> Spike Jones wrote:
> >
> > So now assume yourself a rocket designer. You are
> > given all the same constraints as the rocket designers
> > had in 65, with the exception that you need not return
> > payloads...Now what does your craft look like? spike
>
> Michael Lorrey wrote: Dyna-Soar, Hermes, HL-20, etc.
Heres where Im going with this. Using modern technology,
if you had to design a craft with all the same constraints they
had back in 1965, *you would end up with something that
looks a lot like the space shuttle*. Beats me how the heck
else you would return big payloads other than a big glider
with rocket engines.
If you had to return just the really expensive bits {motors
and meat}then you might do better, but consider this: since
a good engineer designs around standard parts, the shuttle
designers used the main engines already developed for the
Saturn V first stage. The SatV had 5, the shuttle has 3, but
they were already developed, so they used em.
By the same reasoning, if we were to develop a new
heavy lift reusable, we would likely do the math and recognize
that we have an external tank, already developed and being
mass produced, economies of scale, so we can buy these things
cheeeeapy cheap {as space hardware goes} 33 million bucks
each. Furthermore, when you actually do the math, the
strap on solids make sense too, for all the same reasons:
they are off-the-shelf parts now. Good chance it would
be cheaper to go ahead and throw away an external
tank than pay the price to have a totally reusable vehicle.
These observations lead me to these conclusions: that
a new heavy lift vehicle in the near future {next 20-30 yrs}
will look a lot like the shuttle, with external tank and
solids, and consequently the cost to orbit will not get
dramatically cheaper in that time frame, which means
the most promising route for space engineering is to
make the payloads dramatically more capable, as in
nanotech. spike
This archive was generated by hypermail 2b30 : Mon May 28 2001 - 09:59:41 MDT