[ExI] Inflatable tower could climb to the edge of space
deimtee at optusnet.com.au
Wed Jun 10 17:05:05 UTC 2009
>>From: extropy-chat-bounces at lists.extropy.org
>>[mailto:extropy-chat-bounces at lists.extropy.org] On Behalf Of
>>Sent: Tuesday, June 09, 2009 10:51 PM
>>To: ExI chat list
>>Subject: Re: [ExI] Inflatable tower could climb to the edge of space
>>I would think the main advantage of a big tower would be the
>>option of installing a linear motor launcher inside.
>Ja, actually I was thinking along the side. spike
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>extropy-chat at lists.extropy.org
If it supported itself though lifting gasses rather than inflated
pressure, you could
have a low stress structure.
I would think a long tethered sectioned tube, rising at an angle of 15
to 20 degrees, of sufficient
diameter that you can sling a linear motor underneath and still have
on the tether cables to keep everything straight.
This should give you over 100 km of accelerator length. If you pull 5
gees for that
long you should be up around 3 to 4 km/sec.
I haven't done the math for it but I think that would be enough for
launches. Certainly it would get you high enough to use a small
efficient motor to circularize
Given the height and volume I think you would need to use hydrogen as
the lifting gas.
If you started on top of a fairly high mountain you could drop the angle
of climb, make the tube
much longer and have a higher exit velocity, while still keeping most of
the travel up in the rarified air.
Spike, regarding your idea of pressurizing to 20 times atmospheric in a
vertical tube, air has a mass
of ~1kg/m3 at STP. The mass of your column of gas is going to be (very
roughly) 75 million tonnes,
with a footprint of over 100 tonne/m2.
I don't want to be near that balloon if it bursts. :)
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