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Final Slide Concepts

Final Slide Concepts. March 26, 2009. 1. Lunar Surface Hazard Analysis. 2. Space Ball Structure Analysis. R. M pay *g. Bending Moment in Drive Axel Model as a thin circular rod R = 0.125m Aluminum 2024 Alloy σ = 220 MPa ρ = 2730 kg/m 3 Maximum loading conditions (8.3g)

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Final Slide Concepts

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  1. Final Slide Concepts March 26, 2009 [Cory Alban] [Mission Ops] [Locomotion] 1

  2. Lunar Surface Hazard Analysis [Cory Alban] [Mission Ops] [Locomotion] 2

  3. Space Ball Structure Analysis R Mpay*g • Bending Moment in Drive Axel • Model as a thin circular rod • R = 0.125m • Aluminum 2024 Alloy • σ= 220 MPa • ρ= 2730 kg/m3 • Maximum loading conditions (8.3g) • g = 8.3 * 9.80665m/s2 = 75.25m/s2 • Mpay = 1.529 kg • Minimum required radius: 1.17*10-8m • Torsion Stress in Drive Axel • Maximum Torque, T = 0.31 Nm • Minimum required radius: 1.10*10-4m • Design radius: 0.003m • Factor of Safety: 27 T [Cory Alban] [Mission Ops] [Locomotion] [Cory Alban] [Mission Ops] [Locomotion] 3

  4. Space Ball Structure Analysis R • Sphere Impact Analysis • Assume all kinetic energy converted to impact energy • Cruise Speed, v = 1.04m/s • Ball Mass, m = 2.435kg • Total Kinetic Energy, K = 1.317J • Impact Strength of Lexan, σ = 600 – 850 J/m • Minimum wall thickness: 1.55*10-3m • Pressure Vessel Analysis • Pressure, P = 101325 Pa (1atm) • Radius of sphere, R = 0.125 m • Maximum Stress of Lexan, σ = 75 Mpa • Minimum wall thickness: 8.4*10-5m • Design wall thickness: 3.82*10-3m • Factor of safety: 2.5 [Cory Alban] [Mission Ops] [Locomotion] [Cory Alban] [Mission Ops] [Locomotion] 4

  5. Design Concept: Ski Locomotion • Benefits • Passive Suspension System • Spring-like qualities • Vibration dampening • Makes use of regolith • While wheels require traction, ski slides over loose surface • Downfalls • Requires other systems • Separate propulsion system • Mechanism for turning • Additional friction drag • Either pushing or pulling skis through regolith • Possible ‘tipping’ failure • Rise onto a rock, pulling propulsion mechanism off lunar surface [Cory Alban] [Mission Ops] [Locomotion] [Cory Alban] [Mission Ops] [Locomotion] 5

  6. Completion of Mission Requirements [Cory Alban] [Mission Ops] [Locomotion] [Cory Alban] [Mission Ops] [Locomotion] 6

  7. Space Ball Overview Concept: By offsetting the center of mass inside the ball, a gravity moment causes the ball to roll. Size: Slightly larger than a basketball, the clear polycarbonate sphere has a diameter of 0.25m. Mass: The entire system weights in under 2.5kg! (2.435kg.) Power: The space ball runs on its own power supply nearly the size of a wristwatch battery. It is fully capable of achieving mission objectives on the lunar surface. [Cory Alban] [Mission Ops] [Locomotion] [Cory Alban] [Mission Ops] [Locomotion] 7

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