Re: Orbital Towers.

From: Darin Sunley (
Date: Wed Mar 01 2000 - 14:09:09 MST

Eugene Leitl <> wrote:
To: <>

>I know nothing about tethers or orbital towers. However, what is wrong
>with hoisting rockets up to a tethered baloon (10..20 km height), and
>launching them from there?

The vast majority of the energy you spend to attain a stable orbit is in
building up your horizontal velocity relative to the ground, not fighting
gravity to gain 100+km of height.

You CAN launch from a couple km up. But it only buys you a vanishingly small
% of the total energy you have to spend.

Even if we HAD a tower right up to LEO, you would still have to spend approx
80% of the energy (something in this neighborhood anyways) to get from the
top of that tower to a stable orbit at that altitude.

Darin Sunley

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