Re: VTVL?

Rand Simberg wrote:
On Mon, 30 Jul 2007 12:42:37 +1000, in a place far, far away, Sylvia
Else <sylvia@xxxxxxxxxxxxxxxxxxx> made the phosphor on my monitor glow
in such a way as to indicate that:

Russell Wallace wrote:
In discussion about the winged flyback strategy for reusable first stages, it's been remarked that when what you want to do is climb out of the atmosphere, a simple vertical takeoff rocket stage with no wings or airbreathing engines is the most efficient. The arguments for that make sense to me.
Climbing out of the atmosphere is really a secondary goal. The primary goal is reaching orbital speed. The problem with a vertical launch is that it imparts a velocity that is perpendicular to the one needed. The result is the so called "gravity loss".

Not for long.

On the other hand, accelerating horizontally through the atmosphere produces its own losses in the form of drag. So any rational launch design will seek to find the optimum path between the two launch strategies.

Every analysis ever done on the subject indicates that the optimal
path is up out of the atmosphere with a rocket, and then a gravity
turn, again with a rocket.

Define "optimal".

Sylvia.
.

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