38

MECHANICAL -- STEIN

Attenuator Mounting – How to Locate These Components

CINEMA PDR- MEC39

MECHANICAL -- STEIN

1. Attenuator Mounting – Collimator Shell

CINEMA PDR- MEC40

MECHANICAL -- STEIN

2. Attenuator Mounting – Add Mount Plate

CINEMA PDR- MEC41

MECHANICAL -- STEIN

3. Attenuator Mounting – Add Shutter and Actuators

CINEMA PDR- MEC42

MECHANICAL -- STEIN

4. Attenuator Mounting – Add Switch Mounts

CINEMA PDR- MEC43

MECHANICAL -- STEIN

5. Attenuator Mounting – Add Switches

#0-80 Set Screw for Switch Location

Adjustment

CINEMA PDR- MEC44

MECHANICAL – Mass Budget

Subsystem/Part Proposal PDR

Chassis 470 463

Solar Arrays 375 375

MAG Boom System 113 156

Sun Sensors 10 10

Antennas 15 165

Genesat Avionics

1 battery pack 950 950

2 battery packs ? ?

Transmitter 70 70

Torque Coils 50 85

STEIN Detector Head 70 146

STEIN Electronics 90 90

STEIN HVPS 150 150

MAG Electronics 45 45

Instrument Digital 90 90

Instrument LVPS 150 150

Harnessing 60 60

Thermal 50 50

Total 2758 3055

Highlighted figuresHave changed since the proposal.

Most other figures are rough estimates.