MINIMIZING LAUNCH MASS FOR ISRU PROCESSES

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MINIMIZING LAUNCH MASS FOR ISRU PROCESSES
Chris England, Jet Propulsion Laboratory Kevin
Hallinan, University of Dayton
Space Resources Roundtable VI Sponsored by the
Lunar and Planetary Institute http//www.lpi.usra
.edu Colorado School of Mines, Golden, CO Novemb
er 1-3, 2004
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Notional Figure of Merit for ELM
An illustration of a figure-of-merit function.
Equation based on a cost-related analysis, U.
Kentucky, Institute for Mining Minerals
Research.
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Issues
How can we best understand energetic processes
that are conducted in diverse, unfamiliar, and
severe planetary environments?
Energetic processes are chemical, thermal, and
mech-anical operations that incur substantial
energy changes (heat flow, temperature change,
chemical change, friction, etc.)
How do we evaluate proposed energetic operations
off the Earth? How does NASA avoid guessing at wh
at is best? What differences in planetary environ
ments impact the selection of energetic
operations? How can we help developers to evaluat
e their processes?
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The Team
University of Dayton Thermal analysis of aeronaut
ical energy systems. Optimization of subsystem an
d system efficiencies in aircraft.
Student and faculty participation.
Jet Propulsion Laboratory Process thermodynamics
for energetic systems. Chemical systems with subs
tantial heat requirements.
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The Second Law of Thermodynamics
Thermal processes incur Carnot-like limitations
that are not understandable from only First Law
considerations. Its like designing a fossil fuel
ed electrical power plant for 90 energy
efficiency. To find out what factors limit proces
s efficiency, we must understand the energy flow
in detail. Process synthesis works best when seco
nd law effects are understood.
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How can we best understand energetic processes
that are conducted in highly diverse, unfamiliar,
and severe planetary environments?
Understand the environment as it pertains to
energy flow. The Moon and Mars have radically dif
ferent heat rejection environments
Understand how the environment affects the
selection of operations and processes.
Heat rejection methods for the Moon and Mars may
differ. Understand the relationships among proces
s equipment, structure, and OM to energy and
cost. Energy analysis, equipment characterization
, resource characterization, mass assessment,
power assessment, cost, .
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How do we best evaluate proposed energetic
operations off the Earth?
Earth launch mass (ELM) as an appropriate
figure-of-merit. Understandable to sponsors. Can
be related to thermodynamic and other
engineering analysis. Has a direct relationship t
o cost. Determining energy and exergy efficiency
is an intermediate objective (as we shall
argue). Unified with process analysis, mass analy
sis, reliability, redundancy, etc.
If another FOM might work, please suggest.
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What differences in planetary environments impact
the selection of energetic operations?
Heat transfer and temperature environment.
Heat rejection on the Moon is by radiation.
More efficient to reject heat at high
temperature Heat rejection on Mars is by convecti
on and radiation. Heat recovery favorable. Mass
transfer and heat transfer environment.
Low gravity of the Moon changes some processes
Classification of solids may be easier than on
Earth. Heat and mass transfer rates that depend o
n gravity will vary.
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What differences in planetary environments impact
the selection of energetic operations?
Landing environment. Low gravity of the Moon ease
s mass requirements for landing equipment.
Atmosphere of Mars eases mass requirements for
entry and landing. Any other environmental featur
es we missed?
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How can we help developers to evaluate their ISRU
processes?
An understandable figure-of-merit
Develop a method of correlating processes and
operations with Earth launch mass.
A format that relates processes and operations
directly to Earth launch mass.
Solar power generation is a trivial example.
Nuclear power generation adds heat rejection
complexity. A table of processes and operations w
ith corresponding irreversibility factors, or
something.
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Ilmenite Reduction for Oxygen
(For illustration of some thermodynamic process
elements not a complete list)
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Notional Figure of Merit for ELM
An illustration of a figure-of-merit function.
Equation based on a cost-related analysis, U.
Kentucky, Institute for Mining Minerals
Research.
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The Dead State
On Earth, the reference state is associated with
the ambient environment. Lively argument continue
s on the Earths Dead State. Reference state for
energy availability on the Moon?
A nearly dead chemical state, a variable thermal
environment. Reference state for energy availabil
ity on Mars? A not dead chemical state with hyd
rological concentration of resources.
Both carbon monoxide and oxygen in the atmosphere!
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Summary
Energy analysis is used with process synthesis
and engineering analysis to minimize the cost of
ISRU. The optimization process that includes seco
nd law balances may be obscure to some.
Everything that is obvious was once obscure.
Doyle Brunson Differences among planetary bodies
may dictate different processes.
Mars and the Moon are different enough to
consider differing ISRU.