AAE450 Spring 2009 Kelly Leffel 3/26/09 Structures and Thermal Lunar Descent Phase Lander Integration Lander Thermal Control (Day) Kelly Leffel Structures.

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AAE450 Spring 2009 Kelly Leffel 3/26/09 Structures and Thermal Lunar Descent Phase Lander Integration Lander Thermal Control (Day) Kelly Leffel Structures and Thermal 1

AAE450 Spring 2009 Thermal Control Day System  MLI Blanket –Covers the outside of the lander, the propulsion system, and the space balls’ compartments (100 gram payload case)  Heaters –Used on the propulsion system and the space balls’ compartment  Cooling System –Aluminum Plate 0.1 m 2 Underneath communication equipment –Heat Pipes Ammonia working fluid –Radiators Used to radiate excess heat Kelly Leffel Structures and Thermal 2 Not to Scale

AAE450 Spring 2009 Thermal Control Total Kelly Leffel Structures and Thermal 3 100 gram payload10 kg payloadArbitrary payload MLI blanket2.35 kg2.38 kg21.4 kg Heaters0.5 kg0.45 kg34.1 kg Cooling System6.72 kg6.73 kg1.03 kg TOTAL9.57 kg9.56 kg56.53 kg

AAE450 Spring 2009 BACK-UP SLIDES Kelly Leffel Structures and Thermal 4 MLI Blanket Lander surface, propulsion system, and space balls’ compartments (100 g) 30 layers Aluminized Mylar (0.007 g/cm^2) Effective emissivity= 0.005 Q = e*(A)*sb*(Th^4-Tc^4) e = Effective emissivity = 0.005 A = Surface area (changes for each lander) sb = Stefan-Boltzmann constant = 5.67 *10^-8 J/K^4.m^2.s Th = Hot temperature (temperature in the sun) = 393 K Tc = Cold temperature (temperature in the lander) = 293 K Additional 0.4 kg on the 100 g case for the ball storage box

AAE450 Spring 2009 Kelly Leffel Structures and Thermal 5 Heat needed to be removed Assume 70% efficient equipment With 40 Watts required, 12 Watts of heat released Communication Equipment Heat 100g – 49 Watts 10 kg – 38 Watts Arbitrary – 282 Watts

AAE450 Spring 2009  Communication Equipment has a Max Temperature of 313 K, keep at 303 K as a factor of safety  Keep Lander Operating Temperature around 293 K  Similar Thermal Control as the OTV –Area of Plate : 0.1 m^2 –Aluminum (Al) thermal conductivity : 236 W/(m*K) –Al density: 2700 kg/m^3 –Thickness < AK(T 1 - T 2 )/q < 3.8 m (for both cases) Choose 0.5 cm ( 0.005 m) –Mass of plate = density * thickness * area = 1.4 kg Kelly Leffel Structures and Thermal 6 Aluminum Plate

AAE450 Spring 2009 Ammonia Latent heat of vaporization of Ammonia: 1371 kJ/kg Mass (100 g) = 0.061 kW * 450 sec /(1371 kJ/kg) = 0.02 kg Mass (10 kg) = 0.050 kW * 450 sec /(1371 kJ/kg) = 0.017 kg Aluminum Heat Pipes (100g) Volume needed to simulate P=1 atm : 0.02313 m^3 Choose pipe of 5 m long 0.00463 m^2 cross sectional area pi*r i ^2 = 0.00463 m^2 : r i = 0.0384 m, r o = 0.0394 m Mass = 2700 * pi * (r o ^2 – r i ^2) * length = 3.3 kg Kelly Leffel Structures and Thermal 7 Heat Pipes

AAE450 Spring 2009 Heat Pipe Continued  Aluminum (10 kg) –Volume : 0.01532 m^3, choose length = 5 m –0.00306 m^2 cross sectional area –pi*r i ^2 = 0.00306 m^2 : r i = 0.0312 m, r o = 0.0322 m –Mass = 2700*pi*(0.0322^2-0.0312^2)*5 = 2.7 kg  Radiators –Dissipate 61 and 50 Watts –Emissivity of 0.92 for white paint –Area of the radiators:0.1762 m^2(100 g) and 0.1444 m^2 (10kg) –Mass = 2.38kg(100 g), 1.95kg (10 kg) Kelly Leffel Structures and Thermal 8

AAE450 Spring 2009 Overall Numbers Kelly Leffel Structures and Thermal 9  100 gram ComponentMass (kg) Dimensions (m) MLI blanket2.35lays on equip Al plate1.40.005 x 0.1 m 2 Heat pipe2.65 m, Ø 0.0560 Radiators2.7 0.005 x 0.311 x0.311 Ammonia0.021- Heaters 0.5 0.005 thick

AAE450 Spring 2009 Kelly Leffel Structures and Thermal 10  10 kilogram ComponentMass (kg) Dimensions (m) MLI blanket2.38lays on equip Al plate1.40.005 x 0.1 m 2 Heat pipe2.515 m, Ø 0.0575 Radiators2.8 0.005 x 0.38 x0.38 Ammonia0.0215- Heaters 0.5 0.005 thick

AAE450 Spring 2009  Arbitrary Kelly Leffel Structures and Thermal 11 ComponentMass (kg)Dimensions (m) MLI blanket 21.4 lays on equip Al plate 1.40.5 x 0.1 m^2 Heat pipe 10.5312 m, Ø 0.1039 Radiators 220.5 x 0.81 x 0.81 m Ammonia 0.1727 - Heaters 1.03 0.005 thick

AAE450 Spring 2009 References  Ryan Nelson for Lander Dimensions  Adham Fakhry for MLI/hydrazine help  Ian Meginnis for heat pipe help  Spacecraft Thermal Control Handbook Volume I and II for Thermal Control data  Robert Manning for MLI effective emissivity Kelly Leffel Structures and Thermal 12

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