The wet Shuttle ET

BlagooBlanaa wrote:
water is heavy, frozen or not
accelerative loads make it more so
greatly increasing the probability of failure
when shuttle launches

they gotta scrub the mission and pull those
fricken tanks apart and put them together right.

One of the nice things about reengineering ETs
for potential human habitation is that they get
RE-ENGINEERED - properly this time.


Oh please. The whole ET as space station module died years ago with the
development of the Transhab inflatable module technology.
-Mike

Pat Flannery wrote in news:12a0qn28o9vja61
@corp.supernews.com:

Brian Thorn wrote:

You've eliminated the big foam shedding sources from both STS-107 and
STS-114.

That's an assumption;

No, it's not. It is physically impossible for bipod ramp foam or PAL ramp
foam to come loose in future flights, as happened on STS-107 and 114, since
both ramps have since been removed entirely.

if we don't know what exactly is causing the
shedding we can't be sure we aren't going to get more and in unexpected
sizes.

While true, that's independent of the point Brian was making.

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JRF

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"Matt" wrote in
ups.com:

For all the technology and engineering brainpower being thrown at the
foam problem, it bothers me that NASA is essentially flying four
versions of the tank on succeeding flights: the "old" ET carried on
the fatal Columbia flight (STS-107), the modified one used on last
year's "return to flight" Discovery mission that resulted in more
(although not deadly) foam events (STS-114), the one being used on
this flight (STS-121), and the one slated for the shuttle Atlantis on
the next flight (STS-116), which will have further modifications
already decided on. It's not clear to this non-engineer that the
accumulation of data from flying four designs isn't so complex it
could actually conceal a problem rather than spotlighting it.

It would be a lot easier to conceal a problem by waiting and making all
four modifications at once. That would make it impossible to isolate the
effects of each mod.


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In article ,
Pat Flannery wrote:
What they really needed, particularly given the Cape's wet climate, was
a building that could entirely enclose the Shuttle to just an hour or so
before launch, like Vandenberg was going to have for its Shuttle launch
facility.

Well, the Cape pretty nearly has one -- the VAB. There's no fundamental
reason why the shuttle can't be *ready to fly* at rollout. As soon as
it's hard down on its mounts at the pad, you start filling the ET as the
crawler beats a hasty retreat, and towards the end of fueling, the crew
boards. You time it so the tanks are full five minutes before the launch
window opens. (Okay, maybe half an hour if you're feeling cautious. :-))

That's how the VAB was conceived to operate, with *all* preparations done
indoors in a protected environment. KSC has never managed to do it, but
the Ariane 5 launch facility at Kourou demonstrates that it is possible.

I expect you'd need a considerable overhaul of procedures, and probably
some equipment changes, to do that for the shuttle. And it's a bit late
to do that now. But there's nothing fundamentally hard about it.

In that way you could pick a nice sunny day to roll the Shuttle out to
the pad from the VAB, and keep the rain off of it once it had arrived.

Barring further facilities changes, you want to do the rollout when NASA
does it -- in the predawn hours -- because the orbiter has no lightning
protection between the VAB and the pad(*), and that's the time of day when
surprise thunderstorms are least likely. A nice sunny day is actually
about the worst time; that coast gets *lots* of short-notice thunderstorms
on nice sunny days.

(* A side effect of moving the umbilical towers from the mobile platforms
to the fixed pads. The Saturn V could and did roll out in bad weather; on
one occasion the crawler had to stop for a while, en route to the pad,
because it was raining so hard that the drivers couldn't see ahead. )
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In article ,
Pat Flannery wrote:
Although real-world testing is always the best way to go, real-world
testing with a fully crewed flight seems over-the-top in regards to
safety concerns...

The question is not whether flying with a full crew involves danger, but
whether the danger can be substantially reduced by a modest further delay.
There does come a time when real-world testing is the right way to resolve
uncertainties, even though it does come with a certain element of risk.

Yes, losing another shuttle would be a serious political problem, but
being grounded for so long is also becoming a political problem.
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James Nowotarski wrote:

The answer is obvious! Immediately before fueling we fill the tank
with hot coffee!
Or tea. Or both, since we have two tanks. Then when we see the steam
no longer coming from the insulation, we drink the coffee or tea (or
both) and load the propellants. If we have the crew drink it, we also
gain productivity, since they won't be sleeping for the next couple of
weeks.

Thank you, no cheers required, just throw money...


I propose we put a layer of solid rocket fuel over the foam and ignite
it just before launch; now the exterior of the tank will be very hot,
the interior very cold, and the foam at around room temperature.
As the shuttle ascends, this fuel (which will be mixed oxygen-poor) will
cause a fuel rich exhaust to flow into the area behind the ET causing a
external combustion plug nozzle effect that will add thrust and reduce
boattail drag, thereby more than making up for the weight of the fuel
coating.
Now mind you having an inferno blazing just below the orbiter's belly
might be deleterious to it, so it must be hung at the end of a long
carbon fiber tow cable/propellant feed line (say 2000' or so) beneath
the base of the ET.
Any foam that does shed will certainly be burned up by the SRB exhaust
long before it reaches the orbiter.
In this manner we also give it an abort capacity as it must merely sever
the cable in case something goes wrong with the ET or SRBs and the
shuttle can then glide back as the rest of the stack heads for parts
unknown...say a Colombian coffee plantation, or better yet a cocaine
field. In this way any time we have a failed Shuttle launch there will
be trouble brewing for the drug industry, so all would not have been for
naught.
No cheers needed, just throw cream.

Pat

Jorge R. Frank wrote:

The as-is config did indeed do better than the
redesigns, and that was the basis for the program decision to fly with the
ice/frost ramps as-is.



Which the Chief Engineer and Safety Officer think has a problem.

Pat

Jorge R. Frank wrote:



It was thought that the original painting of the tank that was done on
the first few flights added both to the tank's waterproofing and foam
shedding resistance, but that was dropped to save weight and cost.



And also because there was no evidence that it helped. STS-1 and 2 had just
as many tiles replaced due to foam impacts as the flights with unpainted
tanks.



But in that case the tank manufacturer hadn't had much experience yet
building or insulating the tanks; you'd expect a learning curve,
especially when it came to foam application techniques, as the years
went by.

Pat

Pat Flannery wrote in
:

Jorge R. Frank wrote:

The as-is config did indeed do better than the
redesigns, and that was the basis for the program decision to fly with
the ice/frost ramps as-is.

Which the Chief Engineer and Safety Officer think has a problem.

Apparently not bad enough of a problem for either one to formally object to
the launch. Neither would be reluctant to do that if they really did have a
problem with it; O'Connor in particular *has* resigned a NASA position in
protest previously in his career, when he thought crew safety was being
jeopardized.

Anyway, it doesn't change the need to correct the (apparently widespread)
misperception that NASA is flying an ice/frost ramp config that did *worse*
in wind tunnel tests.

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JRF

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"Henry Spencer" wrote in message
...
In article ,

Well, the Cape pretty nearly has one -- the VAB. There's no fundamental
reason why the shuttle can't be *ready to fly* at rollout. As soon as
it's hard down on its mounts at the pad, you start filling the ET as the
crawler beats a hasty retreat, and towards the end of fueling, the crew
boards. You time it so the tanks are full five minutes before the launch
window opens. (Okay, maybe half an hour if you're feeling cautious. :-))

That's how the VAB was conceived to operate, with *all* preparations done
indoors in a protected environment. KSC has never managed to do it, but
the Ariane 5 launch facility at Kourou demonstrates that it is possible.

I expect you'd need a considerable overhaul of procedures, and probably
some equipment changes, to do that for the shuttle. And it's a bit late
to do that now. But there's nothing fundamentally hard about it.

One major change they'd need now is to do all payload processing in the VAB.





(* A side effect of moving the umbilical towers from the mobile platforms
to the fixed pads. The Saturn V could and did roll out in bad weather; on
one occasion the crawler had to stop for a while, en route to the pad,
because it was raining so hard that the drivers couldn't see ahead. )

Considering how slowly the crawler moves I've got to admit I'm a tad
skeptical of this one (at least that reason).

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