full mission simulation report temple university fred avery, gene council, ny’jaa bobo, salvatore...
TRANSCRIPT
Full Mission Simulation Report
Temple UniversityFred Avery, Gene Council, Ny’Jaa
Bobo, Salvatore Giorgi, Jay Shukla4/21/12
Mission Overview• Measure the earth’s
magnetic field as a function of altitude
• Measure flight dynamics of the rocket
• Capture biological samples in the atmosphere
• Identify types and concentration of samples as function of altitude
• Measure UV intensity as function of altitude
• Identify UV damaged DNA in samples
Figure: A UV radiation induced thymine-thymine cyclobutane dimer (right) is the type of DNA damage which is undone by photolyase.
Mission OverviewCurrent Problems• Fully integrated payload is still not complete– Not able to get plates cut– Standoffs ordered but not delivered
• Magnetometer is still not functioning with microprocessor– Looked into other models, but all cheap sensors require I2C
protocol, which seems to be where the problem is
• Decoding the spectrometer data– Spectrometer uses data compression when transmitting data– Currently working on method to decode the compression– In the end, this is not needed as we have enough memory to
store uncompressed data3
Mission Overview - Testing
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Tests Previously Completed• Filtration System Temperature Tests• Filtration System Pressure Tests• Data Collection• Power• Spin• Plate Stress/Strain Simulations
Mission Overview - Testing
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New Tests Completed• Additional Power Tests• Additional Data Collection Tests• Standoff Simulations– Deflection– Stress– Loading
• Spectrometer Integration Time• New Center of Gravity Simulations• System Activation
Subsystem Overview - Mechanical
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• No changes have been made to this subsystem since last report
• Filter system consists of four filter holders, one manifold and four servo motors
• Servos are mounted to top of manifold and control the air flow to the filter holders.
Subsystem Overview - Electrical
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• No official changes have been made to this subsystem since last report
• Electrical system consists of one microprocessor, two accelerometers, magnetometer, gyroscope, and a spectrometer
• The magnetometer will be mounted on the top plate while the remaining item will be located on the bottom plate
Subsystem Overview - Power
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• No changes have been made to this subsystem since last report
• A total of 3 batteries will be used to power the system
• All sensors will be powered by microprocessors
• System activation will be done with a RBF pin
Mechanical - Structure
Standoffs– Size: 5/16” Hex Size, 8-32 Screw Size, 2”
length– Same type and size as Drexel’s though ours
are made of steel
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Plate Problems
–Laser Cutter will now be used to machine plates–Makrolon (Polycarbonate) cannot be laser cut–Acrylic will now be used in co ordinance with Drexel’s payload
Mechanical - Structure
Center of Gravity• X = 1.00 in• Y = 0.91 in• Z = 0.94 in
Current Weight• 6.04 lbs• Approximately 3 lbs per plate• Steel blocks (~1 in3) will be used to add
weight (~1 lb each)
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Mechanical – Parts List
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Part Number Needed for Flight
Number In Possesion
Plates 2 4
Standoffs 5 10
Filter Holders 4 8
Tubing (Filter System) ~1’ 25’
Tubing (Drop Down) 8’ 20’
Servo Motors 4 8
Manifolds 1 4
Leur Lock to 1/4” barbed 1 25
Leur Lock to 1/8” barbed 8 25
Mechanical – Parts List
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Part Number Needed for Flight Number In Possesion
Barbed Y fittings 3 10
NPT Femal to 1/8” bardbed 4 25
Filter Holders 4 8
Voltage Regulator 1 5
Servo Microprocessor 1 2
Electronics Microprocessor 1 2
Accelerometer 1 2
Magnetometer 1 2
Spectrometer / Fiber Optics Cable / Cosine Corrector
1 1
SD Card Reader / SD Card 1 2
Mechanical - Standoffs
• Deflection Simulation– As a worst case scenario, wind
gusts may affect structure and standoffs could be affected
– The maximum force expectancy during flight is about 3380 N
– Standoffs will deform about 0.5 mm (~0.02 in) if at all
– Color represents severity and value of deformation (Red being maximum, blue being minimum)
– The most deformation will occur in the center of standoff due to the fixed ends
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Mechanical - Standoffs
• Shearing Simulation– A force of 3380 N in each axis
may affect the payload structure
– This force will not highly affect the standoffs being used
– Only a moderate amount of stress will result from the force expected and will not exceed material strength
– The fixed ends cause standoffs to deflect
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Mechanical - Standoffs
• Total mass of canister is 9.07 kg• Max loading expected during
flight is 38 g• Total force acting on standoff is
9.07 kg*38*9.81m/s2 = 3380 N• Stress expectancy during flight
is 74,700 Pa • Standoff strength is 5.14×108 Pa• Expected Stress will not exceed
Standoff Strength• Material is able to withstand the
force expectancy
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Mechanical – Filter System• Fully constructed• Processor is programmed with all
timing information• Batteries proven to power system• Fully functional during previous
temperature tests• Plan to further minimize leak with
high vacuum grease• Grease will not contaminate filters• Need to wait until end of semester to
get access to vacuum pump (first week of May)
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Electrical – System Activation
• Previously changed from g-switch to timer activation
• We use a delay command• Designed software so that we change constant
parameter minute to change the activation time• This will give us more flexibility in the event our
activation time changes before launch• delay command in arduino delays the program by
a specified time in milliseconds• Example:
– delay(minute*60*1000)• Parameter is unsigned integer, which must be less
than 232
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Electrical - Spectrometer
• Higher integration time may saturate data• Low integration time will not give relevant data • Canister spins at 5.6 rev/sec and thus field of view passes
over the sun at least 5 times per sec• Graph above shows spectrum with various integration times
on sunny day with fiber optics cable pointed directly at sun18
Electrical - Spectrometer
• Above graph shows spectrum with varying on a very overcast day with fiber optics cable pointed away from sun
• Will do further testing in Chemistry department to determine integration time needed– Tests will using laser pulses to simulate optical port facing
sun while spinning19
Power (EPS)
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Battery Initial Voltage (V) Final Voltage (V)
Electronics Microprocessor
9.07 8.65
Servo Microprocessor 9.01 8.90
Servos 9.02 7.22
• Above table shows voltage values for 30 minute flight simulation
• Batteries were able to power everything, as expected
Software
• Data collected for 30 minute flight is 1.4 MB with spectrometer included
• Problems– Software still not working for
magnetometer and pic32 board– Software not able to run through
multiple spectrometer integration times while sampling other sensors
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Action Item Summary
Week 1• Cut plates (or at minimum, schedule time with
Drexel for cutting)• Purchase drop down tubing and fittings• Detailed full canister integration procedure
Week 2• Full canister center of gravity simulations• Finalize spectrometer integration time• Test vacuum grease• Finalize all sensor problems
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Action Item Summary
Week 3• Have entire canister constructed
– Fully integrated with Drexel– Drop down tubing integration completed sorted
Week 4• Complete all Launch Readiness tests
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Conclusions
• Besides being physically connected we feel as though our system is very close to being launch ready
• Focus will be on working with other teams to get the full canister ready for launch
• With end of semester next week, all team members will be able to give this project their full attention 24