Air-breathing hypersonic engines

On Friday, May 23, 2003, at 08:47 PM, Ian Woollard wrote:

>> Most rockets have only a few
>> percent payload because they have to lift all the fuel, and all the
>> fuel to lift that fuel, and so on.
>>
>>
> Yes about 1% payload is fairly typical. That doesn't directly push the
> costs up though; fuel is the cheap bit. It's the armies of people that
> are needed (or atleast used) to launch the vehicle that cost the money.
>

While the fuel is not particularly expensive, it needs large tanks to
hold it, pumping systems to move it, insulation on the external tank to
fall off and put holes in wings. The extra weight puts additional
structural loads during launch. It's explosive nature requires all
kinds of safety measures. Etc.

The materials in one asteroid (the largest ) are sufficient to make
orbital space colonies with ~500 times the surface area of the Earth in
usable real estate. See http://lifesci3.arc.nasa.gov/SpaceSettlement/
for details.

Al Globus
CSC at NASA Ames Research Center
http://www.nas.nasa.gov/~globus/home.html

Views expressed in this email are only my opinions and are not the
position of any organization I'm familiar with.