Going to the moon...again?

On Mon, 16 Feb 2004 08:37:47 +1100, Sylvia Else
wrote:

Charles Buckley wrote:

NASA has a good rundown of the whole decision process at:

http://history.nasa.gov/SP-4221/sp4221.htm


Thanks for the link, Charles.

I've taken a look at that.

There are dangers in comparing the real shuttle hardware that's in place
with hypothetical other approaches. Still, I found the idea of a
titanium stubby winged orbiter quite compelling.

The objections to this seem to have been:

a) Not so much knowledge in the industry of titanium manufacture. Well,
how many of these things did they intend to build anyway?

My understanding was that the USAF wasn't too keen on NASA going with
a Titanium shuttle due to supply concerns. This was at a time when the
USAF was planning thousands of F-15's and hundreds of B-1's which were
expected to put large demands on the nations production of Titanium.
Sharing it with a Shuttle program was a concern and the situation that
NASA was in to get the shuttle funded meant that they were over a
barrel when it came to USAF demands. (The Shuttle needed the USAF, but
the USAF didn't need the Shuttle)

b) Cross range limits. Could have been lived with.

c) Transition from deep stall descent into normal flight. Aviation has
rightly been concerned with deep stalls, and it has caused a few
crashes, but these were aircraft that were never intended to operate in
that region. There was also concern that you have a craft that is
presumably travelling in a fairly steep path at the point where it has
to start flying, so it will accelerate, downward, quite quickly. But
this is just physics, and should be manageable.

On the plus side, you have a much smaller area to protect from heating.
More energy is dumped into the shock wave, and less has to be lost from
heating. Lower structural weight. And the aerodynamics are of a craft
operating in the subsonic region - not even transsonic. You don't have
to build a hypersonic glider with acceptable subsonic characteristics.

Will this be revisited now? Or will the next shuttle also be a delta wing?

I doubt there will be a next shuttle for a while. Although wings are
sexy they are pretty much dead weight for %95 of the flight. The
Shuttle system launches as much payload into orbit as the Saturn V,
its just that most of it is the shuttle itself, the wings of which are
only good for the last 10 minutes of flight.


Kelly McDonald

Sylvia.