1. AAE450 Spring 2009 Lander Sizing and Launch Vibrations Feb. 12, 2009 Earth Launch/Lunar Descent Phase Group 1 [Ryan Nelson] [STRC]

2. AAE450 Spring 2009 Structural Components of Legs on Lunar Lander  Previous mass = 4.30 kg for all legs  New mass = 1.65 kg for all legs –Length of legs cut in half –Safety factor of 1.3 –Assume 1 leg takes full load –Length of 0.5m per leg  Legs oriented at 18.44° from vertical  Legs initially retracted within the Lander 2

3. AAE450 Spring 2009 Volume and Considerations  Previous Volume = approx. 2.75m 3  Estimated New Volume = 2.22m 3  Future Considerations –Aluminum honeycomb cartridge in primary struts can help absorb compression loads. –0.89 m diameter footpads to stabilize Lander. –Eliminating skin can reduce structure mass by up to 10kg. 3

4. AAE450 Spring 2009 Matlab code for Leg Loads 4

5. AAE450 Spring 2009 Calculating for lunar Lander  Volume(V) = 1/3 * pi * R^2 * (H+h) – 1/3 *pi*r^2*h - Volume equation obtained directly from Kelly Leffel presentation (week 4) 5

6. AAE450 Spring 2009 Division PartMass (kg)Power (W)Size (m)Price ($) Power Batteries20 0.14 (m^3) Solar Panels2 1 m (dia) x.1 Communications CPU1-5.33 x.33 x.032100,000 to 200,000 Camcorder0.38 1000 Receiver1-1.3.48 x.13 x.022 Transmitter0.42-6.25.19 x.135 x.022 Antenna0.5-.1 x.1 x.5 Propulsion Structure1.75-.25 (dia),.6 m tall Propellant 75- 0.0458 m^3 Mass, Volume, Power used in Lunar Leg and Sizing Calculations 6

7. AAE450 Spring 2009 Mass, Volume, Power used in Lunar Leg and Sizing Calculations Attitude Thrusters7.3 x.1 (dia) system2.5 star sensor3.2-10.2.032 x.032 x.016400000 rover 31.5.4 x.4 x.4 Structure frame38 thermal control26-15 Fudge Factor 15.76875 finert0.4 TotalLander210.25-37.75 -Fudge Factor added and considered in landing mass 7

8. AAE450 Spring 2009 Launch Effects on Dnepr Payload  Vibration Loads –Longitudinal –Lateral  Acoustic Loads Amplitude of Harmonic Oscillations at SC/LV Interface Frequency, Hz5 to 1010 to 1515 to 20 Amplitude, g0.50.60.5 Duration103060 Amplitude of Harmonic Oscillations at SC/LV Interface Frequency, Hz2 to 55 to 1010 to 15 Amplitude, g0.20.5 Duration (s)100 Mean Geometric Frequency (Hz)Level of Sound Pressure (dB) 31.5125 63132 125135 250134 500132 1000129 2000126 4000121 8000115 *Dnepr Users Guide-Reference 1 8

9. AAE450 Spring 2009 Additional Vibration Analysis  Structural stiffness should ensure values of fundamental frequency of Spacecraft are no less than 20 Hz in longitudinal and 10Hz in lateral.  Dynamic Loads –8.3g max in longitudinal direction –1g max in lateral direction *Dnepr Users Guide-Reference 1 9

10. AAE450 Spring 2009 References  http://snebulos.mit.edu/projects/reference/launch_vehicles/DNEPR/ Dnepr_User_Guide.pdf http://snebulos.mit.edu/projects/reference/launch_vehicles/DNEPR/ Dnepr_User_Guide.pdf  http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070031872_2 007031894.pdf http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070031872_2 007031894.pdf  http://www.apollosaturn.com/Lmnr/descent.htm http://www.apollosaturn.com/Lmnr/descent.htm 10