[ExI] Launching Satellites from Airplanes DARPA

[spike]

>... On Behalf Of Eugen Leitl
Subject: Re: [ExI] Launching Satellites from Airplanes DARPA

On Mon, Nov 07, 2011 at 06:20:54PM -0800, spike wrote:

>> My own experience with it is that the problem doesn't scale down very
well.
> Every design I have derived has the cost per kg to LEO increasing 
> dramatically once the total payload goes much below 1000 kg.  I am 
> cheering wildly for anyone who can get those costs down.

>...A ton to LEO can go a long way.
https://secure.wikimedia.org/wikipedia/en/wiki/SMART-1

Agreed, but my own favorite idea for a payload is only a few tens of grams.


My best efforts at a very small rocket yielded a puzzling outcome: once you
get much below about a ton, the rocket mass and cost don't go down much
more.  It takes about the same rocket to hoist 1 kg as it takes to hoist
100.  At some point, the flight controls problem doesn't scale down, rather
it starts to scale up.  Smaller rockets take more computing power to keep
them flying pointy-end-first: the feedback loop needs to be faster.

spike