1. Team Member Travis Noffke Decelerator System
Parachute Characterization
Aeroshell Separation
System Integration
Hours: 104

2. Primary Goals Provide deceleration force to top of aeroshell
Clearance of unnecessary system components -Includes: Backshell Majority of separation system Misc. components
Minimize payload descent stability disruption
11/19/2008
Travis Noffke

3. Decelerator System
Mortar Slug
11/19/2008
Travis Noffke

4. Requirements
Deploy decelerator at altitude which allows for airship inflation prior to final separation and deployment
10 meter clearance between top aeroshell and leading payload within 5 seconds (Approximately 400 N of drag required)
Maintain stable descent of each payload component to respective deployment phase
10 meters
Payload Containment
11/19/2008
Travis Noffke

5. System Events F parachute drag Mortar fires deployment bag
Payload
V payload
V backshell
F parachute drag
Mortar fires deployment bag
Aeroshell separation mechanism fires
Parachute inflates
Deceleration on top aeroshell
Complete separation
11/19/2008
Travis Noffke

6. Process Geometry Selection Parachute Characterization
Sizing
Opening Forces
Material Selection
Conical Ribbon Parameters
Various Diameters
Loading
Mass Ratio
Ballistic Coefficient
Tensile Strength Comparison
11/19/2008
Travis Noffke

7. Canopy Canopy profile [1]: Conical Ribbon Geometric Porosity [1]: 30%
Diameter: m
Effective Surface Area: m2
Vent Area: m2
Maximum Oscillation [1]: degrees
[1] Knacke T. W., Parachute Recovery Systems Design Manual
11/19/2008
Travis Noffke

8. Drag Generation Drag vs. Altitude from 0 to 60 km Drag (N)
Altitude: km
Atmospheric
Density (ρ): kg/m3
v deploy: m/s
v terminal: m/s
c D:
Drag (N)
Altitude (km)
11/19/2008
Travis Noffke

9. Deployment Parachute Inflation Time (s) vs. Diameter (m)
11/19/2008
Travis Noffke

10. Velocity Effect Velocity After Line-Stretch Velocity (m/s)
Diameter (m)
11/19/2008
Travis Noffke

11. Opening Forces for Select Diameters
Opening Forces (N)
Diameter (m)
11/19/2008
Travis Noffke

12. Separation Mechanism Concept
Example: Pyrotechnic Fastener
Simplicity
Commonly used in spacecraft
One of several methods available
Pyrotechnic
Pneumatic Action
Loaded Spring
Etc…
[2] Nasa.gov
Separation Mechanism Concept
11/19/2008
Travis Noffke

13. Stability Geometric Centroid Post-Separation: 0.49 m from leading edge
r = 50 mm mm
Geometric Centroid Post-Separation: m from leading edge
Even Mass Packing
Stability Requirement: CG
Shedding vs. Buoyancy Force
11/19/2008
Travis Noffke

14. Material Selection Kevlar© 29 Highest strength-weight ratio
Superior tensile strength
Space tested
Used in heritage systems
Canopy
Riser
Extension Lines
Tenacity is measured as grams of breaking force per denier unit of yarn or filament size.
Tenacity (Gpd)
[3] Dupont.com
11/19/2008
Travis Noffke

15. Further Studies Detailed Design Separation System
Nominal functionality test
Drop testing
Parachute Decelerator System
Deployment Test
Drop Test
Stability Analysis
Test body flow measurements for appropriate Re
11/19/2008
Travis Noffke

16. Additional Information (Backup Slides)
Deceleration Method Trade Study
Rockets
Parachutes
Aero-control Surfaces
Complexity:
High
Low
Med
Cost:
Risk:
Efficiency:
Availability
Effectiveness
11/19/2008
Travis Noffke

17. Additional Information (Backup Slides)
Parachute Geometry Study
Characterization 
Conical Ribbon
Disc-Gap-Band
Reliability:
High
Mass:
Less
More
Average Oscillation Angle
±3°
±10 to 15°
Drag Coefficient Range
.5 to .6
.52 to .58
Opening Force Coefficient
1.05 to 1.3
1.3
 Performance Comparison
Conical Ribbon
Disc-Gap-Band
Reliability: +
Mass: -
Average Oscillation Angle:
Drag Coefficient Range:
Opening Force Coefficient:
11/19/2008
Travis Noffke

18. Single Conical Ribbon Parachute
Additional Information (Backup Slides)
Parachute Cluster Configuration Trade Study
Cluster
Single Conical Ribbon Parachute
Reliability:
High
Difficulty:
Med
Low
Redundancy:
Stability
High+
High-
Cost:
Mass:
Andy Welsh
11/19/2008
Travis Noffke

19. Rocket Assisted Separation
Additional Information (Backup Slides)
Parachute Avoidance Trade Study
Rocket Assisted Separation
Parachute Separation
Complexity:
High
Med
Cost:
Low
Risk:
Effectiveness:
Med-
Andy Welsh
11/19/2008
Travis Noffke

20. Additional Information (Backup Slides)
Derivations:
Newton’s Eqns. Of Motion
Second Law
11/19/2008
Travis Noffke

21. Additional Information (Backup Slides)
11/19/2008
Travis Noffke