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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. Chemical Rockets Are Well Developed. DC-X hover test (Single-stage to orbit).
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Use of Lunar Volatiles in Chemical and Nuclear-Thermal RocketsJohn F SantariusApril 30, 1999Lecture 41, Part 2Resources from SpaceNEEP 533/ Geology 533 / Astronomy 533 / EMA 601University of Wisconsin
Chemical Rockets Are Well Developed DC-X hover test (Single-stage to orbit) Saturn V launch (Apollo program)
See Resources from Space Lecture 16 3 University of Wisconsin
Chemical and Fission-Thermal Rockets Will Probably Remain Necessary for Planetary Launch See Resources from Space Lecture 32 4 University of Wisconsin JFS 1999
Lunar Volatiles Provide Many Raw Materials for Rocket Fuel 5 See Resources from Space Lecture 13 JFS 1999 University of Wisconsin
Example Chemical Rocket Fuels Available on the Moon See Resources from Space Lecture 9 University of Wisconsin JFS 1999 6
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).
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).
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).
Key Thermal-Rocket Equations Rocket equation M propellant flow rate F thrust = M vex Pw thrust power = ½ M vex2 vex exhaust velocity v=5.6 km/s Mp propellant mass
The Rocket Equation Can Be Used to Find Propellant-to-Payload Mass Ratios 11 JFS 1999 University of Wisconsin
v Requirements (km/s) forSelected Missions and Launch Locations • Note: Many factors complicate Earth launch beyond this simple analysis, and the related v’s are optimistic. 12 JFS 1999 University of Wisconsin
Propellant Requirements for a LH2/LOX Chemical Rocket with 100-Mg of Payload and Structure • Note: Many factors complicate Earth launch, and those masses are optimistic. Space Shuttle technology requires ~2500 Mg propellant/100 Mg. • Assumes exhaust velocity is vex=4.5 km/s. 13 JFS 1999 University of Wisconsin
Propellant Requirements for a Nuclear Thermal Rocket with 100-Mg of Payload and Structure • 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). 14 JFS 1999 University of Wisconsin
Summary • 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 • 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.