should space shuttle be cancelled?

"Cardman" wrote in message
...
On Mon, 1 Aug 2005 19:12:30 +0200, "Henk Boonsma"
wrote:

CardMan did you follow the news about the foam shedding AT ALL?

I watched it live as it happened. I have also been keeping up with
what the stupid scare story seeking tabloid media have been saying.

The foam
that broke off could have easily punctured the wing just like it had with
Columbia if it had come off just a couple seconds sooner.

That would be a snowballs chance in hell situation.

To begin with then the foam that got Columbia was certainly both quite
larger and most importantly it came off in the low Earth atmosphere,
when Columbia was ploughing though it a quite some speed.

The foam piece wasn't that much larger and could have damaged a wing panel
irrepairably had it come off with greater speed.


In the case of Discovery this foam only came off due to what appears
to be direct SRB separation. So it did not, and would not, have come
off when it could have posed a danger.

AFAIK this link hasn't been made nor has it been proven. It might well have
come off earlier, there's no telling at this time.


Indeed it seems like the case that Discovery traveled through this
lower atmosphere danger zone with no foam loss at all. That should be
a first for any Shuttle launch.

Certainly this foam loss is undesirable, but this tiny risk is not
reason to ground all their Shuttles for.

Since Discovery was well up into the high atmosphere at this point
then that it why this foam slowly drifted away. As I said before I am
sure that you could head butt that foam without knocking your brains
out. So had it hit Discovery, then it simply would have bounced off.

What is more is that since this foam came off due to the SRB
separation, then so did the passing SRB create a pressure void that
this foam was sucked into. And well away from Discovery.

So based upon the cause, and resulting affect of this foam loss, then
I would declare their previous foam problem completely fixed.

Luckily this time around we would have known about it

Yes, NASA does not do too well with foresight.

but it would at the very leas it would
have meant the loss of another Shuttle (repairing it in orbit would be
virtually impossible)

Oddly enough, NASA this very trip, is testing their new repair
procedures. Although I really cannot see the point of repairing the
chip marks on the tiles.

The repairs their doing are bull**** and you know it. They're trying to fix
small dents in tiles that don't need fixing just to satisfy the American
public and the politicians. There's no way that they can repair a carbon
panel on the wing, and they've said to publicly.

Pat Flannery wrote:

Question of the week: before the launch, someone asked the Shuttle's
crew what they would do if the Shuttle were damaged during ascent, but
they used their repair ability to fix it on-orbit- would they then trust
it for reentry?
The reply was "no"- they would stay at the ISS and await rescue.
I notice no further discussion on this particular option has occurred
since the the decision to do the repair EVA has been announced.

well, that was in reference to tile damage, not to the cladding in
between coming loose. Way different scale problem.



The other interesting question is: Since some pads between TPS tiles are
hanging half out of their channels...have any fallen _completly_ out,
and how will it affect reentry if they have?

during the press conference this morning they mentioned that the padding
is there to smooth out the airflow during ascent (while the ET is
creating different turbulence patterns and airflows and such), it's not
for thermal protection during descent. So it apparently won't make any
difference on the way downhill.

One devoutly hopes.


--
Terrell Miller


"Suddenly, after nearly 30 years of scorn, Prog is cool again".
-Entertainment Weekly

On Tue, 2 Aug 2005 22:15:29 +0200, "Henk Boonsma"
wrote:

"Cardman" wrote in message
To begin with then the foam that got Columbia was certainly both quite
larger and most importantly it came off in the low Earth atmosphere,
when Columbia was ploughing though it a quite some speed.

The foam piece wasn't that much larger

I would question that. I have closely examined both Columbia and
Discovery video, where there seems to be a noticeable size difference.

and could have damaged a wing panel
irrepairably had it come off with greater speed.

Greater speed depends on thicker atmosphere. Discovery seemed to pass
through that danger zone scratch free.

So already you have two reason why it does not match Columbia.

In the case of Discovery this foam only came off due to what appears
to be direct SRB separation. So it did not, and would not, have come
off when it could have posed a danger.

AFAIK this link hasn't been made nor has it been proven. It might well have
come off earlier, there's no telling at this time.

Certainly it is a best guess situation. However, you should look at
the bigger picture.

I would say that this glitch has about a 1 in 200 chance of becoming a
more serious problem. What is more is that if this came off due to the
SRBs, then it is not even a problem at all. I would give those odds
about 50/50.

So you could estimate that their next September launch could have
taken on a 1 in 400 risk of becoming a real problem. What is more is
that since they now know all about foam damage, then so could their
back-up plans be put into use.

And so the real odds of a crew suffering "foam death" comes in as
negligible.

My point simply is that how can they ground their Shuttles over a
negligible concern, when the Shuttle has far greater odds of killing a
crew through one of many other reasons?

What is more is that by fixing this undesired glitch during on-going
launches, then although their next mission would have taken on this
extra 1 in 400 risk, but it could well be all fixed by the time that
future launches come about.

And you can rest assured that this method would more than double the
launch rate over how they are currently doing it.

Oddly enough, NASA this very trip, is testing their new repair
procedures. Although I really cannot see the point of repairing the
chip marks on the tiles.

The repairs their doing are bull**** and you know it. They're trying to fix
small dents in tiles that don't need fixing just to satisfy the American
public and the politicians.

Sounds like rats playing to the tune of the piped piper.

Still, you can at least be assured that some people are not a dumb as
what NASA would like them to be. News of their plan to do an extra
spacewalk made me smile, simply by knowing how pointless it was.

NASA would be insane to do this every mission.

There's no way that they can repair a carbon
panel on the wing, and they've said to publicly.

Oddly enough I watched a video clip on NASA TV where they seemed to
indicate that they could do exactly that. Still, you are quite correct
that this seems like a job beyond their ability.

My thought about this problem has always been that they should simply
"plug up the hole". That should be a lot more feasible than with
trying to replace a fragile carbon wing panel.

Cardman.

"Pat Flannery" wrote in message
...
Which they will no doubt describe as a "triumph" given the PAO's normal
approach to things.

Everything, except loss of orbiter and crew, is a triumph to NASA PAO. It's
their job to put a positive spin on absolutely everything they can.

Jeff
--
Remove icky phrase from email address to get a valid address.

stork wrote:

I was all in favor of the CEV but I'm more inclined to push along on
the OSP approach. If, instead of the CEV, we were building a new class
of shuttle, what would some of the requirements be?

a) Capable of leaving LEO, comes to mind.


Why try to be all things to all people? Let an orbital transport be
that. Go on to the Moon in something else, (a'la 2001). The only way a
single vehicle could be justified is if it were already a VTVL, than
with orbital refueling, you may have something that could do quick and
dirty single ship flights.

Unless there's a useful atmosphere at the other end, or you have some
fantastic propulsion with enough energy to make it a non-issue, leave
your wings at LEO.


The shuttle we have now is huge and can theoretically stay in space
long enough to go to the moon and back.


And ISS can do so, long enough to get to Mars (well, with decent
propulsion)...which doesn't make it a Mars ship.


If we build a new one, have
it able to go farther into space? Couldn't we have a shuttle of
similar size but with more fuel in either the cargo bay


Then where does the cargo go?


or a previously
launched external tank to get this puppy to the moon? We could put the
lunar lander and lots of other stuff in the cargo bay. 10,000 lbs of
lunar ore ought to be enough for decent assays.


See my previous comments on dedicated space-only (rember the LEM?),
or Earth-launched VTVL.


b) Better thermal management

Obviously, the tiles have to go. But what to replace it with? A lunar
inbound shuttle would have to use a normal ablative heat shield because
it would be going that much faster, would it not?


And a one-piece ablative heat shield may be harder to replace for the
next flight, than tiles.


c) An onboard jet engine.

One pass at landing sucks.


That engine and fuel for same weighs something. You already want it
to be able to do to many things. Give up some of them for that powered
landing.


d) Horizontal landing, horizontal takeoff, horizontal processing. It
seems awefully complicated to pick up a 100 ton aircraft and put it on
its rear end, and then work on it at weird angle.


VTVL. And/or air-launched two-stage HTHL.


e) Easier turnaround stuff. It seems like every time they launch the
shuttle they practically have to take the whole thing apart and put it
together again.


Yes.


Finally

f) Instead of spending 3 billion dollars on a perfectly safe vehicle,
accept some losses at 1 billion a piece and pay the astronauts 20
million bucks a flight.

Do you want to build a reliable transportation infrastructure on that
logic?


--

You know what to remove, to reply....

Cardman wrote:

But the fact remains that the Shuttle is *fundamentally flawed* in many
ways, both in concept and design.

I do not believe that. The only real flaw I see in the Shuttle system
is in having no crew escape system. All the other problems with the
Shuttle are simply technology not meeting Shuttle requirements.


The biggest flaw is being a vehicle that even *needs* a crew escape
system.

We only do this in aircraft where some outside force may actively be
trying to destroy you. (fighters and bombers) Almost everything else is
sufficently robust that we don't consider it, we expect 'intact abort'
in virtually all cases.


--

You know what to remove, to reply....

On Wed, 03 Aug 2005 01:54:31 GMT, Joann Evans
wrote:

The biggest flaw is being a vehicle that even *needs* a crew escape
system.

True, but rocket launches are considerably more dangerous than
aviation. Ignoring this current fact would be unhelpful.

We only do this in aircraft where some outside force may actively be
trying to destroy you. (fighters and bombers) Almost everything else is
sufficently robust that we don't consider it, we expect 'intact abort'
in virtually all cases.

Maybe you have not noticed, but in the case of both Challenger and
Columbia, they were both destroyed by outside forces. So the very
environment that they are in is the thing that is trying to destroy
them.

Now had the Shuttle came with an escape system built in, then both of
these crews may have survived. I am thinking of a detachable cockpit
that forms into a crude craft.

Certainly the case of the CEV is a whole different safety concern,
where simply mounting this craft on top provides a huge advantage over
the Shuttle.

That rocket goes and does it's worst during flight, then with only a
little luck they should survive with only getting a little cooked. I
can only say that it would be helpful if the CEV could detach itself,
should the rocket go way off course. Like straight down.

Anyway, it would simply be wrong to ignore that launching and reentry
does carry a high level of risk. Ignoring it won't make it go away,
which is why they should certainly plan for what can go wrong.

Cardman.

Joann Evans wrote:
The biggest flaw is being a vehicle that even *needs* a crew escape
system.

We only do this in aircraft where some outside force may actively be
trying to destroy you. (fighters and bombers)

While combat losses are correctly the origin of interest
in ejection seats, they have saved far more pilots in peacetime
than in war, according to the statistics I have seen.

They are now installed on non-combat aircraft such as trainers.

Almost everything else is
sufficently robust that we don't consider it, we expect 'intact abort'
in virtually all cases.

Note that escape and hard abort systems are now
proliferating in light aircraft. See for example
the light aerobatics ejection seat the Russians
are selling here nowadays, and the great sales
and saves that BRS Parachutes are getting.
BRS has saved something like 179 people so far.

Aviation isn't as robust as you claim it is.



-george william herbert

Joann Evans wrote:


Unless there's a useful atmosphere at the other end, or you have some
fantastic propulsion with enough energy to make it a non-issue, leave
your wings at LEO.

Better still, leave the wings on the ground.

It's absurd to deliver over 100 tons into LEO, of which only 20 tons
max is cargo.

In article . com,
"Alex Terrell" wrote:

Better still, leave the wings on the ground.

It's absurd to deliver over 100 tons into LEO, of which only 20 tons
max is cargo.

No it's not.

That would be just fine if doing it bought you the ablity to land from
one mission, fill up the tank and kick the tyres, and take off on the
next mission a day or two later.

--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------