garfangle wrote:

Instead of hauling their own fuel for propellent, which adds to its
weight, why not have manned craft launched from massive high-altitude
cannons? Why not further what the late-Gerald Bull envisioned (see
world.std.com/~jlr/doom/bull.htm) to build a supergun that could
launch projectiles large enough to be duplicated as manned capsules?
That way there would be little or no need for external boosters to be
hauled alongside the manned vehicle, greatly reducing the per pound
flight costs.

The gun could be large enough to shoot the craft into near-low earth
orbit and then small internal rockets could be used to get the craft
further into space. The craft could be sized such that it replicated
the apollo.

I imagine the dimensions would be at least 500 meters long, 30 meters
in diameter, and require an explosive shot of several tons of tnt.

Ciao.


All this is fine, for acceleration-insensitive payloads....

Which rules out humans, but might not be a bad idea for things like
radioactive wastes, or even plain water, which would have multiple uses,
once in LEO.

But even if you had an intended-to-be-manned-later (if I'm
understanding you correctly) spacecraft that could itself tolerate this
mode of launch, you still have to get its crew up to LEO to meet it,
some other way. And anything intended to go deeper into space, Jules
Verne not withstanding, is likely going to be too big to be orbited in
this manner. Thus my above point for firing water, and using it as is
for life-support purposes, or electrolyzing it with solar power into H2
and O2, to fuel something else.