Space Forum / Space Flight / October 2005

Hmm, the idea looks far-fetched, but the Economist magazine has
bothered to give it some coverage:

http://www.economist.com/science/displayStory.cfm?story_id=4455446

The fellow claims it may be possible to create a convection-fed vortex
within a 100-meter high and 200-meter wide "chimney", which could
extend kilometers above it into the sky, like a tornado.

The application as described in the article is for a power-generating
plant. But could this idea somehow be used for launching payloads into
space?

Leaving aside the technical problems of generating and controlling such
a gigantic artificial cyclone several kilometers in height -- just for
the sake of discussion, could such a cyclone generate the lift to
accelerate and hurl an unmanned payload high in the sky and perhaps a
substantial part of the way to LEO?

Suppose our launch vehicle has a hydrogen propulsion system similar to
the space shuttle's main booster, but scaled down. The rocket exhaust
would consist of high temperature steam. Could this be used to feed and
sustain the vortex at higher altitudes, perhaps with an exceptionally
wide bell?

On a vaguely related note, here is a picture of what looks to be a very
tightly bound vortex (9 feet in height??) produced by burning fuel:

http://www.reelefx.com/Tornado/firetube.htm

Could such a vortex be produced from the exhaust plume of a rocket, and
would it offer any propulsive benefit?
I assume that a vortex can only be maintained due to the pressure of a
surrounding medium, and yet perhaps that groundstation-produced
artificial tornado could offer substantially higher atmospheric
pressure upto a distance of several kilometers from the ground.

Consider that an acceleration ramp several kilometres high is nothing
to sneeze at, in comparison to what some of the proposed large
electromagnetic railguns could give. Not as long as the Space Elevator
of course, but at least a column of air can't snap as easily.