The MAGIC Tether Experiment
21 March 2016
The MAGIC Tether
Experiment
A Demonstration of
DINO’s MAGIC Boom
University of Colorado
Friday, April 02, 2004
The MAGIC Tether Experiment
21 March 2016
The MAGIC Tether Experiment
• Special Thanks To the KC-135 Team for All of
Their Hard Work and Great Contributions
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Cook, Evan
Martinez, Mike
McArthur, Grayson
Mohler, Andrew
Parker, Jeff
Seibert, Mike
Stamps, Josh
Worster, Kate
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Background – DINO
• Nadir Pointing
– Gravity Gradient Stabilization
• Deployable Boom
– Primary Satellite
» 25 kg
– Tip Mass
» 5 Kg
– MAGIC Tether
» Mechanically-Actuated GravityInduced Control
» Stanley Tape Measure
» 6m Long
– Lightband
» 2 +/- .5 ft/sec
» Full deployment after 10 sec
Colorado Space Grant Consortium &
DINO
Tip Mass
Tether
DINO
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The MAGIC Tether Experiment
21 March 2016
Why do This Test
• Is this System Even Feasible?
– Dynamics of the Semi-Rigid System are Poorly
Understood
– Experimental Results of Energy Dissipation
• Over damping will result in inadequate deployment
– Poor gravity gradient stabilization
» Science objectives
» ADCS power Draw
• Under damping would shock the system
– Could damage Electronics and Cameras
– Could recoil, causing a collision
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Expected Results
• The MAGIC Tether team expects the following things:
– Four standard springs will accelerate the relative velocity of the
tip mass with respect to the primary satellite to approximately 1.7
ft/s (0.518 m/s).
– The tip-off rate of the deployment to be less than 1°/s in each
axis.
– Given a deployment velocity of 1.7 ft/s, the optimal value of x0 to
be approximately 0.66” to critically damp the system’s motion as
the tether is fully deployed.
– The semi-rigid tape to be deployed in a controlled fashion
without any recoil at the end of its deployment.
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Experiment Objectives
1. To measure the large-scale and small-scale dynamics
in the deployment
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Linear and angular accelerations
2. To empirically measure how the energy in the system
can be dissipated
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Spring force in the slow-down mechanism
Critically damp tip mass’ motion
3. To demonstrate a successful deployment of DINO’s
MAGIC Boom
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Overview of the Experiment
• KC-135
• Heavy Sat
Light Sat
– 14.6 kg (32.2 lbs)
• Light Sat
– 8.1 kg (17.8 lbs)
Tether
• Tether
– Two lengths of Stanley
Tape Measure (1.0 in)
– 4 ft (1.22 m)
Heavy Sat
• Sensors
Safety
Straps
– 6 Accelerometers
– 6 Rate Gyros
• Equipment Containment
System
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DINO
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The MAGIC Tether Experiment
21 March 2016
Structure
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The structure on each of the two satellites
(Heavy and Light Sat ) is composed of two
1/8” 6061Al plates connected by 4”-tall 1/4"
6061Al box walls.
All sharp edges will be covered with pipe
insulation
Damping
System
TAZ
Foam
Padding
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DINO
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The MAGIC Tether Experiment
21 March 2016
Heavy Sat
The Heavy Sat will have an overall mass of approximately 14.6 kg and
dimensions of 18” x 18” x 6”.
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Circular inner plate
Male mating adapter
TAZ
Deployment springs
Data loggers
Dummy loads
Sensors and batteries
Containment box
• Hand holds
• Pipe insulation
Data
Logger
Colorado Space Grant Consortium &
DINO
Data
Logger
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The MAGIC Tether Experiment
21 March 2016
Light Sat
The Heavy Sat will have an overall mass of approximately 14.6 kg and
dimensions of 18” x 18” x 6”.
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Circular inner plate
Female mating adapter
Spring Adapters
Data loggers
Dummy loads
Sensors and batteries
containment box
• Hand holds
• Pipe insulation
• Braking System
Data
Logger
Colorado Space Grant Consortium &
DINO
Data
Logger
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The MAGIC Tether Experiment
21 March 2016
Entire Assembly
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Push off Springs x 4
• Based on Planetary System’s
Lightband springs
• K = 22.5 lb/in (Per Spring)
• Finitial = 60 lb (Total)
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Tether Description
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The semi rigid tether (SRT)
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Two face-to-face Tape Measures
Commercial, off the shelf part
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Tether Mounting
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Deployment / Braking
System mounted in Light Sat
(Tip Mass)
Boom mounted to Heavy Sat
(Main Satellite) with a tether
attachment system (TAZ),
designed to maintain the
rigid natural shape of the
tether, while providing a
secure attachment.
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Deployment System
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Damping System
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42 Teeth per Rotation
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366 Teeth per Full Deployment
3.1 J Total Energy
• .0085 J / Tooth
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Two 2.5 inch spools
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Geared to counter rotate
• Ratchet and Pawl
• Pawl Spring Loaded
• Adjustable Initial Compression
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DINO
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The MAGIC Tether Experiment
21 March 2016
Damping System
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DINO
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The MAGIC Tether Experiment
21 March 2016
Mechanical Dial
• In Flight Spring Adjustment
• .55in - .75in
• Linear Transducer
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DINO
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The MAGIC Tether Experiment
21 March 2016
Release System
• Deployment initiation
– Mechanical System
– Hand held actuating lever
• Bicycle brake
– Release cable
– Switch
• Incorporated into handle
• Initiates data collection
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DINO
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The MAGIC Tether Experiment
21 March 2016
Testing
DAY 1
• Set Spring to maximum
compression, .75in
(Over Damped)
• Position Test Equipment
• Deploy
• Reset
• Decompress spring
.05in
• Repeat until .55in
compression is reached
(Under Damped)
DAY 2
• Set Spring to maximum
compression in range of
interest
• Position Test Equipment
• Deploy
• Reset
• Decompress spring
desired amount
• Repeat until minimum
compression in range of
interest is reached
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Data Collection
• There will be four sources of data in the MAGIC
Tether Experiment:
– Qualitative observations by the flyers and by the
digital video camera
– Quantitative measurements of acceleration by the six
single-axis accelerometers
– Quantitative measurements of angular velocities by
the six single-axis gyroscopes
– Quantitative measurements of braking spring
compression by the linear transducer
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Safety
• Restraint Straps
– Four cinch straps to hold satellite to base plate during Takeoff/landing
– Two Velcro straps for satellite securing during flight
– Velcro connection between Heavy Sat and base plate during flight
• Safety straps
– 10’ straps connected from the base plate to each satellite
– 6’ strap connecting each satellite
– Braided steel rated to 1000 lbs.
• Safety pin
– Prevent accidental deployment
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Padding on all metal edges
Four handholds per satellite
Safety straps attached to all tools
Fuses installed on electrical lines
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DINO
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The MAGIC Tether Experiment
21 March 2016
Results
• Trends will be extrapolated and scaled to DINO’s full
Deployment length and weight.
• What will happen to the satellite if the damping system does
not perform precisely as planned?
• What are the risks to the Satellite?
• Does the Tether “explode” violently?
• Is the deployment controllable?
• Does the damping occur as expected?
• Real world experience
• Will result in a safer, more reliable system for DINO
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DINO
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The MAGIC Tether Experiment
21 March 2016
Appendix
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
FEA for KC-135
Experiment
Grayson McArthur
The MAGIC Tether Experiment
21 March 2016
G-Load Specs
Takeoff/landing
- Forward 9 g’s
- Aft 3 g’s
- Down 6 g’s
- Lateral 2 g’s
- Up 2 g’s
3 g’s in any direction
- Randomly picked 3 configurations to simulate the structure being
dropped
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
FEA Setup
Program used for analysis → CosmosWorks
Takeoff/landing
- Load acts through the center of gravity
- Outer face of the outer panel on the light side restrained as immovable/no
translation to simulate attachment to base plate
- Global size of nodes set at 0.44469 in. with a tolerance of 0.02223 in.
- Yield strength of Al 6061 used as max. load = 145 MPa or 21030.51 psi
- Factor of safety set at 2 based on the yield strength
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
FEA Setup Con.
3 g’s in any direction
- Load acts through the center of gravity
- Global size of nodes set at 0.44469 in. with a tolerance of 0.02223 in.
- Yield strength of Al 6061 used as max. load = 145 MPa or 21030.51 psi
- Factor of safety set at 2 based on the yield strength
► Thin edge faces of outer plates set as immovable/no translation to
simulate the structure being dropped on those two edges
Colorado Space Grant Consortium &
DINO
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21 March 2016
Results
Stress: Von Mises (VON)
- Measured in pounds per square inch
- VON = (0.5[(P1-P2)2+(P1-P3)2+(P2-P3)2])1/2
- P1,P2,P3 are principle stresses
- Measures stress intensity required for a material to start yielding
Strain: Equivalent Strain (ESTRN)
Displacement: Resultant (URES)
- Measured in inches
- Adds displacement vectors in X,Y,Z direction to get a resultant vector
Design Check
- FOS < 2 area shows as red
- FOS > 2 area shows as blue
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
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Stress
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Strain
Colorado Space Grant Consortium &
DINO
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Displacement
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DINO
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Design Check
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DINO
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Conclusions
The structure will be able to withstand all the prescribed
loads as indicated in NASA document AOD 33897
Experiment Design Requirements and Guidelines NASA
931 KC135A
Structure will survive a 3 g impact such as being
dropped by the flight crew during transition from 0 g
to 2 g
Colorado Space Grant Consortium &
DINO
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Issues and Concerns
Mesh resolution was limited due to computer
memory and time limitations
Boundary conditions being appropriate for load
case
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DINO
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The MAGIC Tether Experiment
21 March 2016
Onboard Support
Equipment
Equipment Containment System
(ECS)
The MAGIC Tether Experiment
21 March 2016
Entire Assembly
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Base Plate
• .125-.25in Al 6061 sheet
• Note, Current design requires
heavy hand construction… It will
not fit within the CNC
• 4 Aircraft mounting location
• 7 handhold, accommodating up to 4
handlers
• Experiment restraint harness
• Safety cable attachment
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Tool Box
• Store bought
• Plastic and steel construction
• Round plastic edges
• Lockable
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Stand Off
• Al 6061
• Industrial strength Velcro
• Non permanent
attachment
• Only for stability, not
critical for LD/TO
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Mechanisms
Michael Martinez
The MAGIC Tether Experiment
21 March 2016
Mechanisms
• Contents:
– Tether Description
– Deployment System
– Braking System
Colorado Space Grant Consortium &
DINO
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21 March 2016
Tether Description
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•
The semi rigid tether (SRT) is constructed of 2
COTS spring metal "tape measures", four feet length
by 1 in wide, curved along their width.
To be configured ‘face to face’, provides greater
stability.
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Deployment System
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
Deployment System
21 March 2016
(cont)
• The MAGIC Tether deployment system
consists of two 2.5 inch spools, geared
to counter rotate and unwind the spring
metal boom in a controlled manner.
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
Deployment System
•
21 March 2016
(cont)
Deployment / Braking
System
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The stowed SRT will be
wound on the two spools
such that when deployed
the two tape measures
will be face to face,
forming a rigid structure.
Tape to spool connection
recessed to reduce
stress at connection
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Braking System
• Velocity control is provided
by a 48 tooth, 2.0 inch
ratchet and pawl system,
with the ratchet shafted to
the geared spool, and the
pawl spring loaded to
provide a loading / braking
force against the ratchet.
• Initial k for spring
~ 0.245 N/mm
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Release System
• Deployment initiation
– Mechanical System
– Hand held actuating lever
• Bicycle brake
– Release cable
– Switch
• Incorporated into handle
• Initiates data collection
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Tether Reset Device
• Tether reset device
• Two options
– Manual crank
– Electric drill
• Flexible extension used to reach
the drive shaft easily
• Attached to the toolbox by a steel
cable tether
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Tether Mounting
•
•
Deployment / Braking
System mounted in Light Sat
(Tip Mass)
Boom mounted to Heavy Sat
(Main Satellite) with a tether
attachment system (TAZ),
designed to maintain the
rigid natural shape of the
tether, while providing a
secure attachment.
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Sensors
Kate Worster
Michael Seibert
The MAGIC Tether Experiment
21 March 2016
Sensors: Objectives
• The Sensors Subsystem is designed to measure the
large-scale and small-scale dynamics of the experiment
during its deployment, including linear and angular
accelerations imparted by the tether
• Sensors and Data Acquisition
– Onboard storage of science and engineering data
– Provide data for post-flight analysis
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
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Sensors & Data Acquisition System Functional Diagram
Heavy Side
HVY_AZ
15V
HVY_AY
HVY_AZ
HVY_G1
HVY_G2
HVY_G3
9V
KS
Data Logger
Kill Switch
Data Signal
KS
Power lines
Colorado Space Grant Consortium &
DINO
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The MAGIC Tether Experiment
21 March 2016
Sensors & Data Acquisition System Functional Diagram
Light Side
LHT_AZ
LHT_AY
LHT_AZ
LHT_T_D
LHT_G1
LHT_G2
LHT_G3
15V
9V
KS
Data Logger
Data Signal
Power lines
Colorado Space Grant Consortium &
DINO
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Functional Requirements
Requirements
Accelerometer
Rate
Gyro
Linear
Transducer
Data
Logger
Laptop
Measure
acceleration
Measure twist
& rotation
Measure
spring
compression
Data
acquisition &
analysis
Colorado Space Grant Consortium &
DINO
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Gyro Specifications-ADXRS150EB
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Surface-mount package of 7mm x 7mm x 3mm and mass of 0.5 grams.
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Each rate gyro has a resolution of 0.05/s/Hz and a dynamic range of
150/s.
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Input voltage of 5.00v DC from onboard power supply and a quiescent
supply current between 6.0-8.0 mA.
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DINO
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Accel. Specifications-ADXL150
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Nominal sensitivity: 38.0mV/g and a maximum sensitivity of 43.0mV/g.
The functional voltage range 4.0V - 6.0V and a quiescent supply current of
1.8mA for nominal operation and 3.0mA as the maximum supply current.
Resolution: 1.0mg/Hz
Dynamic range: 80dB
Each can withstand 2000 g’s when un-powered and 500 g’s when powered
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DINO
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9V Power Supply Specifications
9V ZnMn2 battery
• Average voltage of 9.0 volts
• Average capacity of 655mAhr (0.8 volts per cell
• Weighs 45.6 grams (1.6oz) and has a total
volume of 21.2cm3 (1.3in3).
Colorado Space Grant Consortium &
DINO
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15V Power Supply Specifications
1.5V Alkaline Zinc-Manganese Dioxide (ZnMn2)
battery
• Average voltage of 1.5 volts
• Average capacity of 3135mAhr (0.8 volts per
cell
• Weighs 23.0 grams (0.8 oz) and has a total
volume of 8.1cm3 (0.5in3).
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DINO
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COTS Parts Status
Part
Availability
Status
ADXL150
In stock on Analog
Devices website
Not yet ordered
ADXRS150
In stock on Analog
Devices website
Not yet ordered
Inhibits
Available at CSGC and
JB Saunders
Have some, others will
be purchasing next week
Sensor housing, 18
gauge wire, prototype
board
Available at JB Saunders Purchasing next week
Colorado Space Grant Consortium &
DINO
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Data Collection
• Omnidata Polycorder and
Data Fielder loggers
• 415K on board storage
• 25Hz sampling rate
• Start/Stop trigger capability
• 10 analog input channels
• 0V-5V, 0V-10V & 0V-15V input
ranges
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Data Collection
• Heavy Sat
– 6 Inputs
• 3 Accelerometers
• 3 Rate Gyroscopes
• Light Sat
– 7 Inputs
• 3 Accelerometers
• 3 Rate Gyros
• 1 Linear Transducer
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Data Collection
• Configuration
• Data Retrieval
– Omnidata DF200 GUI
– RS-232
– Variables
• Sampling Rate
• Saving Rate
• Channel Input Voltage
Range
– Omnidata DF200 GUI
– RS-232
– Data Retrieval Options
• Histogram
• Spreadsheet
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DINO
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Ground Support Equipment Requirements
• Laptop
– RS232 Capability
• Serial Port
• USB to Serial adapter
• Spring Set Screw Calibration
– Calipers
• Initial state displacement measurement
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Procedures
Jeff Parker
The MAGIC Tether Experiment
21 March 2016
In-Flight Procedures
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1.
2.
3.
4.
5.
6.
7.
Preparations for the First Parabola
These procedures must be followed to set the experiment up for the first
parabola:
Flyer B: verify that the digital video camera is on and working normally.
Flyer A: verify that the sensors’ wiring harness is connected to the first data logger on
each satellite.
Flyer A: turn on power to both satellites by switching the kill switch into the on
position. Flyer B: verify that power has been turned on. An LED will indicate normal
power for each battery system onboard. Flyer B: replace any battery packs that
require replacing.
Flyer A: configure each of the two data loggers using a brief set of instructions
attached clearly to the equipment containment toolbox. Flyer B: verify every
instruction as they are entered.
Flyer B: verify the setting of the slow-down mechanism.
Flyer B: remove the four cinch straps from the experiment and stow them in the
equipment containment toolbox. Flyer A: assist as necessary. This leaves two Velcro
straps still attached to the experiment system.
Flyers A and B: visually inspect the experiment to make sure that everything is in
working order, including the Velcro straps, the safety straps, the deployment system,
the safety deployment pin, and the slow-down mechanism.
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In-Flight Procedures
• Free-Fall minus three minutes
8. Flyer A: remove the safety deployment pin and Velcro it to the side of Heavy Sat (it
also has a short tether attached to it to restrain it from possibly floating away).
9. Flyer B: check the temperature of the cabin using the thermometer attached to the
toolbox.
10. Flyer B: record all settings and activities in the logbook. The ambient temperature, air
currents, and other environmental factors should be noted.
• Free-Fall minus one minute
11. Flyer A: release one of the two remaining Velcro hold-down straps. If the experiment
behaves in an unexpected manner, immediately replace the straps and inspect the
deployment system. This may sacrifice the parabola, but it could avoid releasing an
uncontrolled deployment.
12. Flyer B: prepare the active data logger on each satellite. This requires about eight
key-strokes that will be easily visible near the data logger on the system.
13. Flyer A: release the last hold-down Velcro strap (the satellite system still has Velcro
attached to its base to keep it still on the base plate).
14. Flyers A and B: situate yourselves such that your feet are restrained by the footrestraints and you are on opposite sides of the flight system. Make sure that Flyer A
will be near Heavy Sat and Flyer B will be near Light Sat upon deployment
completion.
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In-Flight Procedures
•
Free-Fall
15. Flyers A and B: make sure you are stable in the foot-restraints and prepared for the experiment.
16. Flyers A and B: lift the experiment off of the base plate and maneuver into the correct position over
the base plate. During the deployment, the Light Sat will move approximately 2.5 feet and the
Heavy Sat will move approximately 1.5 feet. Hence it is important to deploy the system in the
proper location in space such that the full deployment occurs within the specified experiment
volume. This position is marked on the base plate.
17. Flyer A: hold and stabilize the satellite system from the side such that the deployment action will
occur sideways and that Flyer A will be near Heavy Sat and Flyer B will be near Light Sat upon
deployment completion.
18. Flyer A: take hold of the deployment trigger.
19. Once all personnel are clear from any interference with the MAGIC Tether’s deployment (keeping
in mind that both the primary and tip mass systems will move upon deployment), then Flyer A:
carefully release the system and trigger the deployment. Keep hold of the deployment trigger,
both as a safety and because letting it go might induce added dynamics into the system.
20. The separation springs activate and the deployment proceeds.
21. The tether is reeled out from the Light Sat; accelerometers and rate gyros on both bodies
measure the linear and rotational accelerations experienced by both systems; the data are
recorded on the data loggers.
22. The slow-down mechanism removes energy from the moving system from the moment of
deployment until the system comes to a stop.
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In-Flight Procedures
23.
24.
25.
26.
27.
•
28.
29.
30.
The Light Sat either comes to a halt with respect to the Heavy Sat or it recoils after
the tether stretches taut. Flyer B records the resulting dynamics in the logbook.
Flyer B then records the distance that the tether deployed by observing the tic
marks on the tether.
The maximum separation velocity between the two bodies is 1.7 ft/s, slow enough
to grapple if need be. Therefore, if any recoil action exists that appears to threaten
a collision between the two satellites, then Flyer A: carefully grapple the two
satellites prior to impact. If, however unlikely, the system recoils at an
unexpectedly high velocity, then Flyer A: remain in a safe position and wait until the
system settles down before retrieving the hardware.
If not otherwise retrieved, Flyer A: take hold of the Heavy Sat.
Flyer B: take hold of the Light Sat.
Flyer A: place the Heavy Sat onto the Velcro swath on the base plate to secure it
before the end of the free-fall.
End of Free-Fall
Flyer B: keep hold of the Light Sat while the aircraft’s accelerations increase.
Flyer A: use the tether-reset device to recoil the tether onto the spools.
Flyer B: mate the Light Sat onto the Heavy Sat, compressing the separation
springs. The deployment device will not allow the springs to release until triggered,
so there is no danger of accidental deployment during this phase.
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In-Flight Procedures
31.
32.
33.
34.
35.
36.
•
37.
38.
39.
40.
41.
42.
Flyer A: strap the system down using the two Velcro hold-down straps.
Flyer B: command the two active data loggers to stop recording data.
Flyer B: adjust the knob on the slow-down mechanism to set the slow-down spring to the next
desired value of x0. Flyer A: verify the set value.
Flyer B: record all dynamics, activities, and new settings in the logbook. The ambient
temperature, air currents, and other environmental factors should be noted.
Flyers A and B: while waiting for the next free-fall, visually inspect the system for signs of
fatigue, failures, or damage. If power sensors indicate a battery pack low on power, replace the
battery pack at this time. If a data logger is nearing memory capacity, then switch the power
and data cables from the active data logger to the spare data logger. Follow the startup
procedure listed in line 4.
Return to step 11 and repeat.
End of Flight
Flyer A: place the deployment safety pin into the deployment system.
Flyer A: secure all four additional cinch straps on the system.
Flyer B: shut the data loggers down following the simple procedures listed on the side of the
structure.
Flyer B: flip the kill switch on each satellite, turning off power to each system.
Flyer A and B: verify that all straps are in place and secure.
Flyer A and B: verify that all components are stowed and secure.
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The MAGIC Tether Experiment
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Emergency Procedures
•
In the event of an emergency, the following procedures
will be followed. These procedures will be posted
directly on the experiment, detailing exactly how to shut
the system down quickly.
1. If either satellite is not strapped to the base plate, follow the
appropriate procedures here:
•
•
•
•
•
Flyer A: take hold of the Heavy Sat
Flyer B: take hold of the Light Sat
Flyer A: place the Heavy Sat on the base plate
Flyer B: mate the Light Sat on the Heavy Sat
Flyer A: strap the system down using the two Velcro straps
2. Switch the master kill switch on each satellite to shut off all
power on each satellite.
3. Shut off the power to the data loggers.
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The MAGIC Tether Experiment
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Safety
• Restraint Straps
– Four cinch straps to hold satellite to base plate during Takeoff/landing
– Two Velcro straps for satellite securing during flight
– Velcro connection between Heavy Sat and base plate during flight
• Safety straps
– 20’ straps connected from the base plate to each satellite
– 6’ strap connecting each satellite
– Braided steel rated to 1000 lbs.
• Safety pin
– Prevent accidental deployment
•
•
•
•
Padding on all metal edges
Four handholds per satellite
Safety straps attached to all tools
Fuses installed on electrical lines
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Data Analysis
Jeff Parker
The MAGIC Tether Experiment
21 March 2016
Data Types
• There will be four sources of data in the MAGIC
Tether Experiment:
– Qualitative observations by the flyers and by the
digital video camera
– Quantitative measurements of acceleration by the six
single-axis accelerometers
– Quantitative measurements of angular velocities by
the six single-axis gyroscopes
– Quantitative measurements of braking spring
compression by the linear transducer
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Data Reduction
• Accelerometers and rate gyros have biases and
scale factors
– Calibrated by temperature measurements and
specific calibration measurements
• Analog measurements between 0 – 5 Volts
• Expected Dynamics:
– Large acceleration spike at beginning of deployment
– Diminishing decelerations until end of tether or all
energy is dissipated
– Possible dynamics due to tether’s deployment
– Possible recoil dynamics due to excessive energy
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The MAGIC Tether Experiment
21 March 2016
Expected Results
• The MAGIC Tether team expects the following things:
– Four standard springs will accelerate the relative velocity of the
tip mass with respect to the primary satellite to approximately 1.7
ft/s (0.518 m/s).
– The tip-off rate of the deployment to be less than 1°/s in each
axis.
– Given a deployment velocity of 1.7 ft/s, the optimal value of x0 to
be approximately 0.66” to critically damp the system’s motion as
the tether is fully deployed.
– The semi-rigid tape to be deployed in a controlled fashion
without any recoil at the end of its deployment.
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