Air-breathing hypersonic engines

There's at least one proposed craft on the internet that combines a
rocket-assisted turbofan from takeoff to Mach 2, a ramjet up to Mach 8, then
a scramjet from there to about Mach 15. This guy has worked out a lot of
the engineering. However this is still the first stage, and the point of
this amazing aircraft (in his scheme) is to bring a second stage close to a
skyhook hanging down into the upper atmosphere, attached to a Space
Elevator-like satellite in geosynch.

see
http://www.affordablespaceflight.com/nasa1.html

I'm not aerospace engineer, but I'm impressed with the amount of work he's
done in thrust, weight, fuel mixes and powerplant design.

>A scramjet would also need a first stage to get it up to a sufficient
>speed at which the scramjet can 'start'. Ramjets and scramjets can't
>just take off from a standing start on a runway. If you disagree, then
>please provide a reference URL; thanks.
>
>Thus, you'd need
>1.) A first stage, to accelerate the package from a standing start to some
>supersonic speed at which the scramjet could start.
>2.) A second, scramjet stage, to accelerate the package from some
>hopefully low starting Mach number to a high Mach number within the
>atmosphere.
>3.) A third rocket stage for the final push to orbit plus circularization.
>
>There are already two-stage-to-orbit rockets such as Delta IV. Do you
>think that a three-stage-to-orbit system with scramjet as the second stage
>would be preferable to a two-stage-to-orbit vehicle?
>
>Ron
>******
>
>Al Globus
>05/29/03 11:55 AM
>Please respond to spacesettlers
>
> To: spacesettlers@yahoogroups.com
> cc:
> Subject: Re: [spacesettlers] Re: Air-breathing hypersonic
>engines
>
>On Tuesday, May 27, 2003, at 03:45 PM, Ian Woollard wrote:
>
> > Scramjets seem to be mostly interesting to the military- they want to
> > go
> > places really quickly, outrace all the missiles etc. etc. But getting
> > to
> > orbit? It might make a good first stage, but you're still going to need
> > rockets either in the first stage (in which case the scramjet has added
> > quite a bit to your first stage's orbital weight), or as a second (in
> > which case you've spent lots of money to create a not very special
> > first
> > stage).
> >
>Obviously a scramjet by itself can't get you to orbit, at the very
>minimum you need a rocket for the circularization burn. However, by
>radically reducing the wet weight of a first stage they could make a
>major contribution. For example, if my a calculation I did a couple
>years ago is correct, it's interesting to note that on the shuttle the
>solids are there mostly to lift themselves and the oxygen.
>
>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.
>

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