[amsat-bb] Re: Thought experiment ... Rockets and balloons

[Tom Williams]

Easy to check to a first order estimate - just calculate total energy by calculating  payload mass raised to orbital height (potential energy) and accelerated to orbital velocity (kinetic), then figure what fraction of that is associated with raising the 37km fraction of the way.  

Because of the v**2 term in the velocity, the height contribution probably wouldn't be much.

Tom



On Sep 18, 2013, at 1:01 PM, Rob <pabutusa at gmail.com> wrote:

> I'm not a rocket scientist but I have an active imagination .....
> 
> Thinking of a recent XKCD .... to achieve orbit .... the hard part isn't
> the altitude it's the velocity ....
> 
> Would there be any advantage (cost effective) carrying a launch vehicle say
> to 37KM ... think Red Bull Stratos .... and firing the engines there???
> 
> So you're already 37KM up .... there's a lot less atmospheric drag ....
> 
> This would be like a drop from a plane ... but even higher ....
> 
> Thoughts???
> 
> de KA2PBT
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