1. AAE450 Spring 2009 Final Slides Lunar Lander Structure April 9, 2009 Lunar Descent Phase Group [Ryan Nelson] [STRC] 1

2. AAE450 Spring 2009 Basic Frame Design  Drivers in frame mass –Total Lunar Lander (LL) mass at lunar touchdown –Volume of LL  Shape: Conic Frustum –Stores all Lunar Lander subsystems while minimizing volume  All frame components hollow –Small leg diameter allows for storage within side supports prior to lunar touchdown Schematic of frame listing components 2

3. AAE450 Spring 2009 Backup Slides (Mass/Volume) Lunar LanderVolumeHeightTop DiameterBottom DiameterMass 100g1.05 m 3 1.0 m 1.3 m11.44 kg 10kg 1.15 m 3 1.1 m1.0 m1.3 m19.97 kg Large 14.33 m 3 2.0 m2.4 m 3.6 m 104.86 kg 3

4. AAE450 Spring 2009 Backup Slides (Frame Design)  Thickness of all frame components varies –First mode of failure (factor of safety = 1.5) –Payload case  Cross sectional shape is circular or rectangular for all components  0.5 mm magnesium skin place around Lunar Lander frame –Micrometeorite protection –Thermal protection 4

5. AAE450 Spring 2009 Backup Slides (Floor Supports)  Support a majority of landing loads  Thickness altered until load is supported  Hollow Rectangular Cross section –Moment of Inertia –Bending Stress acting on beam 5

6. AAE450 Spring 2009 Backup Slides (Side Supports/Legs)  First mode of failure is buckling –K=0.5 for side supports (both ends fixed) –K=2.0 for legs (one end is free to move) –Hollowing the rod decreases moment of Inertia and critical load F cr = 6

7. AAE450 Spring 2009 Backup Slides (Side Supports/Legs)  Compression failure occurs after buckling for both side supports and legs –Despite small cross sectional area –Compression failure  Top, Bottom, and Engine Support rings all designed to have same cross sectional dimensions 7

8. AAE450 Spring 2009 Backup Slides (Cross Sectional Dimensions) 100g Payload Case Structural ComponentCross sectional shapeOuter DimensionsThickness Outer RingCircular10 cm Diameter4mm Engine Support RingCircular10 cm Diameter4mm Rectangular Floor SupportsRectangular10 cm Height, 6 cm Width6mm Side SupportsCircular10 cm Diameter2mm Top RingCircular10 cm Diameter4mm LegsCircular6 cm Diameter3mm 10kg Payload Case Structural ComponentCross sectional shapeOuter DimensionsThickness Outer RingCircular10 cm Diameter5mm Engine support RingCircular10 cm Diameter5mm Rectangular Floor supportsRectangular10 cm Height, 6 cm Width7mm Side supportsCircular10 cm Diameter2mm Top RingCircular10 cm Diameter5mm LegsCircular5 cm Diameter3mm 8