A kerosene-fueled X-33 as a single stage to orbit vehicle.

On 4/11/2010 12:42 PM, hcobb wrote:

Has *anyone* demonstrated that it is "better," student or otherwise?

"however, no end product is currently capable of orbit insertion using
this method."

Another problem is that if what it's suspended from is a unpowered
balloon, you aren't going to be able to predict exactly where it will go
in the high altitude winds.
One of the competitors for the GUSTO program (that later became OXCART
and developed the A-12/SR-71 Blackbird) was a Navy proposal for a
inflatable rubber ramjet (I'm not making this up) that would be carried
aloft by a huge balloon and then boosted by rockets to pick up speed
till the ramjet reached ignition velocity. Kelly Johnson found this
concept extremely amusing, especially when his BOTE calculations showed
that the balloon to carry it would be around a mile in diameter.

Pat