What is the difference in heat shield requirements and cosntructions for different demands?For example, in terms of Joules / Kg converted from kinetic and gravitational energy to heat:1. LEO reentry, 7km/s -> 0, =24.5MJ/kg2. Escape velocity reentry, 11km/s -> 0, = 60.5MJ/kg3. Aerocapture, 12km/s -> 11km/s, = 11.5MJ/kg.4. Aerobraking, 11km/s -> 7km/s, 26MJ/kgI assume in all these cases most of the heat is transferred to air molecules, and most of the rest is radiated away. Only a fraction is conducted away from the heatshield. Are the ratios similar for different types of reentry? Could the Spacex Dragon Heatshield, designed for Case 1 above, be used for Case 4? Can Case 2 be done as Case 4, followed by a cooling period, followed by Case 1?
Quote from: alexterrell on 10/25/2009 03:28 pmWhat is the difference in heat shield requirements and cosntructions for different demands?For example, in terms of Joules / Kg converted from kinetic and gravitational energy to heat:1. LEO reentry, 7km/s -> 0, =24.5MJ/kg = 2.65 M Calories / lb2. Escape velocity reentry, 11km/s -> 0, = 60.5MJ/kg = 6.5 M Calories / lb3. Aerocapture, 12km/s -> 11km/s, = 11.5MJ/kg = 1.24 M Calories / lb4. Aerobraking, 11km/s -> 7km/s, 26MJ/kg = 2.81 M Calories / lbI assume in all these cases most of the heat is transferred to air molecules, and most of the rest is radiated away. Only a fraction is conducted away from the heatshield. Are the ratios similar for different types of reentry? Could the Spacex Dragon Heatshield, designed for Case 1 above, be used for Case 4? Can Case 2 be done as Case 4, followed by a cooling period, followed by Case 1?If you convert to imperial for me I can help you out. I am too busy to do the conversion that is needed for me. I don't think metric.Danny Deger
What is the difference in heat shield requirements and cosntructions for different demands?For example, in terms of Joules / Kg converted from kinetic and gravitational energy to heat:1. LEO reentry, 7km/s -> 0, =24.5MJ/kg = 2.65 M Calories / lb2. Escape velocity reentry, 11km/s -> 0, = 60.5MJ/kg = 6.5 M Calories / lb3. Aerocapture, 12km/s -> 11km/s, = 11.5MJ/kg = 1.24 M Calories / lb4. Aerobraking, 11km/s -> 7km/s, 26MJ/kg = 2.81 M Calories / lbI assume in all these cases most of the heat is transferred to air molecules, and most of the rest is radiated away. Only a fraction is conducted away from the heatshield. Are the ratios similar for different types of reentry? Could the Spacex Dragon Heatshield, designed for Case 1 above, be used for Case 4? Can Case 2 be done as Case 4, followed by a cooling period, followed by Case 1?