[ExI] Inflatable tower could climb to the edge of space
hkhenson at rogers.com
Fri Jun 12 16:30:17 UTC 2009
At 05:00 AM 6/12/2009, Jeff Davis wrote:
>The structure will involve truly immense quantities of gas. Air is
>free, whereas generating hydrogen in the quantities needed would be
>costly. Exactly how costly needs a calculation.
From water, 48 MWh/t current, perhaps as low as 33 MWh/t for
advanced systems. Penny a kWh is $10/MWh, scale from there. A mole
of H2 occupies 22.4 l, a kg is 500 moles or 11.2 cubic meters.
Has anyone actually done an engineering analysis of an inflatable tower?
Hydrogen is close to 1/15 the molecular mass of air. Scale height of
air is ~7.6 km.
For a serious structure, drag from wind is going to be immense. Some
places on the equator have a fairly steady wind out of the east.
If the structure was 50 km high, the saving in delta v would be
50,000 = 1/2 gt^2
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?
More information about the extropy-chat