[ExI] question re "honkin' big cannon" space launch

[Damien Broderick]

At 11:13 AM 2/28/2009 -0700, Jeff wrote:

>Fast forward, oh, eight or nine years, to the latest reprise of the
>space launch topic, and Paul Fernhout mentions "sky hooks" and a
>"space pier".  I asked Paul offlist about the "space pier", thinking
>he was joking, but no, he wasn't, and he provided me with a link(which
>I have since lost).
>
>On that website, I found a crude drawing depicting a horizontal
>launch/acceleration platform several tens of miles in length held
>aloft some tens of miles up by legs/struts.   Could have been fifty
>miles up, I don't remember exactly, but what I do remember is that
>there was no mention of no mention of "hypersonic acoustic shock" or
>whatever and it wasn't 100, 110, or 150 miles up, you know, up there
>in viable-orbit-land, which is to say thoroughly "out of the
>atmosphere".

If it's the classic space pier, it *was* 100 km up. Here's what I 
wrote in a Mars science museum installation some years ago:

======
NASA scientists Drs. Landis and Cafarelli have done the sums [on a 
hybrid skyhook-tower device]. It seems that an immensely tall tower 
could indeed be built. The stresses in a diamond tower with its 
mighty footings deep in rock would be compressive, squeezing 
downward, the contrary of that outward tension tearing at a space 
thread. Small shifts in the crust would put it at risk of toppling or 
buckling, so active computerized management would be necessary to 
ensure stability. Further calculations show that a blend of skyhook 
satellite and very tall tower might be the optimal mix, using less 
materials and cheaper to build. But these same technologies have 
suggested a quite different audacious scheme to Dr J. Storrs Hall, 
one of the few people to have devoted a lot of disciplined effort to 
exploring the prospects of nanotechnology. His notion is strange, but 
remarkably simple and perhaps elegant in the way of the Eiffel Tower. 
He proposes a Launch Pier a hundred kilometers tall, extending above 
all but the last of the atmosphere, and three hundred long.
             It would resemble the world's largest trestle, built 
from slender diamond-like towers marching beyond the horizon like 
impossibly tall spidery radio transmitters. At their top, a colossal 
rail structure would lead to an edge I can imagine base-jumpers 
lining up for months to jump off. The rails would carry magnetically 
levitated spacecraft, accelerating them smoothly for 80 seconds at a 
crushing but acceptable 10 gravities. Released at the end of their 
300 km run, spared the burden of carrying most of their own 
propellent, spacecraft would head for orbit along computer-specified 
trajectories, correcting their paths with exquisite changes of 
velocity from their conventional rockets.
             From the ground, you wouldn't be able to see the immense 
launch platform lost in the haze of air far beneath it. Perhaps you 
would only see a few of the great struts plunging upward into the 
blue. Sunlight, effectively undiminished, would shine through the 
lacy thing upon crops. There'd be no noise, except where great 
gantries and elevators carried their loads into the skies, powered 
not by expensive rocket fuel but by cheap electricity (which might 
well be generated from solar energy at the top of the trestle). How 
much would such a marvel cost to build? Hall claims it could be built 
today, using available technology and materials, although at 
exorbitant expense. With moderately early nanotechnology to spin the 
half million tonnes of struts, plus magnetic coils and electronics, 
that impossible price might plunge to $500,000,000, or more 
conservatively $10 billion. By comparison, 300 kilometres of 
superhighway today costs at least a billion dollars; building the 
Hubble Space Telescope, hoisting it into orbit and then repairing it 
took $3.2 billion; the International Space Station's bill will be 
more than $20 billion. The Apollo mission to the Moon cost $24 
billion in 1960 dollars.. but today its mighty Saturn launch vehicles 
have been dismantled and even their engineering plans were destroyed. 
Hall notes: `If an Apollo-style (and -cost) project could do for 
diamond what the original one did for electronics, we could build the 
tower in the next decade or so.= Operating costs could fall to $1 per 
kilogram lifted into orbit. Today=s costs using rockets are 10,000 
times higher.
             In short, a major push in developing molecular 
nanotechnology could pay off by reducing the cost of this dramatic 
launch platform into space--and provide us with all the other 
benefits of matter compilers almost as an incidental. Those benefits 
will probably include inexpensive consumer goods, perhaps including 
foods, clothing, safe terrestrial transport, shelter and computation. 
That implies a complete  and perhaps catastrophic shake-up in the 
global economy, as we shift from a world of scarcity to one of plenty 
within a brief period of time. During such an upheaval, will anyone 
be thinking seriously about exploring the Solar System and beyond? 
Yes--because even with the new opportunities for intelligent 
recycling that nanotechnology affords us, we'll want all the extra 
resources we can find. And space, in the form of asteroids, but also 
moons and planets, will be an abundant source of raw materials for a 
very long time, without the disturbing moral costs that should have 
troubled our colonizing ancestors.

==============

Damien Broderick