(2)

1. Lunar Lander Propulsion – Engine Specifications (4) (3) (1) (2) Stick is 6.5 feet high, same as a standard doorway Thaddaeus Halsmer, Propulsion

2. Lunar Lander Propulsion –fluid system diagrams HV01 HV01 High Pressure Helium Tank High Pressure Helium Tank SV01 SV05 SV03 SV04 SV01 REG REG CK01 CK01 SV02 SV02 CK02 CK02 RV01 RV01 MOV MOV F01 F01 H2O2 Tank H2O2 Tank HV02 HV02 100g and Large payload cases 10kg payload case Thaddaeus Halsmer, Propulsion

3. Lunar Lander Propulsion - Propellant/Propulsion system selection • Selection Criteria: • Thrust • min/max • throttling • Dimensions • Short and fat • Mass – minimize • Propellant storability • Purchase/development costs • High Reliability Figure X: Propellant mass vs. Isp trade Thaddaeus Halsmer, Propulsion

4. Lunar Lander Propulsion - Nozzle area ratio and mass optimization • Used CEA to compute Isp for given nozzle area ratio • All other inputs constant • Empirical nozzle mass equation • As area ratio, ε, increases Mnozzle increases, but Isp increases also • As Isp increases Mprop decreases for a given thrust and burn time • Wrote Matlab script that used Matlab CEA interface to compute multiple Isp’s for different area ratio’s and the corresponding Mprop and Mnozzle for a given thrust, and burn time • Results: Area ratio for minimum mass occurred at ~150, however this nozzle would be very large and little is gained above ~100 Thaddaeus Halsmer, Propulsion

5. Lunar Lander Propulsion – Isp analysis approach Fuel grain dimension definitions Thaddaeus Halsmer, Propulsion

6. Lunar Lander Propulsion – fuel grain and chamber sizing approach • Choose • Empirical value for initial fuel regression rate • Initial O/F ratio for optimum Isp • Initial propellant mass flow rate • Compute required burn surface area • Dimensions of fuel grains • Diameter is derived from burn surface area found from values in step #1 and chosen fuel grain geometry • Thickness is function of burn time and regression rate • Compute Chamber dimensions • a. Chamber dimensions approximated from fuel grain size and additional room for insulating materials Thaddaeus Halsmer, Propulsion