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

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

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

AAE450 Spring 2009 Matlab code for Leg Loads 4

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

AAE450 Spring 2009 Division PartMass (kg)Power (W)Size (m)Price ($) Power Batteries (m^3) Solar Panels2 1 m (dia) x.1 Communications CPU x.33 x ,000 to 200,000 Camcorder Receiver x.13 x.022 Transmitter x.135 x.022 Antenna x.1 x.5 Propulsion Structure (dia),.6 m tall Propellant m^3 Mass, Volume, Power used in Lunar Leg and Sizing Calculations 6

AAE450 Spring 2009 Mass, Volume, Power used in Lunar Leg and Sizing Calculations Attitude Thrusters7.3 x.1 (dia) system2.5 star sensor x.032 x rover x.4 x.4 Structure frame38 thermal control26-15 Fudge Factor finert0.4 TotalLander Fudge Factor added and considered in landing mass 7

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, g Duration Amplitude of Harmonic Oscillations at SC/LV Interface Frequency, Hz2 to 55 to 1010 to 15 Amplitude, g Duration (s)100 Mean Geometric Frequency (Hz)Level of Sound Pressure (dB) *Dnepr Users Guide-Reference 1 8

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

AAE450 Spring 2009 References  Dnepr_User_Guide.pdf Dnepr_User_Guide.pdf  pdf pdf 