[ExI] Inflatable tower could climb to the edge of space

spike spike66 at att.net
Fri Jun 12 19:09:36 UTC 2009


> ...On Behalf Of hkhenson
> Subject: Re: [ExI] Inflatable tower could climb to the edge of space
> ...
> If the structure was 50 km high, the saving in delta v would be
> 50,000 = 1/2 gt^2
> 100,000/g -t^2
> t=101 seconds
> V=gt
> V = ~1 km/sec.
> so if you launched off the top of this thing, you could gain 
> about ten percent over a ground launch plus about five 
> percent for air drag.
> Anyone think this deserves more analysis?
> Keith

My numbers were coming up pretty similar to yours, except I was using about
a 25 km height tower starting on a mountain top with about a 3g
acceleration, t=40 sec, a = 30 m/sec^2, v = 1200 m/sec.

The increased payload comes out to greater than 15% however, because of the
way the rocket equation works.  To make this pay, we would need a fly-back
winged first stage.  After looking at the amount of steel necessary, I am
inclined to agree this notion is a long shot.


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