#7 July 1987
Section 184.108.40.206.007.of the Artemis Data Book
What does power generation on the Moon have to do with software? We'll
soon see. Perhaps the most commonly proposed source of power for an initial
Lunar Base whose requirements are in the 100-1000 kilowatt range, is a form of
fast compact nuclear reactor such as is being developed in the SP-100 Program for
space applications. Systems considered are thermoelectric, in-core
thermionic, and Brayton-alternator types. Rather than use precious water*
as a coolant or thermal transfer medium, we could use "NaK", liquid sodium /
potassium which is a good eutectic medium and can be wholly lunar-sourced.
* [Now that Lunar Prospector has since discovered water ice at both Lunar
Poles in 1998, it would be legitimate to use some of it in closed coolant
loops for this purpose. NaK, it seems, is nasty stuff, and we did not
realize that at the time of writing. - PK]
The usual reason for proposing the nuclear option is the need to have steady
power all month long. It is imagined by nuclear proponents that since the
Sun shines on the Moon for 14.75 days at a time (dayspan) alternating with
equal periods of darkness, a Lunar settlement that relied on solar power
would have to power-down to an ultra-inactive state of torpor during the
Having grown up in Eisenhower's Atoms-for-Peace era, I was naturally
ardently pro-nuclear in my youth. This frame of mind has long since been replaced by
the opposing prejudice that the only good nuke is a dead nuke or no nuke at
all. But however you feel about the question, please bear with me while we
take a second look at the solar route.
The advantages touted for solar power on the Moon are not to be ignored.
The collectors are easily made from lunar materials. Solar power is
intrinsically modular. A solar plant can be added to, cloned in the next
neighborhood, sized specially for industrial areas and so on. Solar power
makes a good neighbor and generates no "Danger: Off Limits" signs. On the
air less, cloudless Moon, the intensity of sunlight on the surface is steady and
much greater than on Earth.
But the night! But the night! chant those easily discouraged through O'Neill
on down. Yes, the night! Two considerations: energy storage and energy
The very nature of living conditions on the Moon suggest an elegant answer
to nightspan power generation. On the Moon, even with possible polar
permashade deposits [since confirmed in 1998], water will be a premium, a resource
dearly earned or made possible by costly imported hydrogen, a resource never
to be squandered. Water will be as precious, as sacred to the "Lunans" as
it was to the Fremen on Frank Herbert's Dune-world of Arrakis. We will want,
nonetheless, not just enough to make the life and industrial cycles work,
but a healthy reserve.
How do we bank this reserve? In the from of tanks of liquid hydrogen? In
the form of idle ice in tunnels beneath the city? That's like putting money
under the mattress. No, the water reserves can, and should, and must be put
to work in two ways. First it will be a justifiable investment in public
morale and in the psychological well-being of the inhabitants to allow for
some open water in parks and / or parkways. Why not recirculating fountains
with goldfish ponds? Why not a meandering trout and canoe stream? Beside
renewing and uplifting the spirits, such open double-duty storage will be a
strong symbol of security, a tongue stuck out at the parched surface of this
new / old world.
But the second "interest-earning deposit" banking possibility for water is
to tie it to the solar power cycle. During the long sun-rich energy-productive
dayspan, the solar power plant(s), sized comfortably above expected dayspan
power needs, is also put to work disassociating some of the water reserves
into hydrogen and oxygen. This could be done by high temperature catalytic
cracking, a much more efficient method than that of electrolysis. This may
not even require additional power if the waste heat generated by the solar
power production is sufficiently high in temperature to be put to work in
this way. That will depend on how well the solar power system's design can
be optimized to "bust" water as a design by-product.
Then comes the nightspan! The solar power system shuts down at sunset and
adjacent to it, modular banks of hydrogen / oxygen powered fuel cells ( such
as those designed by Westinghouse ) come to life, slowly recombining the
hydrogen and oxygen into pure water to refresh the city's systems and
generating considerable amounts of electricity in the process. The
contribution to the water purification-recycling burden is a not-minor
What are the advantages of this plan? It is clean, dependable, far less
liable to shut down, so modular that maintenance on individual units will
not noticeably interrupt the smooth flow of power. And above all, since a solar
system can be interspersed throughout the city, it will be far less
vulnerable to a breach whether by meteorite, accident, or willful sabotage.
The high modularity of this "hydro-solar" ( solar / water cycling fuel cells
) system also means that design improvements and breakthroughs can easily be
taken advantage of. One is not frozen into a premature technology.
Finally, the modularity of the hydro-solar system means the city can grow smoothly
and not in the spurts held hostage to construction of added large centralized
But this is still hardware, right? Right! So where's the "software"?
Well, our second consideration was to be nightspan energy usage. Not being an
energy systems engineer, I do not presume to estimate how much power the
hydro-solar plant would generate during nightspan as compared with dayspan.
This ratio will surely improve with system design and sizing. But I think
it safe to say and honest to advise that during the fortnight of darkness,
power available will be somewhat less than that available during the fortnight of
sunshine. There should be enough, however, to make it quite unnecessary for
the settlement to "hibernate" provided a whole new philosophy or approach is
taken to the design of production systems, operations, and enterprises.
On Earth, where energy supplies are taken for granted, energy eating
production facilities function around the clock, even in some cases seven
days a week. Now in any enterprise there are processes and tasks that use
more energy and those that use less ( e.g. inspection, wrapping, book work,
etc. ), and these are are usually done side by side by separate personnel.
For the Moon, it will be important for every prospective new industry to
totally redesign its manner of operation to sequentially separate, so far as
possible ( and here goodwill and repeated reexamination and rethinking will
be needed ) all its process elements into a higher energy-using portion that
can be done during the dayspan half of the month and a lesser energy-using
portion that can be saved for the nightspan period. This won't be easy, and
for many industries and businesses, the division will be quite unequal in
terms of man-hours involved. Once such a thorough and resourceful
precipitation of heavy and light tasks is made and the light portion comes
up short, it may serve the enterprise to consider if some of the operations
normally done by suppliers or outside contractors, or perhaps even by
entrepreneurs using one's by-products and waste materials could be
incorporated to fill in the nightspan man-hours budget and keep everyone
productive. This would be the preferred method of balancing the work load
through the month. If an enterprise still comes up short on the light-task
side of the equation, it could also explore diversification into an
unrelated appropriately sized light business to be activated when work is needed to
fill predawn dates.
Now in a city of any size, there is bound to be quite a variety of
activities, some energy-heavy, others energy-light, all needed to make the
economy purr. Before we go to the Moon, probable mix scenarios should be
thoroughly investigated over and over for various stages in the city-bound
settlement's growth, and productive operations and enterprise portfolios
Such a system will look and work differently than our business-as-usual.
And I predict one enormous fringe benefit: worker morale. For many people,
employed by such task-separating firms, the ho-hum of work-a-day routine
will get a twice monthly shot in the arm at sunrise and sunset as they switch
tasks, jobs, and duties usually but probably not always, in the same job
location. For example, a worker might cast iron on the sun-up dayspan dates
and make art crafts from slag during the sun-down nightspan dates. Or edit
by night and print by day. Or separate ores by night and refine them by
day. Or make tiles by day and lay them by night. The possible combinations are
endless and refreshing.
This system, tailored to a mode of power generation which does not ignore
lunar rhythms but harmonizes with them, will make its mark in lunar culture
and civilization, a mark that will be distinctive and enviable. But to
prepare for it, a lot of SOFTWARE homework can and must be done now.
Contents of this issue of Moon Miners' Manifesto