kirjoitti:
Mitch wrote:

Should this not allow for much greater payloads to be
carried since less fuel is needed to get up to 30,000 ft?


Not *much* greater payloads.

There is an improvement. The spacecraft can be smaller, or deliver a
slightly larger payload, or get into orbit in a single bound.

But 30,000ft and, say, 600mph isn't much of a boost. It's a long, long,
long way from orbit. The difficulty of getting to orbit is better
described by "17500 miles per hour" than any figure of altitude.


Why is that speed needed?

Only thing I can think is, that since earths gravity effects the craft
whole time, the longer it takes, the more gravity will "drag back" the
craft?


But also gravity gets smaller when you get more away from the earth?
How high does one have to go to have only half of gravity?



What if someone built a 30,000 ft high tube, similar to magnetic trains
- electrical magnets around it. Then you could just put metallic
cargo inside - without any engine or fuel, and shoot it up. The tube
would have to be high enough that there is no air where the cargo comes
out, and maybe part of the tube would have to be a vacuum.

Propably not something to do today, but still lot shorter than the
"space-lift", and it would give near 100 % payload.

(you could mix magnetic cargo with-non magnetic)
And maybe design some kind of shell that can used as "package" to shoot
cargo up, and then used as walls for space station or building in other
planet.