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