[ExI] skylon/SABRE

[Keith Henson]

On Mon, Jul 16, 2012 at 5:00 AM,  "spike" <spike66 at att.net>> wrote:

> Keith's vision may be a step closer:
>
> .Reaction Engines has announced that is has successfully tested the key
> pre-cooler component of its revolutionary SABRE engine crucial to the
> development of its SKYLON spaceplane
> <http://www.gizmag.com/skylon-spaceplane/19033/> . The company claims that
> craft equipped with SABRE engines will be able to fly to any destination on
> Earth in under 4 hours, or travel directly into space...

My "vision" such as it is stems from the observation that if we
already had a power sat and equipped it with propulsion lasers,
further power sats would be a very expensive way to make electric
power.  In fact, the power would be so cheap the current oil companies
could use it to make carbon neutral synthetic transportation fuels for
~$1 per gallon.

The profits from doing this are so high that it seems to be worth
putting up a first power sat dedicated to propulsion with relatively
conventional means, such as Falcon Heavy or Skylon.

Reaction Engines isn't particularly enthusiastic about taking out the
oxygen tank and adding hydrogen heaters for a Gen II laser powered
Skylon.  However, if the organization doing this wants to buy 16 of
the original design for building up the seed power sat and propulsion
lasers, they will probably go along with a Gen II design.  :-)  The
mass fraction that gets to GEO for the Gen II is 6 times that of the
"conventional" Skylon.

Two weeks ago I talked about this project at an Advanced Concepts
conference at ESTEC in the Netherlands.  (Two days of conference and
two days of flying, oh my.)  I discussed the topic with a packed room
for over an hour.  There was a bit of sticker shock since my initial
estimate was 35 times ESA's yearly budget, but there was general
agreement that I have the physics and economics at least plausible.

I have a 17 page draft article going off to the JBIS this Friday.  I
can't make it pubic, but if some of you want to read it and comment, I
can send you a copy for review.  Don't ask unless you think you can
get comments back to me by Thursday.  Dr. Phil Chapman read an earlier
version.  He wrote three pages of comment/objections that I mostly
incorporated.

Keith