1. Use of Lunar Volatiles in Chemical and Nuclear-Thermal Rockets John F Santarius April 30, 1999 Lecture 41, Part 2 Resources from Space NEEP 533/ Geology 533 / Astronomy 533 / EMA 601 University of Wisconsin

2. JFS 1999 University of Wisconsin 2 Chemical Rockets Are Well Developed Saturn V launch (Apollo program) DC-X hover test (Single-stage to orbit)

3. See Resources from Space Lecture 16 University of Wisconsin 3

4. See Resources from Space Lecture 32 Chemical and Fission-Thermal Rockets Will Probably Remain Necessary for Planetary Launch JFS 1999 University of Wisconsin 4

5. Lunar Volatiles Provide Many Raw Materials for Rocket Fuel 5 JFS 1999 University of Wisconsin See Resources from Space Lecture 13

6. Example Chemical Rocket Fuels Available on the Moon 6 JFS 1999 University of Wisconsin See Resources from Space Lecture 9

7. JFS 1999 University of Wisconsin 7 Example Lunar Mission Profiles From J.A. Mulqueen, “Lunar Lander Stage Requirements Based on the Civil Needs Data Base,” Second Conf. On Lunar Bases and Space Activities of the 21st Century, NASA Conf. Pub. 3166, Vol. 1, p. 101 (1988).

8. JFS 1999 University of Wisconsin 8 Approximate  v’s in Earth-Mars Space From P.W. Keaton, “A Moon Base/Mars Base Transportation Depot,” Lunar Bases and Space Activities of the 21st Century (Lunar and Planetary Institute, Houston, 1985).

9. JFS 1999 University of Wisconsin 9 Approximate  v’s in Earth-Mars Space From P.W. Keaton, “A Moon Base/Mars Base Transportation Depot,” Lunar Bases and Space Activities of the 21st Century (Lunar and Planetary Institute, Houston, 1985).

10. JFS 1999 University of Wisconsin 10 Key Thermal-Rocket Equations Rocket equation M  propellant flow rate F  thrust = M v ex P w  thrust power = ½ M v ex 2 v ex  exhaust velocity M p  propellant mass  v=5.6 km/s

11. The Rocket Equation Can Be Used to Find Propellant-to-Payload Mass Ratios 11 JFS 1999 University of Wisconsin

12.  v Requirements (km/s) for Selected Missions and Launch Locations 12 JFS 1999 University of Wisconsin Note: Many factors complicate Earth launch beyond this simple analysis, and the related  v’s are optimistic. Note: Many factors complicate Earth launch beyond this simple analysis, and the related  v’s are optimistic.

13. Propellant Requirements for a LH2/LOX Chemical Rocket with 100-Mg of Payload and Structure 13 JFS 1999 University of Wisconsin Note: Many factors complicate Earth launch, and those masses are optimistic. Space Shuttle technology requires ~2500 Mg propellant/100 Mg. Note: Many factors complicate Earth launch, and those masses are optimistic. Space Shuttle technology requires ~2500 Mg propellant/100 Mg. Assumes exhaust velocity is v ex =4.5 km/s. Assumes exhaust velocity is v ex =4.5 km/s.

14. Propellant Requirements for a Nuclear Thermal Rocket with 100-Mg of Payload and Structure 14 JFS 1999 University of Wisconsin Note: Launching nuclear thermal rockets from Earth is problematic. Note: Launching nuclear thermal rockets from Earth is problematic. Assumes exhaust velocity=9.41 km/s, based on S.K. Borowski’s LANTR concept (see paper AIAA-97-2956). Assumes exhaust velocity=9.41 km/s, based on S.K. Borowski’s LANTR concept (see paper AIAA-97-2956).

15. JFS 1999 University of Wisconsin 15 Summary The Moon can serve as a supply depot of chemical rocket fuel for near-Earth space and interplanetary travel. The Moon can serve as a supply depot of chemical rocket fuel for near-Earth space and interplanetary travel. Caveat: cost versus benefit must be considered Caveat: cost versus benefit must be considered – All LEO and beyond space locations require less propellant mass for rockets launched from the Moon rather than from Earth, but acquiring lunar resources generally costs more than acquiring terrestrial resources.