[ExI] Skylon as first stage.

[Eugen Leitl]

On Wed, Apr 20, 2011 at 07:52:39AM -0700, Keith Henson wrote:

> The question is cost, and that's almost all due to the high cost of
> rockets to get millions of tons of power satellite parts to GEO.

The question is not just cost (by the way, have a look at
http://www.fastcompany.com/1745113/what-happens-when-solar-power-is-as-cheap-as-coal )
the problem is EROEI.

When we're looking at kW/kg, we shouldn't forget that the 
kg is at ~Mach 25, and it came from the bottom of the gravity
well which taxes your EROEI -- unless it came from lunar material.
 
-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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