None the less, I would recommend his book 'The Case for
Mars'. If nothing else, reading the book should give you some idea as to
what we are up against. Zubrins 'Case for Mars' has probably done more to
wreak the 'High Frontier' than all else combined. And "Entering Space" devotes even more pages to a patient explanation of how everything O'Neill ever said was wrong. I've since learned that one reason for this hostility is that apparently devotees of Mars took some of O'Neill's comments regarding the relative disadvantages of planets as locations for settlement as adirect attack. When lashing out at High Frontier, they feel that they're only counter-attacking. The unfortunate situation is that we can't very well comment on the advantages of settlements in orbit without pointing out disadvantages of the alternative. Some of my own criticisms of Zubrin's criticisms can be found here: http://members.aol.com/oscarcombs/case_spc.htm#Robert_Zubrin http://members.aol.com/oscarcombs/spacsetl.htm#zubrin
Mike Combs
Zubrins estimate of lunar material launch costs (1/10,000th current price)
is probably about right, for the first ten years of operations. When you
consider the cost associated with setting up the moon base and all of the
necessary hardware in HEO, $4/kg is about right for the first 5-10 years,
assuming that the mass driver is on-line 100% of the time. The main points
that he missed are as follows:
million tonnes, 300-400 times lower than Zubrins mass estimate. A fully
shielded space manufacturing facility, capable of producing several SPS
satellites per year, would be in the few 100,000's of tonnes range,
shielding included. Even if all of Zubrins pessimistic assumptions were
true, the SMF would still produce enormous returns within a few years.
2) 1/10,000th current launch costs ($4/Kg) is easily cheap enough to
allow economic production of SPS satellites.
3) Plants are relatively hardy to radiation. Solar flares of the
variety that kill crops, do not occur frequently. We would expect to lose
only one harvest every 10 years or so, even assuming that the crop modules
are poorly shielded.
4) Mirrors in space can be as thin as foil, and support structures,
would weigh very little. The mirrors can be not rotating and would never
experience forces exceeding 1/1000th of a gravity.
Tony
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Two last nitpicks with him, then I'll try to shut up.
class. I objected to that, but then he brought it up again in the fusion
class and all was well. But then he skipped forward to controlled fusion
rockets -- "if we're going to be using fusion we might as well be using this",
ignoring the important point that controlled fusion doesn't exist yet, while
bombs are mature technology. Actually he seems to depend heavily on fusion
coming around real soon now -- it popped up in Jovian colonization. "All that
hydrogen." (Tangent: I hadn't seen analysis of radiation hazards in the
Jovian system before. So much for the Europan colony... if we broke through
the ice looking for life, would we kill it?)
He's also pretty strongly attached to the idea of aliens being out there,
whereas Savage (like me) believed probably there weren't any (else we wouldn't
be here) and I think O'Neill was agnostic. This is worth a nitpick because of
a weird argument:
We don't see diamondoid nanotech from aliens floating around.
I believe aliens are out there.
Therefore diamondoid nanotech must not be possible.
I don't think he'd appreciate a twist:
We don't see signs of life out there, ships cruising around.
I believe aliens are out there.
Therefore it's not possible for life to spread to visible levels.
But of course he does believe in spreading! Must be stealthy.
Not that I think Drex-tech is any certainty, but the argument seemed weird.
-xx- Damien X-)