Use of Lunar Volatiles in Chemical and NuclearThermal Rockets John F Santarius April 30, 1999 Lectur

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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
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Chemical Rockets Are Well Developed
Saturn V launch (Apollo program)
DC-X hover test (Single-stage to orbit)
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See Resources from Space Lecture 16
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Chemical and Fission-Thermal Rockets Will
Probably Remain Necessary for Planetary Launch
See Resources from Space Lecture 32
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Lunar Volatiles Provide Many Raw Materials for
Rocket Fuel
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See Resources from Space Lecture 13
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Example Chemical Rocket Fuels Available on the
Moon
See Resources from Space Lecture 9
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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).
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Approximate ?vs 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).
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Approximate ?vs 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).
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Key Thermal-Rocket Equations
Rocket equation
?v5.6 km/s
Mp ? propellant mass

• M ? propellant flow rate
• F ? thrust M vex
• Pw ? thrust power ½ M vex2
• vex ? exhaust velocity

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The Rocket Equation Can Be Used to Find
Propellant-to-Payload Mass Ratios
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?v Requirements (km/s) forSelected Missions and
Launch Locations

• Note Many factors complicate Earth launch beyond
  this simple analysis, and the related ?vs are
  optimistic.

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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 vex4.5 km/s.

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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 velocity9.41 km/s, based on S.K.
  Borowskis LANTR concept (see paper AIAA-97-2956).

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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.