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Use of Lunar Volatiles in Chemical Use of Lunar Volatiles in Chemical
and Nuclear-Thermal Rocketsand Nuclear-Thermal Rockets
John F SantariusJohn F Santarius
April 30, 1999April 30, 1999
Lecture 41, Part 2Lecture 41, Part 2
Resources from SpaceResources from Space
NEEP 533/ Geology 533 / Astronomy 533 / EMA 601NEEP 533/ Geology 533 / Astronomy 533 / EMA 601
University of WisconsinUniversity of Wisconsin
2JFS 1999 University of Wisconsin
Chemical Rockets Are Well DevelopedChemical Rockets Are Well Developed
Saturn V launchSaturn V launch
(Apollo program)(Apollo program)
DC-X hover testDC-X hover test
(Single-stage to orbit)(Single-stage to orbit)
See Resources from Space Lecture 16 University of Wisconsin 3
See Resources from Space Lecture 32
Chemical and Fission-Thermal RocketsChemical and Fission-Thermal Rockets
Will Probably Remain Necessary for Planetary LaunchWill Probably Remain Necessary for Planetary Launch
JFS 1999 University of Wisconsin 4
Lunar Volatiles Provide Many Raw Lunar Volatiles Provide Many Raw Materials for Rocket FuelMaterials for Rocket Fuel
5JFS 1999 University of WisconsinSee Resources from Space Lecture 13
Example Chemical Rocket Fuels Example Chemical Rocket Fuels Available on the MoonAvailable on the Moon
Fuel Oxidizer Isp (s)Liquid propellantsHydrogen (LH2) Oxygen (LOX) 450Kerosene LOX 260Monomethyl hydrazine (MMH) Nitrogen tetroxide (N204) 310Solid propellantsPowdered Al Ammonium perchlorate 270
6JFS 1999 University of WisconsinSee Resources from Space Lecture 9
7JFS 1999 University of Wisconsin
Example Lunar Mission ProfilesExample Lunar Mission Profiles
From J.A. From J.A. Mulqueen, “Lunar Mulqueen, “Lunar Lander Stage Lander Stage Requirements Requirements Based on the Civil Based on the Civil Needs Data Needs Data Base,” Second Base,” Second Conf. On Lunar Conf. On Lunar Bases and Space Bases and Space Activities of the Activities of the 21st Century, 21st Century, NASA Conf. Pub. NASA Conf. Pub. 3166, Vol. 1, p. 3166, Vol. 1, p. 101 (1988).101 (1988).
8JFS 1999 University of Wisconsin
Approximate Approximate v’s in Earth-Mars Spacev’s in Earth-Mars Space
From P.W. Keaton, “A Moon Base/Mars Base Transportation Depot,” Lunar Bases and 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).Space Activities of the 21st Century (Lunar and Planetary Institute, Houston, 1985).
9JFS 1999 University of Wisconsin
Approximate Approximate v’s in Earth-Mars Spacev’s in Earth-Mars Space
From P.W. Keaton, “A Moon Base/Mars Base Transportation Depot,” Lunar Bases and 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).Space Activities of the 21st Century (Lunar and Planetary Institute, Houston, 1985).
10JFS 1999 University of Wisconsin
Key Thermal-Rocket EquationsKey Thermal-Rocket Equations
exi
f
v
v
m
mexp
Rocket equation
M M propellant flow ratepropellant flow rate
F F thrustthrust = M v = M vex ex
PPww thrust powerthrust power = ½ M v = ½ M vexex22
vvexex exhaust velocityexhaust velocity
MMpp propellant mass propellant mass
v=5.6 km/s
The Rocket Equation Can Be Used to The Rocket Equation Can Be Used to Find Propellant-to-Payload Mass RatiosFind Propellant-to-Payload Mass Ratios
02000
40006000
800010000
DvHm� sL0
20004000
60008000
10000ExhaustvelocityHm � sL
05101520
Propellant� Payload
05101520
Propellant� Payload
11JFS 1999 University of Wisconsin
v Requirements (km/s) forv Requirements (km/s) forSelected Missions and Launch LocationsSelected Missions and Launch Locations
12JFS 1999 University of Wisconsin
Earth-launch
Moon-launch
LEO 9.2 2.8L1(SE) 12.4 2.6LLO 13.4 1.9Mars 16.8 8.1
• Note: Many factors complicate Earth launch beyond this Note: Many factors complicate Earth launch beyond this simple analysis, and the related simple analysis, and the related v’s are optimistic.v’s are optimistic.
Propellant Requirements for a LH2/LOX Chemical Propellant Requirements for a LH2/LOX Chemical Rocket with 100-Mg of Payload and StructureRocket with 100-Mg of Payload and Structure
13JFS 1999 University of Wisconsin
Earth-launch
Moon-launch
LEO 670 Mg 86 MgL1(SE) 1500 Mg 78 MgLLO 1900 Mg 53 MgMars 4100 Mg 510 Mg
• Note: Many factors complicate Earth launch, and those masses are Note: Many factors complicate Earth launch, and those masses are optimistic. Space Shuttle technology requires ~2500 Mg propellant/100 optimistic. Space Shuttle technology requires ~2500 Mg propellant/100 Mg.Mg.
• Assumes exhaust velocity is vAssumes exhaust velocity is vexex=4.5 km/s.=4.5 km/s.
Propellant Requirements for a Nuclear Thermal Propellant Requirements for a Nuclear Thermal Rocket with 100-Mg of Payload and StructureRocket with 100-Mg of Payload and Structure
14JFS 1999 University of Wisconsin
• Note: Launching nuclear thermal rockets from Earth is Note: Launching nuclear thermal rockets from Earth is problematic.problematic.
• Assumes exhaust velocity=9.41 km/s, based on S.K. Assumes exhaust velocity=9.41 km/s, based on S.K. Borowski’s LANTR concept (see paper AIAA-97-2956).Borowski’s LANTR concept (see paper AIAA-97-2956).
Earth-launch
Moon-launch
LEO 170 Mg 35 MgL1(SE) 270 Mg 33 MgLLO 320 Mg 23 MgMars 500 Mg 140 Mg
15JFS 1999 University of Wisconsin
SummarySummary
• The Moon can serve as a supply depot of The Moon can serve as a supply depot of chemical rocket fuel for near-Earth space and chemical rocket fuel for near-Earth space and interplanetary travel.interplanetary travel.
• CaveatCaveat: cost versus benefit must be considered: cost versus benefit must be considered
– All LEO and beyond space locations require less All LEO and beyond space locations require less propellant mass for rockets launched from the Moon propellant mass for rockets launched from the Moon rather than from Earth, but acquiring lunar resources rather than from Earth, but acquiring lunar resources generally costs more than acquiring terrestrial generally costs more than acquiring terrestrial resources.resources.
