Design and Launch of a Balloon Re-Entry
Vehicle for Near Space Experimentation
Mechanical Team:
Michelle Wilson
Nate Herrmann
Caleb Barnes
Electrical Team:
Mark Falknor
Adam Kelly
Brent Guenther
Advisors:
Dr. Joseph Slater
Dr. Mitch Wolff
Steve Mascarella
Dr. Ruby Mawasha
Dr. John Wu
Update Outline
• Introduction/Background
• Design Criteria
• Payload System
Improvements
• Release Mechanism
• Parachute Deployment
• Payload Geometry
• Launch Summaries
• Concluding Remarks
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Background
• Purpose:
– Exploration and
experimentation of near
space for scientific and
educational purposes
– Stable freefalling vehicle for
use by ILC Dover in Rapid
Eye Program
• Opens doors to industry
collaboration:
– Cornerstone Research
Group
– ILC Dover
– AFOSR/Sensors Directorate
– L’Garde
– Boeing
– Air Force Materiel
Command
Project Criteria
Improve Launch Readiness:
Balloon enclosure, Filling process, Connection integrity
Cut-down mechanism
Shape for stable freefall
Parachute deployment
3
Normal Configuration
New Configuration
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Balloon Enclosure
• Balloon Enclosure
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–
–
–
Enables easier, hands-free filling
Enables launching in higher winds
Allows more launches
Protects balloon during launch delays
• Results
– More balloons have been sent up by the current
team than any in the past
– Weather less of a factor
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Flow Meter
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–
–
•
Volume Prediction
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–
•
FMA 1844 Omega flow meter with totalizer
Poor factory calibration
Recalibration curve determined
Original MATLAB program used an inaccurate free-lift value
MATLAB program was rewritten using more accurate volume
prediction methods
Results
–
–
Tested and verified at multiple launches
Eliminated uncertainty in filling process
Flow Meter Reading vs. Actual
Volume
Flow Meter Reading (L)
•
Flow Meter
350
300
250
200
150
100
50
0
y = 1.3898x + 0.6251
R² = 0.9977
0
50
100
150
Actual Volume Obtained (L)
200
250
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Release Mechanism
•
Release Mechanism
– Primary release: servo
– Back-up release: nichrome wire
– Servo and nichrome release activated
remotely by user command
– Both systems tested in a vacuum chamber and
on dry ice
– Servo mechanism has been successfully flight
tested
Backup release: nichrome wire
Primary release: servo
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Payload Rigging Upgrade
• Components individually strength
tested in lab
• Springs integrated to slow the rate
of loading
• Tangling issues
– Swivels
– Spreader ring
• Launch simulation
Weight
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10
Parachute Deployment
• Design Specifications
– Light weight
– Powerful
– Reliable in -50°C and 6.7kpa pressure
– Redundancy
– Payload compatible
• Design Inspiration
– High powered model rocketry
• Current Deployment Tube
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–
–
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3” diameter cardboard tube
3/8” thick plywood plug
Male and Female PVC fixtures
Aluminum U-bolt and nuts
11
Parachute Testing
• Ground tests
– All successfully deployed the parachute
• Vacuum Testing - Containment Methods
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–
–
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PVC fixture with epoxy containment
Latex surgical tubing
FFFG ground to fine powder
Custom machine aluminum canister with
electrical tape containment
• 1.75 grams FFFG powder
• Conclusions from Vacuum Tests
– Slower burn rate
– Lack of air as heat transfer medium
– Expanding gases cool
• Self extinguishing effect
– Containment is the key
12
Payload Design
• Design Specifications
– Aerodynamically stable during freefall
– Low terminal velocity
– Light weight
• Design Inspiration
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–
–
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Nose cones
Missiles
Tension cones
NASA reentry vehicles
• Our Reentry Vehicle
– Hemisphere base
– Conic tail
– Effects of tail angle investigated
13
CFD Analysis for Payload Design
Modeling
•
•
•
•
•
•
15°, 25°, and 35° half-angle
Flow velocity: 55.8 m/s
Velocity inlet (55.8 m/s)
Pressure outlet (6910 Pa)
Air properties at 60k ft
Inviscid flow
Tests
• Pressure drag
• Turbulent wake
• Stability
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CFD Analysis - Wake
15° angle
25° angle
35° angle
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CFD Analysis – Drag
15° angle
21.6 N drag force
43.8 mph
25° angle
31.48 N drag force
36.3 mph
35° angle
68.1 N drag force
24.74 mph
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Launch 1: Summary
Goals
• Test balloon enclosure
• Flow meter
Results
• Successes
• Balloon Enclosure worked
• Payload was recovered
• Complications
• Under-filled balloon
• Winds shifted South
• Balloon filling reinvestigated
• Release Mechanism became a priority
17
Launch 2: Summary
Goals
• Test both release mechanisms
• Monitor temperatures in payload
Results
• Complications
– Trusted rigging components failed
– Tracking equipment failure
– Payload recovered after a month
• What was learned
– Release mechanism worked
– Payload rigging reconsidered
18
Launch 3: Summary
Goals
•
•
•
Test servo release mechanism again
Test parachute deployment system
Test “rip and go” launching system
Results
•
•
•
Successes
• Servo released
• First “rip and go” launch a success
• Onboard video obtained
• Payloads recovered 20 miles west of Marysville, OH
Complications
• Parachute did not deploy
• Release line tied a ‘magic knot’
What was learned
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• Thermal issues need to be addressed
Team Contributions
• Overall launch readiness
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–
–
–
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Recalibrated flow meter & volume prediction
‘Rip and go’ launch system
Payload rigging upgraded
Launch simulation
More launches
• Payload additions
–
–
–
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Release system
Parachute deployment
New payload shape
Improved payload capabilities
20
Future Work
• Build a working prototype of new payload system
–
–
–
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More stability analysis / testing
Implement payload components into vehicle geometry
Fall tested
Launch freefall payload
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Gantt Chart
22
Budget
Project Expenses
Flow Meter & Calibration
Balloon Enclosure
Release Mechanisms
Parachute Deployment
Payload Design
Total Launch Expenses
Miscellaneous Project Expenses
Total
$1,055.00
$753.58
$195.90
$220.00
$192.78
$2,146.00
$200.00
$4,763.26
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Thank You for Your Attention
Questions/Comments?
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