On Wed, 8 Oct 2003 03:37:48 GMT, (Henry Spencer)
wrote:

In article ,
Christopher wrote:
...Hydrogen is a lousy fuel; people are mesmerized by its high
Isp, and forget the heavy tanks and plumbing and the poor engine T/W.
What we care about is delta-V, not Isp, and the former is often actually
easier to get with fuels like kerosene.

Could the shuttle go up just as well using paraffin/kero and lox the
same as with it's current hydrogen fuel?

The SRBs might have to get somewhat larger, because the gross liftoff mass
of the orbiter plus ET would be higher. On the other hand, the ET itself
would get smaller and lighter (heavier when filled, but lighter when
empty) -- it's currently mostly LH2 tank.

Intersting. However would the launch cost's be the same or lower for
a kero-lox fueled shuttle?

Even setting that aside, note that the SSME is an incremental refinement
of Pratt&Whitney's 1960s RL20/XLR129 high-pressure-engine work. Nothing
very new there.

Didn't know that.

P&W was intensely ****ed off about it too -- from their viewpoint, NASA
led them on and had them do all the pioneering development of a somewhat
difficult technology, and then when it came time for a big production
contract, handed it to their arch-competitor and told them to get lost.

That's nasty, I don't like that, not very nice of NASA, P&W didn't
deserve it, as they to have to make a living. However, I [and maybe
lots of other people] was under the impression that the SSME was
cutting edge in rockets, ah well, I suppose that title is still held
by that Russian engine they developed for their moon rocket.

The improvements to be had are (with possible minor exceptions) not in new
fuels, but in better engines -- higher expansion ratios with altitude
compensation, lighter weight, longer operating life, lower costs.

So, what your saying is rocket engines could be developed like the
internal combustion engine has been, in that the car engine of 1963 is
a totally primative engine compaired to the 2003 car engine as we have
seen 40 years of development take place?

Right general idea, except that I would compare today's rocket engines to
the car engines of 1903, or maybe 1893, not 1963.

It seems we haven't advanced that far since Dr Goddard's first liquid
fueled launch in 1926, just increased the size of the engines or 77
years of more or less stationary progress.




Christopher
+++++++++++++++++++++++++
"Kites rise highest against
the wind - not with it."
Winston Churchill