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

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

Decelerator System Mortar Slug 11/19/2008 Travis Noffke

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

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

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

Canopy Canopy profile [1]: Conical Ribbon Geometric Porosity [1]: 30% Diameter: 1.5 m Effective Surface Area: 1.749 m2 Vent Area: 0.018 m2 Maximum Oscillation [1]: 3 degrees [1] Knacke T. W., Parachute Recovery Systems Design Manual 11/19/2008 Travis Noffke

Drag Generation Drag vs. Altitude from 0 to 60 km Drag (N) Altitude: 8 km Atmospheric Density (ρ): 3.910 kg/m3 v deploy: 15 m/s v terminal: 12 m/s c D: 0.50 Drag (N) Altitude (km) 11/19/2008 Travis Noffke

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

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

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

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

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

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

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

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

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

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

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

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

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