embry-riddle aeronautical university molly stagnitti...
TRANSCRIPT
Embry-Riddle Aeronautical University Molly Stagnitti, Anthony Pritchard, Kriszelda Menez
November 30, 2012 1
Molly Stagnitti
2
RockSat-C 2013
CoDR
“Project PHIDO’s mission is to design, build, and launch an optical instrument to determine how the intensity of UV radiation changes with altitude in order to deduce an ozone density profile of the atmosphere. This profile will serve as an initial validation of the instrument functionality in a space environment.” Mission Requirements: Form a payload design utilizing an optical port from its desired function
while adhering to rocket constraints Construct the support systems, then calibrate and test the instrument Validate the device and the supporting system by rocket flight and data
collection
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RockSat-C 2013
CoDR
Expect to correlate UV intensity to ozone density as a
function of altitude in order to compare the profile to previous data and current models
The design will benefit future senior design teams at Embry-
Riddle Aeronautical University by serving as a viable prototype for a student CubeSat-mounted photometer
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RockSat-C 2013
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Team Leader Team Phido Molly Stagnitti
Science Team Greg Shinaberry
Dan McIlveen Alena Thompson
Faculty Advisor Dr. Matthew Zettergren
Sponsor Florida Space Grant Consortium
Member Team Phido Anthony Pritchard
Member Team Phido Kriszelda Menez
Data/Software Greg Shinaberry
Dan McIlveen Alena Thompson
STR Molly Stagnitti
Kriszelda Menez
OPTICS Anthony Pritchard
PMT/PS Molly Stagnitti
Anthony Pritchard Kriszelda Menez
Main Faculty Advisor Dr. Peter Erdman
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CoDR 6
Altitude: 60km
Ozone
Density≈0
t≈933 s
Splash Down
Altitude: 95 km
Instrument Power Up
Begin Useful Data
Collection
t=0 s
Altitude: 95 km Apogee
End of Useful Data
Altitude≈110-
120km
Altitude: 52 km
Altitude: 75 km
Chute Deploys
t≈489.2 s
Altitude: 75 km
Terrier Burn: t≈5.2 s
Coast: t≈9.8 s
Orion Burn:
t≈25.4 s
End Data Collection
Shortly after
Apogee
RockSat-C 2013
CoDR 7
Calibration of the PMT with control source of light (of known photon count) allows us to correspond its current output to intensity, or number of photons
Expected counts (calibration will determine exact numbers):
▪ The PMT is a pulse-counting type detector, it emits one count per photon (expect a few MHz for intense UV source photons)
▪ Data resolution depends upon speed of microcontroller counter and design of the data collection system (team OASIS will make it 15-18 kHz for ten counts per degree resolution)
RockSat-C 2013
CoDR 8
Once photon count is found from the PMT’s current output, team OASIS will use numerical integration to calculate the density of ozone as a function of altitude
Numerical integration will yield an optical depth expression which density can be resolved from (this is unique to the UV-b band):
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RockSat-C 2013
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Altitude (km)
0—15 <0.5—1
15—25 1—5
25—35 4—1
35—55 1—≈0
RockSat-C 2013
CoDR 11
We have not eliminated any mission objectives
High Risk: 1. If connections are disrupted by vibration testing or launch conditions then data cannot
be collected
2. If the power system is unable to properly control the power to the detector system it will destroy our PMT
3. If the PMT breaks during vibration testing or launch conditions then data cannot be collected
Prevention Plan: 1. We will be performing vibration tests for the instrument and each of the subsystems
2. We will be performing electrical tests to ensure our power system is safe and operates as expected
3. We will protect the PMY with RTV11
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Molly Stagnitti & Kriszelda Menez
RockSat-C 2013
CoDR 13
Interface Name Brief Description Potential Solution
STR/PLT1 This top plate that has the electrical power system mounted to it will then be mounted onto the canister top plate.
The plate will be secured using bolts.
EPS-DS/PLT1 The electrical power system and data system which includes our DC-DC converters, batteries and data system will all be placed in a housing unit that is mounted to our top plate.
The housing unit is made of aluminum. Exact dimension of the housing unit will be determined by the CDR. Four bolts at the corners of the housing secure it to the plate.
MR/PMT
The mirror will enclosed within its own housing unit to make sure that all the light is focused into the PMT housing unit. The mirror housing unit will be attached to the PMT housing unit.
The mirror housing unit will be mounted to the PMT housing unit using four small bolts.
PMT/PLT2
The detector consists of an aluminum housing unit and its bottom will be mount to a second plate deck rigidly. The PMT/high voltage supply will be secured within the housing.
Bolts will secure the housing. RTV-11 will secure the PMT/high voltage within the detector.
PLT3/STR There will be a third plate attached to the second plate using metal rods. This third plate is used to mount the whole system to the bottom plate of the RockSat-C canister.
The plate will be secured using bolts. This plate will help ensure that the second plate holding the PMT housing and mirror housing unit are at the correct height of the optical port.
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Plates Data/Power
System
Mirror/Mirror
Housing
Detector
Housing Support
Rods
Optical Port
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CoDR 15
236.22mm
241.3mm
22.25mm
31.75mm
81.00mm There are three
plates in the
design. Each
plate has a
thickness of
6.35mm.
RockSat-C 2013
CoDR 16
The payload design consists of
several major components:
Plates
Rods
Data/Power System Housing
Detector Housing
Each of these components will be
shown in detail in the following
slides.
RockSat-C 2013
CoDR 17
1. Circuit Board:
50.8x38.1x3.175
2. Batteries
H: 46.41mm
L: 26.62mm
W: 17.50mm
3. DC-DC Converters
H: 50.01mm
L: 10.01mm
W: 24.99mm
1
2
2
2
3
3
22.225mm
152.4mm 152.4mm
RockSat-C 2013
CoDR 18
• The PMT will be secured using
RTV11, which is a white, two
component, low viscosity potting
compound that cures at room
temperature to a soft pliable
rubber.
• It’s excellent electrical
properties make it a candidate
material for both high and low
voltage electrical assemblies. It
helps cushion against
mechanical shock and vibration.
http://www.mgchemicals.com/products/rtv-
silicones/potting-compounds/rtv11/
Light
PMT Pre-amp/
Discriminator
HV Supply
RockSat-C 2013
CoDR 19
Changes: • Rod placement: Staggered the rods that connect the plates so that the structure
has a smaller risk of breaking during vibration; more stability
• PMT housing: The new housing design has been previously tested with its components, and it simplifies the design of the optical system. The hole in which the light is directed is larger than that on the previous housing and we will be able to place the PMT closer to the mirror in order to optimize focus
• DC-DC converters were changed because the total amount of voltage is now
higher for the microcontroller
• May need more batteries due to the higher amount of voltage needed for the microcontroller
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CoDR 20
We have referenced previous data and experiments to assist us in final decisions regarding materials and component choices.
Calculations have been done in order to assure the payload will survive flight.
We are planning on performing electronic and optical tests for the separate subsystems, as well a low pressure vacuum test for the entire instrument.
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Kriszelda Menez
RockSat-C 2013
CoDR 22
PMT
Detector
Pre-Amp/
Discriminator
Photomultiplier Tube
Counter Data
System
Data Storage/
Control System
Data System
Batteries HV Supply DC/DC
Converter
Electrical Power System
Wallops Flight
Facility Payload
Interface
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CoDR 23
EPS/Data subsystem will have one breadboard to organize wiring, complete internal circuits, and mediate between the detector system and power system
Changes/Finalizations since PDR:
HV supply is for the 28mm PMT (larger than HV supply of 13mm PMT)
▪ Need 15 V DC-DC converter to supply input power instead of 12 V converter that would be needed for the 13mm PMT HV supply
Microcontroller needs up to 12 V input (previously assumed 5 V) ▪ Need 12 V DC-DC converter to supply input power instead of 5 V converter
that would be needed for other microcontroller
RockSat-C 2013
CoDR 24
Payload will be activated by electrical system when the command line closes the switch at T-2
Batteries
Detection System
Power Control/Data
Storage System
Wallops
Control
Data
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Anthony Pritchard
RockSat-C 2013
CoDR 26
Input Power
Detector Outputs
SD Card Data Storage
Closes all programs and
turns off instrument
Microcontroller starts code
Detector Commands
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CoDR 27
Initialize Microcontroller SLEEP MODE
Initialize clock and start timer.
Initialize communication between Arduino and SD Card
Initialize communication between Arduino and PMT
Record data from PMT to SD card
End communication with PMT
End communication with SD CARD.
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CoDR 28
RockSat-C 2013
CoDR 29
RockSat-C 2013
CoDR
7-12 Low Voltage Source from PHIDO
SD CARD HOLDER
SCK
MISO MOSI
SS
PMT DIGITAL INPUT GROUND
3.3 Regulated Voltage
RockSat-C 2013
CoDR
Pin SD INPUT
1 NC Not connected
2 CS SS
3 DI MOSI
4 VDD VDD
5 CLK SCK
6 VSS Ground
7 DO MISO
8 RSV Reserved
RockSat-C 2013
CoDR
SD CARD
Voltage Input (7-12V)
Ground
All other wiring is soldered from Shield to Arduino
Breadboard for additional circuitry
PMT INPUT
Additional Potential Inputs
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Anthony Pritchard
RockSat-C 2013
CoDR 34
A Finite Element Analysis was done
on main structure
Deformation in one of the top rods
Slight bending caused by the 25G
load
Was unable to determine exact von
Mis stresses
RockSat-C 2013
CoDR 35
Arduino microcontroller was prototyped (3 were purchased)
The rate at which the Arduino can write to the SD card
was tested in order to view our maximum sampling rate
The microcontroller meets our requirement of nearly 10 samples per degree of turn (18 kHz max) using data packets
RockSat-C 2013
CoDR 36
Write 187.62 KB/sec
Maximum Latency: 22708 μsec
Minimum Latency: 84 μsec
Average Latency: 527 μsec
Read 314.64 KB/sec
Maximum Latency: 2972 μsec
Minimum Latency: 80 μsec
Average Latency: 312 μsec
EXCEEDS MINIMUM WRITING/READING SPEED for DESIRED
INPUT SIGNAL
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CoDR 37
Mass Budget
Subsystem Total Mass (lbf)
Plates 4.611
Rods 0.613
Screws 0.0814
Power/Data System Housing 0.896
Power/Data System Housing Lid 0.132
Microcontroller 0.0919
DC/DC Converters 0.159
Batteries 0.278
Circuit Board/Wiring 0.07
Mirror 0.310
Detector Housing 1.60
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CoDR 38
Subsystem Total Mass (lbf)
PMT 0.099
High Voltage Supply 0.0992
Pre-amp Circuit Board 0.030
PMT Housing Lids 0.06
RTV11 0.174
Rocksat-C Canister 6.9
Ballasts 3.80
Total 20
Over/Under (0.0045)
RockSat-C 2013
CoDR 39
Power Budget (Input Requirements)
Subsystem Voltage (V) Current (A) Time On (min) Amp-Hours
Microcontroller 12 0.090 (o/p of 0.5 max) 5 0.0075
Preamp/Disc. 5 0.05 5 0.00417
12V DC-DC 24 (o/p of 12.1V) 0.0643 (o/p of 1.3) 5 0.00536
Batteries 27 (o/p of 0.0165) 5 (o/p of 0.00476)
PMT 1250 0.000125 5 1.04*10-5
HV Supply 15 ~0.025 5 0.00208
15V DC-DC 24 (o/p of 15.1) 0.0186 (o/p of 1.0) 5 0.00155
Batteries 27 (o/p of 0.0165) 5 (o/p of 0.00138)
(Batteries) Total (A*hr): (o/p of 0.00614)
With a total Amp-hour requirement of 6.14mA*hr, the 9 Volt NiMH batteries which are rated at 175 mA*hr are marginally sufficient. The short operation time and our low power requirement to the PMT system allows the instrument to easily have enough power throughout the duration of operation.
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Kriszelda Menez
RockSat-C 2013
CoDR 41
• The power system housing, plates, and rods will all need to be manufactured
• The batteries, DC-DC converters, PMT, diffuser, and filters need to be procured
Date Event
11/29/2012 Order Parts
11/29/2012 Send in drawings for parts to Machine Shop
Receive Parts
1/8/2013 Start to implement parts together
1/10/2013 Finish implementing parts
RockSat-C 2013
CoDR 42
• Pre-amp/discriminator will be soldered next semester by Team Phido
• The high-voltage supply will be procured when we order the parts before winter break
• We anticipate about 3 revisions of the electronics
• Testing plan is in project management section
Date Event
12/4/2012 Order high-voltage supply
1/8/2013 Start soldering pre-amp/discriminator
1/15/2013 Begin testing of electronics
1/16/2013-2/14/2013 Revise electronics
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CoDR 43
Complete? Event
Find data rate needed to produce profile for numerical analysis
Compare/Contrast microcontroller apparatuses that can potentially write to SD cards at the needed data rate
Purchase the top two potential microcontrollers to test
Construct both test microcontroller apparatuses to write and read data to SD card
Dec 3 Test the speed, efficiency and durability of each microcontroller and select best microcontroller with inputs similar to PMT
Jan 15 Using best microcontroller, write C++ code according to the code structure outline
Jan 25 Test Microcontroller code with simulated PMT input
Feb 7 Implement with PHIDO instruments and test output
Feb 20 Fine tune and finish instruments
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Anthony Pritchard & Kriszelda Menez
RockSat-C 2013
CoDR 45
Separate Subsystem Testing Electronic tests Optical tests
Instrument Testing
Vibrational tests Low pressure vacuum tests Structural analysis test
Testing will begin on January 15, immediately after implementing the parts into the payload
RockSat-C 2013
CoDR 46
It is important to verify that the electronic devices perform as expected. Variations can easily damage the sensitive photomultiplier tube
Faux circuits imitating the power input to each electrical component (two DC-
DC converters, microcontroller, high voltage supply, photomultiplier tube, preamplifier/discriminator) will be analyzed in order to confirm their performance capabilities before integration
Microcontroller must be able to read from the PMT and write to the SD card fast enough to achieve a resolution of 10 samples per degree of turn of the rocket Tests have been conducted and are presently being conducted in order to
confirm the maximum rates. The microcontroller is connected to a computer and the SD card to observe performance
RockSat-C 2013
CoDR 47
PMT must be extensively tested before integration to discover its characteristic response to a known light input source
Intense ultraviolet light from a deuterium lamp light source will be focused
upon the photocathode with a mock optical system in order to attain expected output counts from a known solar spectrum and known intensity in order to simplify and validate post-flight data analysis
EPS Testing Scheduling: Each component will be tested when they arrive (within 3-10 weeks from
now) to ensure that they work as expected. The microcontroller is currently undergoing testing and will continue to be tested throughout construction of the photometer. The PMT is expected to be tested in full sometime in February.
RockSat-C 2013
CoDR 48
Software testing progress is interdependent upon EPS and detection system construction and integration (except for data analysis code, which has already been successfully composed and tested for the expected results model) The code for the data storage system has already been tested successfully.
The code must be modified to incorporate incoming PMT signals
Current goal of the science team is to complete code for power control to the detector system before the detector system is tested
RockSat-C 2013
CoDR 49
After subsystem level construction and testing has been completed and the payload is fully integrated, certain system tests will be performed
Low pressure test: To ensure our EPS is fully insulated and that arcing from our high voltage
detection system will not occur in the conductive low pressure atmospheric environment, this test will be performed upon the payload by team PHIDO at the Embry-Riddle Atmospheric Physics Research Lab (APRL) in March
Centroid tests: Balance analysis performed by team PHIDO of the fully integrated payload
will be performed in the APRL in order to confirm that the mass centroid lies within the 1x1x1 inch cube requirement set by UC Boulder in March
Vibration tests: Wallops flight facility will perform vibration tests to confirm the integrity of our design shortly before flight.
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Kriszelda Menez
RockSat-C 2013
CoDR 51
Co
ns
eq
ue
nc
e
PS.RSK.1 PS.RSK.1 PS.RSK.2 PS.RSK.3
PS.RSK.2 PS.RSK.3
Possibility
PS.RSK Risk Prevention Plan
1 The whole system will not be functional if the batteries run out of power before data has been collected
Chose reliable NiMH 9V batteries, test within system
2 If connections are disrupted by vibration testing or launch conditions then data cannot be collected
Will perform vibration tests for the instrument and each of the systems
3 If it is unable to properly control the power to the detector system it will destroy our PMT
Will perform electrical tests to ensure proper operation
PS.RSK: Before
PS.RSK: After
RockSat-C 2013
CoDR 52
Co
ns
eq
ue
nc
e
DS.RSK.2
DS.RSK.1 DS.RSK.2
DS.RSK.1
Possibility
DS.RSK Risk Prevention Plan
1 The whole system will not be functional if the HV supply fails before data has been collected
Tests have been performed with HV power supplies within the housing
2 If the PMT breaks during vibration testing or launch conditions then data cannot be collected
Protect PMT with RTV11, perform vibrational tests on the system
PS.RSK: Before
PS.RSK: After
RockSat-C 2013
CoDR 53
Con
seq
uen
ce
OS.RSK.2 OS.RSK.1
OS.RSK.1 OS.RSK.2
Possibility
PS.RSK Risk Prevention Plan
1 Calibration will be disrupted if launch conditions exceed integrity of optical system structure
Optimized optical system in order to withstand launch conditions
2 The PMT will saturate if we cannot sufficiently reduce its light input to the acceptable range
Chose PMT that works best with other optical components to tailor transmittance
PS.RSK: Before
PS.RSK: After
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Kriszelda Menez
RockSat-C 2013
CoDR
Predicted Mass: 20+/-.1 lb (with necessary ballasts)
Predicted Volume: Will roughly occupy 265 in3 cylinder. Individually, the instrument’s devices will roughly occupy a total of 70 in3
Activation: Expect at-launch activation
Optical port is required, we are using around 800 V for high
voltage supply
55
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Molly Stagnitti
RockSat-C 2013
CoDR
Date Event
11/29/2012 Order Parts / Send in drawings for part to Machine Shop
11/30/2012 Critical Design Review (CDR) Due
11/30/2012 Receive microcontroller from Team Oasis
12/3/2012 Critical Design Review Teleconference
1/7/2013 Receive parts
1/8/2013 Start soldering pre-amp/discriminator
1/8/2013 Start to implement parts together
1/10/2013 Finish implementing parts
1/15/2013 Begin Testing on Subsystems
1/18/2013 Online Progress Report 1 Due
2/15/2013 Individual Subsystem Testing Reports Due
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RockSat-C 2013
CoDR 58
Date Event
2/18/2013 First Payment Due
2/28/2013 Finish construction of all parts, make sure testing is finalized
3/01/2013 Begin Payload Subsystem Integration
3/12/2013 Online Progress Report 2 Due
3/29/2013 Payload Subsystem Integration and Testing Report Due
4/08/2013 Final Payment Due
4/20/2013 Calibrate payload with canister
4/26/2013 First Full Mission Simulation Test Report Presentation Due
5/8-29/2013 Weekly Teleconferences
RockSat-C 2013
CoDR 59
Date Event
6/3/2013 Launch Readiness Review Presentations
6/12/2013 Travel to Wallops Flight Facility
6/13/2013 Visual Inspections at Refuge Inn
6/14-18/2013 Integration/Vibration at Wallops
6/19/2013 Presentations to next year’s RockSat
6/20/2013 Launch Day
RockSat-C 2013
CoDR 60
Estimated Travel Costs (4 people)
Expenses Total Costs
3 rooms ($120/day) $3600
Per diem (for 4 is $50/day) $2500
Transportation (Fuel expenses round trip)
$400
Launch Support through RockSat C Program: $12,000
RockSat-C 2013
CoDR 61
Estimated Instrument Costs
Item Cost
Photometer Detector $3700
Parabolic Mirror $315
Flat mirror for calibration system $2200
High voltage power supplies $500
Low voltage DC-DC converters $100
Ultra Violet interference filters $132
Machining and Materials $1200
Misc. printed circuit boards and electronic components
$500
Flight batteries $200
Total with Travel & Launch Support: $27,347
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Kriszelda Menez
RockSat-C 2013
CoDR 63
Find the center of gravity of whole structure
Areas of concern
Implementation of Team Oasis microcontroller with our electrical system
RockSat-C 2013
CoDR 64
Our next plans are to send in designs to the Machine Shop and come back in the Spring to implement them
Order parts before winter break
RockSat-C 2013
CoDR 65
0
5
10
15
20
25
0 50 100 150 200 250 300 350 400
% T
ran
smit
tan
ce
Wavelength (nm)
RockSat-C 2013
CoDR 66
Retrieved from http://www.espo.nasa.gov/solveII/implement.html
RockSat-C 2013
CoDR 67
Retrieved from http://tid.uio.no/ozone/plott/spectrum_thumb.png