Maximum Rate Shuttle Launches

On Wed, 13 Jun 2007 19:16:42 +0000 (UTC), in a place far, far away,
Rick Jones made the phosphor on my monitor glow
in such a way as to indicate that:

Also, why bother to automate it on a vehicle that will always be
manned? It's kind of like expecting a fighter aircraft to be able
to do mid-air refueling while the autopilot is on and the pilot is
sleeping.

I wonder if perhaps fighter pilots might like to have that feature

It wouldn't surprise me at all to learn that someone is working on
something like that for UCAV's...at which point it is a small matter
of porting right?-)

It's actually a lot easier to do it with a space vehicle than a
refueling aircraft, since the only force operating is gravity, which
is much more predictable than aerodynamics and wind gusts. While the
absolute speeds (relative to earth) are much higher in space, the
relative speeds are equivalent, and for space can be made arbitrarily
low (depending on the duty cycle and thrust level of the RCS).

On Jun 13, 2:16 pm, Rick Jones wrote:

It wouldn't surprise me at all to learn that someone is working on
something like that for UCAV's...at which point it is a small matter
of porting right?-)

http://www.wpafb.af.mil/news/story.asp?id=123033781

"Greg D. Moore \(Strider\)" wrote:

"Derek Lyons" wrote in message
...
"Greg D. Moore \(Strider\)" wrote:

After a year or so though, you start to hit into things like scheduled
maintenance (OMDP,)

That's not a problem for a sustained rate - because it's merely a
scheduling issue. It sounds like your write up was more based on 'how
long could a surge be maintained and how high would the surge rate
be'.

Partly yes. I didn't get to deep into how long a surge you could really
maintain etc.

That's what I thought.

Pondering, I wonder if the VAB isn't the limit though rather than the
MLP's - aren't only two bays (currently) outfitted for stacking?

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

Ian Parker wrote:

:
:What I am talking about specifically are aerodynamic simulation. You
:can put a shape in and know more or less exacly how it will behave.
:The A380 was designed in this way and all the results were within 2%
f nominal. When the Shuttle was built everyone who did not have what
:were then supercomputers simply stuck their fingers into the air.
:

Hint: You still build scale models and stick them in wind tunnels to
validate your simulation.

:
:A similar situation holds with regard to engine technology. One can
:fairly easilt find out what the stresses in the engine will be and see
:if the figures add up.
:

And, again, you still build the engine and fire it in a test stand.

Hint: What the design tools do is let you cut margins narrower.

:
:Yes enginers design spacecraft. What I am saying is that one you have
:a design you can get a pretty good idea of how it is going to work. Of
:course if the design is secret .....
:

You always could. And yet we still find surprises...

:In one thread the idea of having competitions was raised. This is a
:very sound principle. We said maintain a car in telepresence with a
:2.5 sec delay. With 3GHz and 1 GB RAM being pretty universal on new
:reasonably high end PCs we are at the point where we can give some
retty heavy duty software to competitors and let them attempt to do
:some designing. If people have their pet theories we could prove or
:disprove them relatively simply.
:
:Also please remember that the basic PC is far more powerful than the
:"supercomputers" that helped design the Shuttle. 1GB 3GHz what
:computer got anywhere near those specifications?
:
:One other aspect of competition. ProEngineer has a JLink interface. If
:NASA managed to sort out licenses this could be given to bright high
:school kids and undergraduates. A lunar robot fabricator could be
:designed and tested without bending metal.
:

Hogwash. Computers are no substitute for skilled, bright, and
well-trained engineers. You're not going to replace them with high
school kids, no matter how smart you high school kids think you are.


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn

Len wrote:

NaK would be solid on a cool day, but otherwise
liquid and more practical.

And by going to higher eutectics including other
alkali metals, you can get combinations that remain
liquid below the freezing point of mercury, IIRC.

Paul

"Fred J. McCall" wrote in message
...
Ian Parker wrote:
:One other aspect of competition. ProEngineer has a JLink interface. If
:NASA managed to sort out licenses this could be given to bright high
:school kids and undergraduates. A lunar robot fabricator could be
:designed and tested without bending metal.

ProEngineer? :-P Pure CAD models are devoid of engineering analysis. CAD
models are just pretty pictures in 3D unless you export the geometry to some
sort of analysis package.

Hogwash. Computers are no substitute for skilled, bright, and
well-trained engineers. You're not going to replace them with high
school kids, no matter how smart you high school kids think you are.

I'd even go further and say that you can't get your typical CAD user to do
your (complete) computer analysis/simulation, even if they have an
engineering degree.

Since I write this sort of analysis software (finite element analysis
pre/post processor) I can say that in general today's tools are very good
for analyses in one domain (i.e. structural, thermal, vibrational,
kinematics, or whatever). But most *hard* problems in the real world aren't
strictly one of these. They're almost always a combination of two or more
simulations, which is harder. Aerospace engineers are faced with problems
that span many domains simultaneously.

Also, the biggest problem I see is that even if the analysis you're going to
do is in one simple domain, like a structural analysis, the biggest problem
is determining what loads and boundary conditions you're going to use.
These are often your biggest unknowns when it comes to program input because
they depend on other analyses. If your results are bad, your inputs are
likely bad. Garbage in, garbage out applies to computer programs today as
much as it did to slide rules in the past.

You can't eliminate physical testing just because you have faith in your
computer programs or slide rules. Faith doesn't belong in engineering.
Test correlation does.

Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)

On Fri, 15 Jun 2007 14:10:44 -0400, in a place far, far away, "Jeff
Findley" made the phosphor on my monitor
glow in such a way as to indicate that:

But most *hard* problems in the real world aren't
strictly one of these. They're almost always a combination of two or more
simulations, which is harder. Aerospace engineers are faced with problems
that span many domains simultaneously.

Also, the biggest problem I see is that even if the analysis you're going to
do is in one simple domain, like a structural analysis, the biggest problem
is determining what loads and boundary conditions you're going to use.
These are often your biggest unknowns when it comes to program input because
they depend on other analyses. If your results are bad, your inputs are
likely bad. Garbage in, garbage out applies to computer programs today as
much as it did to slide rules in the past.

You can't eliminate physical testing just because you have faith in your
computer programs or slide rules. Faith doesn't belong in engineering.
Test correlation does.

Remember that you're talking to an idiot savant who thinks that we're
on the verge of being able to do everything with robots.

"Derek Lyons" wrote in message
...
"Greg D. Moore \(Strider\)" wrote:

"Derek Lyons" wrote in message
...
"Greg D. Moore \(Strider\)" wrote:

After a year or so though, you start to hit into things like scheduled
maintenance (OMDP,)

That's not a problem for a sustained rate - because it's merely a
scheduling issue. It sounds like your write up was more based on 'how
long could a surge be maintained and how high would the surge rate
be'.

Partly yes. I didn't get to deep into how long a surge you could really
maintain etc.

That's what I thought.

Pondering, I wonder if the VAB isn't the limit though rather than the
MLP's - aren't only two bays (currently) outfitted for stacking?



I'd have to check my numbers, but as I recall no.

The time spent stacking was about the same as on the pad.

And now that VAB bay #2 can support a stack (the "hurricane shelter") you
can stack and move to the other side and wait for a pad to be clear. Or
even stack some SRBs and a tank and move around and wait for a shuttle to be
ready.


D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

--
Greg Moore
SQL Server DBA Consulting Remote and Onsite available!
Email: sql (at) greenms.com http://www.greenms.com/sqlserver.html

In article ,
Fred J. McCall wrote:
:...When the Shuttle was built everyone who did not have what
:were then supercomputers simply stuck their fingers into the air.

Hint: You still build scale models and stick them in wind tunnels to
validate your simulation.

And if you don't, you tend to end up with egg on your face, like the
designers of the Pegasus XL... who put a lot of trust in their CFD models,
only to find out the hard way that they should have done more wind-tunnel
testing.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

On Jun 15, 5:44 pm, "Ed Ruf (REPLY to E-MAIL IN SIG!)"
wrote:
[...]
NASA's best most recent attempt at doing this might have been the Hyper-X
Mach 7 and 10 flights. In both cases the overall drag of the vehicle was a
priori under predicted. In both cases the full vehicle/engine flight state
was computed after the fact quite well, based upon trajectory information.
However, these computations after the fact far and above surpassed anything
which was possible a priori in the development of both the aerodynamic and
propulsion force/moment databases given the resources available.

Hey, actual data Is Not Allowed in this forum!

/dps