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From: Henry Spencer <>
Subject: Re: Housing on the Moon and Mars
Date: Tue, 20 Feb 1996 15:49:57 GMT

In article <4g8qu6$> (David Erskine) writes:
>...On the Moon, towns sunk into hills or crater walls may be
>essential because of the heat of the Sun...

Actually, on either the Moon or Mars, it will be necessary to build
towns underground, because the radiation dose on the surface is too
high for long-term exposure.  On the Moon, several meters of soil will
be needed for adequate shielding.  The requirements are somewhat reduced
on Mars because its atmosphere helps.

>Fire is very serious problem, particularly with an oxygen rich
>atmosphere. If a fire breaks out in a room, the occupants, after leaving
>the room, must be able to seal it and vent the room's atmosphere to the
>outside to stop the fire.

Actually, that should be a last resort, because depressurization will
cause damage of various kinds.  Conventional fire extinguishers would
be the first line of defence.

>On the Moon and Mars, large amounts of pure metal may be available
>because there is no air to oxidise metal...

No, sorry, this simply isn't true.  While there is no air now, there
was abundant oxygen available during the formation of the two bodies,
just like during Earth's formation.  (Both water and CO2 are quite
effective oxygen sources at high temperatures.)  On the Moon and Mars,
just like on Earth, the metals will have started out locked up in
various chemical compounds; the presence or absence of an oxygen
atmosphere much later is irrelevant.
Space will not be opened by always                 |       Henry Spencer
leaving it to another generation.   --Bill Gaubatz |

From: Henry Spencer <>
Subject: Re: The High Frontier Revisited
Date: Mon, 25 Mar 1996 16:57:35 GMT

In article <4isdg7$> Thomas Kalbfus <> writes:
>...If a robot 
>were made 1 foot tall and capable of all the movement of a 
>human being...

Uh, you're making a big, big assumption here.  Not the size of the robots,
but the ability to build robots which mimic human mechanical capabilities.
We are far away from being able to do that.

The biggest problem with robotic lunar bases is that the robots will break
down.  Almost certainly, the best way to run such a base is to have a human
repair crew on hand.  In fact, the more sensible modern concepts for manned 
lunar bases tend to look much like that:  teleoperated robots for routine
chores like earthmoving and transportation, with humans doing the tricky
things like repairing the machinery when it breaks.
Americans proved to be more bureaucratic           |       Henry Spencer
than I ever thought.  --Valery Ryumin, RKK Energia |

From: Henry Spencer <>
Subject: Re: Colonization of the Moon vs Mars
Date: Mon, 8 Apr 1996 16:53:10 GMT

In article <4k0ml8$> Thomas Kalbfus <> writes:
>Which would be easier to colonize, the Moon or Mars? The Moon 
>lacks some vital ingredients necessary for life. The is no 
>water, no carbon, and no nitrogen...

Actually, this is much too strong a statement.  In particular, there is
good reason to suspect that there might be frozen volatiles at the lunar
poles, and Clementine provided some weak evidence in favor of this.

Statements that XYZ is *not* present on the Moon are premature.  We
understand the *average* lunar geology moderately well, but have little
information on extremes, and ore bodies are extreme cases by definition.

>...Mars on the other hand is far from Earth...

Actually, this is also much too strong a statement.  In terms of energy
costs, the surface of Mars is arguably closer than the surface of the
Moon (depending on what assumptions you make about aerobraking, use of
native resources, etc.).  Mars is farther away in terms of distance and
time, but although this does cause complications, they are secondary issues.

> is much easier to build an economic 
>justification for colonizing the Moon rather than Mars. The 
>exports from the Moon would just have to be of equal value as 
>the imports needed to sustain a human colony...

This is equally true of Mars.  It is hard to say which colony would need
a greater volume of imports.  Even if the Moon does have volatiles, Mars
certainly has a better supply of them.  On the other hand, teleoperation
from Earth will be very helpful on the Moon but is almost useless on Mars,
which means a Mars colony needs more manpower to get the same work done.
Americans proved to be more bureaucratic           |       Henry Spencer
than I ever thought.  --Valery Ryumin, RKK Energia |

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