2002 non-fiction: George Dyson, son of Freeman, recounts what can be
told of the history of Project Orion, a plan to propel spacecraft with
nuclear explosions.
A great deal of the work done for the project is still
classified, which seems odd until you realise that it deals with the
construction of shaped-blast nuclear explosives, and with building
things that can stand up to the results. I certainly learned some
practical details from this book, and I wasn't wholly ignorant of
nuclear weapons design when I started.
The project's real problems were political, of course, but not the
obvious politics: needing nuclear bombs meant there had to be military
involvement, but the military couldn't readily come up with a use for
a 4,000-ton manned spacecraft, especially once unmanned observation
satellites and ICBMs become possible, and couldn't justify trips
beyond the Moon. Meanwhile, NASA was very interested in exploring the
solar system, but, well, nuclear bombs; indeed, one of the concerns
about building small craft was that it would necessarily mean
developing and building huge numbers of extremely reliable small
nuclear weapons. As the USAF was gradually pushed out of any presence
in space, chemical rockets just seemed more politically acceptable
even if they had vastly inferior performance.
Fallout was a problem too, of course; in the glory days of atmospheric
nuclear testing, a single launch wouldn't add much in proportion, but
that was still a fair amount (probably about ten premature deaths'
worth world-wide, to add to the thousand or so from other
detonations). Mind you, the fallout is fairly constant per launch,
since larger vehicles can use more efficient and cleaner bombs, which
is an argument for some of the really massive concepts…
Because the project never got as far as an actual nuclear test –
though miniature flight models running off high explosives showed the
soundness of the basic concept – one doesn't know what other problems
would have arisen. One of the major difficulties was clearly going to
be getting the bombs reliably into place from ship to detonation area,
with a blast rate of something like one per second: through a hole in
the shock absorber? Round the edge (which lets you have multiple
launchers), with a rocket to point it in the right direction before it
goes off?
Orion does remain the only space drive in current theory, including
all sorts of concepts involving fusion that certainly aren't buildable
yet, that would produce both high thrust and high specific impulse.
But if you've ever wondered what the Manhattan Project guys did after
the war, this is a big part of it. The original idea came from
Stanislaw Ulam, for example; Feynman (who'd casually invented a
NERVA-style reactor/hydrogen rocket concept) ran away at speed from
what seemed at first as though it might be another all-out project
like Manhattan. Bethe, Kantrowitz, and even von Braun were
peripherally involved.
This is a pretty crunchy book which goes into engineering details,
including the proposed armament of the military version:
Casaba-Howitzer, a nuclear shaped charge firing a narrow jet of
high-speed, low-density plasma, to be ejected from the craft and
detonated while it was pointing at the enemy. You should know at least
the basics of how nuclear weapons work before plunging in, though
Wikipedia has sufficient information.
Dyson is not an inspiring writer, but the text flows well enough, even
though the people often come over as a bit two-dimensional; for the
most part their lives outside the project are dismissed in a few
words. This is principally an account of the various directions
research took, and secondarily of the efforts made to get a useful
level of funding for the project.
An appendix lists the titles of the various papers written as part of
the project (though in many cases they're still classified).
Stability and Control of Space Vehicle. A Note on Maximum Opacity.
Stability of Motion Induced by Blast. The Vapor-Pressures of
Refractories and Their Fugacities Under Very High External Pressures.
And… Betelgeuse.
You know, there's material for a 1950s space horror story right
there.
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