nasa sli critical design review - wordpress.com · occurs around eye bolt hole •margin of safety...
TRANSCRIPT
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NASA SLI Critical Design Review UNIVERSITY OF ALABAMA IN HUNTSVILLE
CHARGER ROCKET WORKS
JANUARY 26, 2016
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Presentation Summary
UNIVERSITY OF ALABAMA IN HUNTSVILLE
•Project Overview
•Readiness and Design Summary
•Vehicle Analysis
•Mission Performance
•Recovery System
•Sub Scale Flight Analysis
•Payload Final Design
•Safety & Procedures
•Educational Engagement
•Project Management
•Questions
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Team Summary
UNIVERSITY OF ALABAMA IN HUNTSVILLE
•15 Total Team Members
•8 Mechanical Engineering Majors
•7 Aerospace Engineering Majors
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Technology Readiness Level
UNIVERSITY OF ALABAMA IN HUNTSVILLE
• Actual system “flight proven” through successful mission operations
• Actual system completed and “flight qualified” through test and demonstration (ground or flight)
• Prototype demonstration in a flight environment
• Payload ground test to verify functionality.
• Sub-scale model or prototype demonstration in relevant environment (ground or flight)
• Component validation through analysis and experiments as outlined in the component description sheets.
• Design concept and/or application formulated
• Basic design principals observed and reported
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Vehicle Concept of Operations
UNIVERSITY OF ALABAMA IN HUNTSVILLE
Launch (0 – 2.4 seconds)
Apogee Drogue Primary Fire (18.0 seconds)
Coast & Roll Phase
Drogue Main
600 ft. (73 seconds)
Landing (114 seconds)
Drogue Secondary Fire (19.0 seconds)
Main Parachute Secondary Fire (550 feet)
Main Parachute Primary Fire (600 feet)
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Vehicle Overview Vehicle Dimensions:
•Diameter: 6 inches
•Length: 119 inches
•Mass: 51.1 lbs
•Margin: 3 lbs
•Center of Pressure (CP): 89.82 inches
•Center of Gravity (CG): 73.43 inches
**All critical loads used for stress analysis are derived from the main parachute deployment with shock load of 24 g’s
UNIVERSITY OF ALABAMA IN HUNTSVILLE
Payload Briefing:
•Roll induction and counter roll
•Proportional Interval Derivative (PID) updates fin angle to actively control external fins
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CG CP
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Vehicle Interfaces
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Vehicle Interfaces Cont.
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Vehicle Analysis: Upper Airframe
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Upper Airframe Overview
UNIVERSITY OF ALABAMA IN HUNTSVILLE
• Design Overview • Fiberglass, 6” outer diameter, 36” long body tube with main parachute
storage. • Fiberglass, metal tipped, 4:1 fineness ratio nose cone. • X-Bee Radio/Antenova GPS chip combination GPS tracker mounted inside
nose via locally machined aluminum ‘L’ bracket. • Fiberglass coupler stores recovery avionics consisting of dual, 100%
independent Stratologger SL 100 altimeters, 9V batteries, switches, and locally 3-D printed mounting sled and switch mounts.
• Coupler also provides 6” interface with both upper and lower body tubes while assembled, and eye bolts fore and aft for parachute shock cords during recovery.
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Upper Airframe PDR Changes
UNIVERSITY OF ALABAMA IN HUNTSVILLE
• Dual pull pin assembly for altimeter systems • Altimeter power up check discernment • No change to construction, but changes pre-flight checklist
• Aluminum nose cone and coupler bulkheads • Finite element analysis using Patran revealed a 939 lbf load at center of main parachute side bulkhead upon deployment which translates to a max bending stress of 8.4 ksi • Stress tolerance of fiberglass bulkheads was indeterminate • Stress tolerance of aluminum are readily attainable and repeatable • Building in a Safety Factor (SF) of 2, the team obtained an additional Margin of Safety of 1.69% using the known ultimate tensile strength of aluminum • Will be locally machined at the University of Alabama in Huntsville
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Upper Airframe PDR Changes
UNIVERSITY OF ALABAMA IN HUNTSVILLE
Avionics Dual Pull Pin
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Upper Airframe PDR Changes
UNIVERSITY OF ALABAMA IN HUNTSVILLE
Aluminum Bulkhead
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Vehicle Analysis: Lower Airframe
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Lower Airframe Overview
UNIVERSITY OF ALABAMA IN HUNTSVILLE
• Design Overview • Fiberglass, 6” outer diameter, 53” long body tube • Components:
• Drogue parachute storage • Accommodates for payload section with attached control surfaces for roll
induction and counter roll • Forward lower bulkhead for recovery anchor • Fixed fin assembly with G10 fiberglass fins and Aluminum-2024 mounts • Motor section with Aerotech L2200 motor and casing • Tail cone assembly including snap ring for motor retention during thrust and
decent
Drogue Parachute Storage
Payload Section
Bulkhead
Motor Section Fixed Fin Assembly
Tail Cone Assembly
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Changes since PDR • Lower airframe bulkhead material changed from polycarbonate to
aluminum
• Drogue recovery retention system design changed to a single forward bulkhead attached to rocket body
Past motor retention design Updated forward bulkhead
retention design
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Lower Airframe Forward Bulkhead
UNIVERSITY OF ALABAMA IN HUNTSVILLE
• Aluminum was chosen over Polycarbonate due to it’s strength properties and light weight
• 0.25 inch thickness with 5.8 inch diameter
• Attaches to payload section via two 0.25 inch all thread rods
• Attaches to rocket body via four 8-32 screws
• Secures rocket to drogue parachute and payload to rocket
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Lower Airframe Bulkhead Analysis
UNIVERSITY OF ALABAMA IN HUNTSVILLE
• Max load of 706 lbf was used, with the load being determined from acceleration analysis
• Max stress of 18 ksi that occurs around eye bolt hole
• Margin of safety of 0.25 with built in factor of safety of 2
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Fin Subassembly Analysis Computational Fluid Dynamics Analysis:
•Pressure load concentrated on leading edge, i.e. the base of the fin bracket.
•Maximum pressure for this section is expected to range from 17 to 18.5 PSI.
Finite Element Modeling (FEM) Analysis:
•Maximum resultant force of approximately 1.61 lbf experienced by base
•Confident that no shear, internal stresses, or displacements will cause problems during ascension
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Tail Cone Assembly Analysis Compressive force from thrust stage on inner lip has potential to cause
failure
FEM Analysis:
•Shearing force on inner wall of thrust lip approximately 70 psi
•Supported by hand calculations
•Small shearing stress leads to confidence in success of design
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Airframe Component Testing
UNIVERSITY OF ALABAMA IN HUNTSVILLE
• Accomplished Testing • On hand altimeter testing was accomplished prior to subscale launch using a vacuum sealed container. Charge fire signals were sent at the moment of lowest detected pressure as expected. • GPS Tracker signal range was tested with interference from natural and man made obstacles. Average reception distance was 2.5 miles. • Subscale launches were the final successful test for both the altimeter and tracking systems. All four altimeters fired as expected, and both trackers transmitted their location to the team’s ground station. • Testing to be Accomplished • Spectrum analysis to determine if shielding should be installed in the coupler to prevent interference with the altimeter system from the GPS tracker. • Compression testing on tail cone to ensure material can withstand
compressive loads from thrust phase of flight • Lower Assembly drop test to ensure components maintain structural integrity
during impact
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Finalized Motor Selection • 75 mm diameter
• Mass gain through design maturity resulted in a higher impulse requirement to meet target apogee.
• Thrust curve per Open Rocket in Appendix
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Mission Performance
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Trajectory Curves
Time to apogee, max altitude
UNIVERSITY OF ALABAMA IN HUNTSVILLE
• Average weather conditions
• T/W: 9.42
• Rail Exit Velocity: 73.14 fps
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Stability Analysis
• Stability (off the rail): 2.17
• Burnout Stability: 2.97
• Launch angle of 5° applied to simulation
• No wind conditions
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Monte Carlo Analysis
UNIVERSITY OF ALABAMA IN HUNTSVILLE
• By randomizing variables, a more realistic apogee approximation can be determined.
• Wide range of apogee values due to variance applied to inputs
• Analysis/full-scale testing will shrink variance on inputs
• Standard deviation of Monte Carlo analysis will improve as confidence in variance of inputs shrinks
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Recovery System
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Drift Analysis
Model Assumptions:
• Apogee occurs directly above launch rail.
• The parachute opens over a set time period.
• The drift distance stops when the first component lands.
• Horizontal acceleration is based on relative velocity
• Drogue drag neglected once main is fully deployed
• Validated against flight data from similar rocket
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Drift Results •The graph on the left is a visual representation of the drift
•The table on the right displays the exact horizontal distances at landing
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Recovery System
UNIVERSITY OF ALABAMA IN HUNTSVILLE
Drogue Parachute Deployment: • Deployment at apogee
• Fruity Chute CFC-18 (Cd=1.5)
• Area = 1.77 ft^2
• Harness: 1 inch Tubular Nylon (50 ft)
• Connected between lower airframe bulkhead and avionics bay coupler.
Main Parachute Deployment: • Deployment at 600 ft AGL
• SkyAngle CERT-3 X-Large (Cd=2.59)
• Area = 89 ft^2
• Harness: 1 inch Tubular Nylon (50 ft)
• Connected between nose cone bulkhead and avionics bay coupler.
http://fruitychutes.com/ http://SkyAngle_CERT3.llc.homestead.com
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Descent Calculations
UNIVERSITY OF ALABAMA IN HUNTSVILLE
SECTION
Section Nose
Cone
Upper
Airframe
Lower
Airframe
Mass (lb) 3.741 10.243 25.51
Velocity (ft/s) 12.81 12.81 12.81
KE (ft-lbf) 9.53 26.09 65.12
•Terminal velocity under drogue: 120.76 ft/s
•Terminal velocity under main: 12.81 ft/s
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Staged Recovery System Testing • In order to test the dual deploy recovery system, there were actual components flown on the subscale that are being utilized on the full-scale rocket.
• Actual Components: • GPS Tracker
• Primary/Secondary
Altimeters
• Similar Components: • Drogue Parachute
• Main Parachute
• Recovery Harnesses
• Primary/Secondary
Black Powder Charges
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Sub Scale Flight Analysis
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Flight Data and Results
UNIVERSITY OF ALABAMA IN HUNTSVILLE 34
Vehicle 1 Vehicle 2
Forward Fins None Included
Stability Margin 2.18 2.18
Mass (wet) 7.47 lb. 7.62 lb.
Thrust to Weight 10.57 10.36
Both Vehicles
Half scale geometry
Mach: 0.46
Aerotech I284
Flight Data received by Stratologger CF
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Flight Data
UNIVERSITY OF ALABAMA IN HUNTSVILLE 35
Vehicle 1 Vehicle 2
Main Parachute did not deploy Successful launch and recovery
Time of flight: 70.35 seconds Time of flight 84.7 seconds
Max Vertical Velocity: 454.40 fps Max Vertical Velocity: 463. 41 fps
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Subscale Analysis
UNIVERSITY OF ALABAMA IN HUNTSVILLE 36
• Open Rocket coefficient of drag prediction from simulation.
• RockSim CD fine tuned to match ascent profiles.
• Analytical CD backed out from flight data:
𝐶𝑑 = −2𝑚𝑎 + 𝑔
𝐴𝜌𝑉2
Sources of Error: • Inconsistent altimeter data during the coast phase of the first flight.
• Wind conditions slightly different from flight 1 to 2.
Method 𝑪𝒅 of Vehicle 1 (No Fins) 𝑪𝒅 of Vehicle 2 (With Fins)
Open Rocket 0.532 0.517
RockSim 0.534 0.5295
Analytical (Measured Data) 0.64 0.5335
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Lessons Learned
UNIVERSITY OF ALABAMA IN HUNTSVILLE 37
Payload • Ensure wing wake doesn’t effect rear fins
Recovery • Parachute packing
• Verify dual deploy recovery system
• Verify ejection charge sizing procedures
Flight • Confirm simulated CD prediction
• Confirm stability – ensure safe flight
• Verify process to determine altitude
• Verify tracker mounting and functionality
• Optimize flight procedures for full-scale vehicle
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Subscale Testing and Results
Sub-Scale Flight Test Matrix
Type of Test Test Goals Results
Sub-Scale Flights
Verify the vehicle stability margin and flight characteristics
Successful (12/10/16)
Recovery System
Hardware
Test hardware that will allow for a single separation dual deploy setup
Successful (12/10/16)
Acceleration flight test
Ensure that avionics will survive launch forces
Successful (12/10/16)
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Payload Final Design
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Changes Made Since PDR • Power source changed to singular 14.8V battery, incorporating a voltage regulator for servos
• All-thread configuration changed from a single, central piece to two pieces holding forward and aft bulkheads
• Aft bulkhead changed from polycarbonate to aluminum
• Housing split into three sections for easier manufacturing
Final Dimensions • Length: 9.05” • Diameter: 5.82” • Weight: 4.251 lbs
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Payload Vehicle Integration
UNIVERSITY OF ALABAMA IN HUNTSVILLE
• Forward of motor case and aft of drogue recovery system.
• Attaches to body tube via two aluminum bulkheads.
• All thread holds bulkheads and payload as one piece.
• Installation
• Payload and bulkhead assembly is inserted into lower body tube.
• Bulkheads anchored to body tube with fasteners.
• Control rods attached to servos
• Fins attached to control rods with fasteners
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Fin Assembly • Held in place by two fasteners
• Machined aluminum fin connector
• Purchased servo arm extension
• Servo attached to housing with four fasteners
UNIVERSITY OF ALABAMA IN HUNTSVILLE
Payload Fin 1
Servo Connector Rod 2
Fin Bolts 3
Servo Extension 4
Servo 5
1
2
3 4
5
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Housing Assembly • Two aluminum bulkheads hold payload securely.
• Bulkheads fasten to body tube for solid attachment.
• myRIO, LiPO, and IMU all mount to plate in center of housing
UNIVERSITY OF ALABAMA IN HUNTSVILLE
0.25” Aluminum Bulkhead
1
Payload Housing 2
All thread 3
myRIO 4
LiPo 5
IMU 6
1
2
3
4 5
6
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Electrical Block Diagram
UNIVERSITY OF ALABAMA IN HUNTSVILLE
Li-Po Battery
myRIO
Voltage Regulator
IMU
Servo Wings
Rotational Data
Power Input/Signal Motion
Remove Before Flight Pin
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Payload Electrical Budget
UNIVERSITY OF ALABAMA IN HUNTSVILLE
• One hour pre and post flight
• myRIO on full power • IMU on low power • Servo off
• Flight
• myRIO on full power • IMU, full power on ascent • Servos on for 8 seconds
Realistic mAmps Hours Battery Drain
myRIO (pre-flight) 945.95 1 945.95
myRIO (flight/postflight) 945.95 1 945.95
Servo (during roll) 1300 2.00E-03 2.6
Gyro (pre-flight/post-flight) 8.00E-06 2 1.60E-05
Gyro (flight) 3.2 5.00E-03 1.60E-02
accel (pre-flight/post-flight) 8.40E-06 2 1.68E-05
accel (active) 4.50E-04 5.00E-03 2.25E-06
mAh 2105.21
Left over charge
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Control Surfaces • Constraints:
• Thickness < 12% • Symmetric • NACA Airfoil
• Decided to go with the NACA 0006
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Aerodynamics • Utilized 3D linearized finite wing theory
• Simulated rotation time for fixed angles of attack
• Proved that a roll and de-roll maneuver can be completed in alluded time
UNIVERSITY OF ALABAMA IN HUNTSVILLE
𝑎𝑐𝑜𝑚𝑝 = 𝑎0
1 − 𝑀∞2 +
𝑎0𝜋𝑒1𝐴𝑅
2
+ 𝑎0/(𝜋𝐴𝑅)
𝑎0 − 𝐿𝑖𝑓𝑡 𝐶𝑢𝑟𝑣𝑒 𝑆𝑙𝑜𝑝𝑒 𝑀∞ − 𝑀𝑎𝑐 𝑁𝑢𝑚𝑏𝑒𝑟 𝐴𝑅 − 𝐴𝑠𝑝𝑒𝑐𝑡 𝑅𝑎𝑡𝑖𝑜 𝑒1 − Span Efficiency Factor
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Controller
UNIVERSITY OF ALABAMA IN HUNTSVILLE
• PID Controller will regulate the fin angle to keep angular velocity constant
• myRIO will use MATLAB run the controller in Simulink
• Roll/Counter-roll should take approximately 5-8 seconds
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Safety & Procedures
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CRW Safety Commitment
UNIVERSITY OF ALABAMA IN HUNTSVILLE
•Training and communication are the key fundamentals for a successful safety program
•Safety Briefings keep team members informed and educated on safety topics relevant to upcoming activities
•Hazard, risk analysis, and Standard Operating Procedures used to instill good work practices and ensure all mitigation options are verified
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Failure Modes Analysis
UNIVERSITY OF ALABAMA IN HUNTSVILLE
Identification
•Sub-teams remain proactive and vigilant
Risk Assessment
•Weighed for probability and severity
Mitigation and Verification
•Means to reduce severity and/or likelihood are implemented
•Linked to test plan items for verification
Table 1: RAC
Probability
Severity
1
Catastrophic
2
Critical
3
Marginal
4
Negligible
A - Frequent 1A 2A 3A 4A
B – Probable 1B 2B 3B 4B
C – Occasional 1C 2C 3C 4C
D - Remote 1D 2D 3D 4D
E - Improbable 1E 2E 3E 4E
Table 2 Level of Risk and Level of Management Approval
Level of Risk Level of Management Approval/Approving Authority
High Risk Highly Undesirable. Documented approval from the MSFC EMC or an
equivalent level independent management committee.
Moderate Risk Undesirable. Documented approval from the facility/operation owner’s
Department/Laboratory/Office Manager or designee(s) or an equivalent
level management committee.
Low Risk Acceptable. Documented approval from the supervisor directly responsible
for operating the facility or performing the operation.
Minimal Risk Acceptable. Documented approval not required, but an informal review by
the supervisor directly responsible for operating the facility or performing
the operation is highly recommended. Use of a generic JHA posted on the
SHE Webpage is recommended.
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Personnel Hazard Analysis
UNIVERSITY OF ALABAMA IN HUNTSVILLE
Strategies
•Preparedness •Individual attentiveness •Training provided in Safety Briefings •Buddy system
Risk Assessment
•Weighed for probability and severity
Mitigation and Verification
•Means to reduce severity and/or likelihood are implemented •PPE and safety controls •Training
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Environmental Concerns
UNIVERSITY OF ALABAMA IN HUNTSVILLE
Effects of rocket on environment
•Hazardous materials
•Exhaust gas emissions
•Local ecology and wildlife
•Noise Pollution
Effects of environment on rocket
•Rain
•High winds
•Surrounding geography
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Launch and Assembly Procedures
UNIVERSITY OF ALABAMA IN HUNTSVILLE
Standardization •Standard Operating Procedure (SOP) format used for the subscale will be used to optimize full-scale flight procedures
Development
•Sub-teams develop step-by-step processes to perform at the launch site or in preparation
Review and Hazard Assessment
•All procedures are subjected to a peer review and hazard assessment
Simulation and Training
•A red team runs approved procedures in a controlled environment to verify accuracy
Implementation
•Finalized procedures are carried out under the supervision of the safety monitor and team mentor
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Safety Briefings • Weekly safety briefings focused on material pertinent to project phase
CRW Team Training
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Test Plans and Status
UNIVERSITY OF ALABAMA IN HUNTSVILLE
Test # Test Plan Status
T01 Test tracker in various environments to confirm
range Complete
T02 Ground testing of the charge size required to
successfully shear the Nylon pins and eject the
parachutes.
Completed successfully for
subscale
Full-scale testing planned for mid
Jan 2017
T03 System Test for timing mechanics Not yet complete
T04 Rotate payload about roll axis and look for fin
actuation
Awaiting parts – Testing planned
for the end of Jan 2017
T05 Remove power source to one of the servos,
observe results.
Awaiting parts – Testing planned
for the end of Jan 2017
T06 Place IMU on a flat table and calibrate each axis
of the accelerometer.
Place the IMU on a spinning table that is
rotating at a fixed rate to calibrate the gyros.
Calibration will be completed by
the end of January
T07 Subscale launch successfully completed on
December 10, 2016
Successfully Completed
T08 The CRW team has identified dates to launch
before FRR. Primary date is currently February
4, 2017 and secondary date of March 4, 2017
Not yet completed -- Primary date
is currently February 4, 2017 and
secondary date of March 4, 2017
T09 Ground test to verify payload response to
vehicle rotation Awaiting parts – Planned for end of
Jan 2017
T10 In-house compression test Awaiting parts – Planned for end of
Jan 2017
T11 Ensure GPS Tracker does not induce a charge on
ematches Test planned for last week of
January
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Information on Website
For the convenience of all team members, the following items will be located on the CRW team website:
•Material Safety Data Sheets
•Operators Manuals
•CRW Safety Regulations
•Safety Briefing slides
•Standard Operating Procedures
The Safety Officer will work to keep this information relevant and up to date
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Educational Engagement
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University of Alabama in Huntsville
Educational Engagement Schedule
Event Date Type of Engagemnt Anticipated Number of
Individuals Impacted
UAH Discovery Days October 29th Outreach: Direct Interaction 100
Girl's Science & Engineering Day November 5th Education: Direct Interaction 160
Girl Scouts STEM Fest November 12th Education: Direct Interaction 80
UAH Discovery Days November 19th Outreach: Direct Interaction 500
Society of Women Engineers: First
LEGO League QualifierJanuary 14th Education: Direct Interaction 400
James Clemens High School Mar-17 Outreach: Direct Interaction 1250
Bob Jones High School Mar-17 Outreach: Direct Interaction 1250
Science Olympiad Mar-17 Education: Direct Interaction 50
Boys & Girls Club Mar-17 Education: Direct Interaction 25
UAH Engineering Organization
PresentationsVaries Outreach: Direct Interaction 100
Additive Manufacturing Program Varies Education: Direct Interaction 25
Total Impacted 3940
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Educational Engagement Activities:
University of Alabama in Huntsville
Past Outreach Event Photos:
UAH Society of Women Engineers FIRST Lego League Qualifier • January 14th • SWE & FIRST Sponsored • Children ages 8-14 • 400+ individuals in attendance • Participants design and program an autonomous robot and compete to
complete a number of tasks to advance to the state level.
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Project Management
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Status of Requirements Verification
Number Source Requirement Statement Verification Method Status
V01 SLI The vehicle shall deliver a payload to
an apogee altitude of 5,280 feet above
ground level (AGL), but will not exceed
5,600 feet
Open Rocket simulations have
verified the design will obtain the
desired altitude
Complete
Full Scale Launch T08
V02 SLI The vehicle will carry a commercially
available, barometric altimeter to be
used for official scoring
Selection of Stratologger SL 100
Altimeters
Complete
R01 SLI All recovery electronics shall be
powered by commercially available
batteries
Selection of commercially available
CR123 batteries battery powered
electronics
Complete
S01 SLI Vehicle must be recoverable and same
day reusable without repairs or
modifications.
Selection of durable materials in
PDR, and adequate recovery system
based on max landing velocity of
13.76ft
s
Complete
V03 SLI The vehicle will have no more than
four sections during descent.
The vehicle design has three
sections during descent
Complete
V04 SLI Must be propelled by a single stage,
commercially available solid motor.
The vehicle design is single stage
utilizing an Aerotech L2200 motor.
Complete
UNIVERSITY OF ALABAMA IN HUNTSVILLE
For a full list of Requirements & Verifications, see CDR Document, Appendix D: Vehicle Verification Requirements
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Project Budget Summary
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Project Schedule – Spring 2017
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Questions?
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Appendix
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Tracking Assembly
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UNIVERSITY OF ALABAMA IN HUNTSVILLE
Black Powder Housing (4 Places)
Eye Bolt (2 Places)
Black Powder Terminal (4 Places)
All Thread (2 Places)
9 V Battery (2 Places)
Switch/Port Hole (4 Places)
Stratologger SL100 Altimeter (2 Places)
2”
14”
Coupler Assembly
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Avionics Bay Assembly
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UNIVERSITY OF ALABAMA IN HUNTSVILLE
Stratologger SL100 (Primary)
9V
Stratologger SL100 (Secondary)
9V
Primary BP
Charge
Secondary BP Charge
Switch
Switch
Primary BP Charge
Secondary BP Charge
Drogue Parachute Bay Charge Fired at apogee
(5,280 ft)
Avionics Bay Main Parachute Bay Charge Fired at 600 ft
Line of Redundancy
Bulkheads Rocket Nose
*Secondary 130% of primary
Charge Fired 1 sec after apogee
Charge Fired at 550 ft
Avionics Block Diagram
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Aerotech L2200 Thrust Curve
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Project Schedule – Fall 2016
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Milestone Review Flysheet
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UNIVERSITY OF ALABAMA IN HUNTSVILLE
Milestone Review Flysheet
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Milestone Review Flysheet
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UNIVERSITY OF ALABAMA IN HUNTSVILLE
Milestone Review Flysheet
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