The ISS leak

Though apparently not actually a serious problem, the way they have to find
leaks seems long and time consuming, something that may not be a possibility
to have if a serious leak occurred.

Is there no technology that could be used to find leaks, or at least pin
them down more accurately when they occur?

I have never heard of such a leak on a Shuttle, though I have noted comments
about chipped windows in the past.

My gut feeling is that that odd sound that was heard may have something to
do with this problem.

How are wires etc, that need to get to aerials, passed through the body of a
craft to remain air tight? It occurred to me that a loose antenna that might
look fixed, could easily tug on a cable and eventually break a seal.

Brian


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Brian Gaff....
graphics are great, but the blind can't hear them
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Though apparently not actually a serious problem, the way they have to find
leaks seems long and time consuming, something that may not be a possibility
to have if a serious leak occurre

It would make more noise and be sucking stuff towards the leak. since it was
small it was hard to find.

"Brian Gaff" wrote in
:

Though apparently not actually a serious problem, the way they have to
find leaks seems long and time consuming, something that may not be a
possibility to have if a serious leak occurred.

This leak was hard to find precisely *because* it was so small.

My gut feeling is that that odd sound that was heard may have
something to do with this problem.

Not likely; the sound was heard in the Zvezda service module at the aft end
of the station, while the leak was found in a flex hose in the US lab, near
the forward end.

--
JRF

Reply-to address spam-proofed - to reply by E-mail,
check "Organization" (I am not assimilated) and
think one step ahead of IBM.

Oh, you are obviously ahead of me then. I had not heard they had found it. I
look forward to reading about it on the news group.

Brian

--
Brian Gaff....
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________
__________________________________


"Jorge R. Frank" wrote in message
...
| "Brian Gaff" wrote in
| :
|
| Though apparently not actually a serious problem, the way they have to
| find leaks seems long and time consuming, something that may not be a
| possibility to have if a serious leak occurred.
|
| This leak was hard to find precisely *because* it was so small.
|
| My gut feeling is that that odd sound that was heard may have
| something to do with this problem.
|
| Not likely; the sound was heard in the Zvezda service module at the aft
end
| of the station, while the leak was found in a flex hose in the US lab,
near
| the forward end.
|
| --
| JRF
|
| Reply-to address spam-proofed - to reply by E-mail,
| check "Organization" (I am not assimilated) and
| think one step ahead of IBM.


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Jorge R. Frank wrote:

"Brian Gaff" wrote in
:

Though apparently not actually a serious problem, the way they have to
find leaks seems long and time consuming, something that may not be a
possibility to have if a serious leak occurred.

This leak was hard to find precisely *because* it was so small.

My gut feeling is that that odd sound that was heard may have
something to do with this problem.

Not likely; the sound was heard in the Zvezda service module at the aft
end of the station, while the leak was found in a flex hose in the US lab,
near the forward end.


I read that the maximum rate was as much as 5 lbs per day. 5 lbs / 0.07
lbs/ft3 which equals 71 ft3 per day or 500 gallons of air. That a lot of
volume passing through the leak.

It seems that is was so hard to find because of all the background noise in
the module masked the sound of the air going supersonic. Also, the leak
wasn't a constant, and was dependant on the flex in the hose. So, it was
probably changing rate every time an astronaut went to look out the window
and bumped the hose, which caused the leak in the first place.

Craig Fink

Craig Fink wrote in
k.net:

Jorge R. Frank wrote:

"Brian Gaff" wrote in
:

Though apparently not actually a serious problem, the way they have
to find leaks seems long and time consuming, something that may not
be a possibility to have if a serious leak occurred.

This leak was hard to find precisely *because* it was so small.

I read that the maximum rate was as much as 5 lbs per day. 5 lbs /
0.07 lbs/ft3 which equals 71 ft3 per day or 500 gallons of air. That a
lot of volume passing through the leak.

It's still orders of magnitude less than the Progress-Mir leak in 1997. The
ISS air supply was sufficient to feed this leak for months, if necessary.

--
JRF

Reply-to address spam-proofed - to reply by E-mail,
check "Organization" (I am not assimilated) and
think one step ahead of IBM.

Jorge R. Frank wrote:


Not likely; the sound was heard in the Zvezda service module at the aft
end of the station, while the leak was found in a flex hose in the US lab,
near the forward end.



How far away from the US lab is the Zvezda module?

If the noise was heard in the Zvezda module maybe it was the sound of the
hypersonic plum impingement on some external part of the Zvezda module. I
wonder about the bang they heard, if was the initial failure like the
popping of a bubble. Didn't they also hear some other sounds like sheet
metal flexing. Maybe that was something flapping in the hypersonic breeze
outside.

Craig Fink

Jorge R. Frank wrote:

Craig Fink wrote in
k.net:

Jorge R. Frank wrote:

"Brian Gaff" wrote in
:

Though apparently not actually a serious problem, the way they have
to find leaks seems long and time consuming, something that may not
be a possibility to have if a serious leak occurred.

This leak was hard to find precisely *because* it was so small.

I read that the maximum rate was as much as 5 lbs per day. 5 lbs /
0.07 lbs/ft3 which equals 71 ft3 per day or 500 gallons of air. That a
lot of volume passing through the leak.

It's still orders of magnitude less than the Progress-Mir leak in 1997.
The ISS air supply was sufficient to feed this leak for months, if
necessary.



Yeah, I agree.

That leak was probably so big they could have found by watching all the
stuff floating towards it. That is, if they weren't so involved with the
more important task of closing the hatch.

Craig Fink

Brian Gaff wrote:

Though apparently not actually a serious problem, the way they have to
find leaks seems long and time consuming, something that may not be a
possibility to have if a serious leak occurred.

Is there no technology that could be used to find leaks, or at least pin
them down more accurately when they occur?

If you have access to the outside of a pressure vessel (like in a vacuum
test chamber on the ground) it's pretty easy. Either add a visible
coloring agent to the test gas or use a GC/mass spec to "sniff" for the
test medium.

I have never heard of such a leak on a Shuttle, though I have noted
comments about chipped windows in the past.

My gut feeling is that that odd sound that was heard may have something
to do with this problem.

How are wires etc, that need to get to aerials, passed through the body of
a craft to remain air tight? It occurred to me that a loose antenna that
might
look fixed, could easily tug on a cable and eventually break a seal.

On the U.S./European segments of ISS, most fluid lines and power/data cables
pass through the pressure vessel at the end cones which are not easily
accessible from inside the module. There's essentially no chance one could
tug on a cable or fluid line and break the seal because you can't reach it.
Furthermore, these cables and fluid lines all have thermal expansion and
vibration isolation features (like bellows or flex couplings) so an
accidental tug by crewmember digging around in the endcone probably
wouldn't harm anything.

Some intermodule lines run through panels adjacent to and surround module
hatches but those don't access vacuum; a leak there shouldn't cause a
pressure drop.

The mechanism by which the lines pass through the module is a fitting called
a "feed through". The power/data feedthroughs have connectors on both ends
and they are hermetically sealed; the conductors pass through what is
essentiall several inches of solid material and there is almost no chance
of any significant leak through the connector. Each end of the feed
through has pinned connectors and cables mate on both ends (internal and
external) to the feed through connector. Leaking AROUND the connector is
possible, depending on the design chosen to seal the feed through to the
pressure vessel.

Brian


--
Brian Gaff....
graphics are great, but the blind can't hear them
Email:

__________________________________________________ __________________________
__________________________________




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Reformed Aerospace Engineer
Remove invalid nonsense for email.

It would make more noise and be sucking stuff towards the leak. since it was
small it was hard to find.

This doesn't sound at all like what happened during the decompression aboard
Mir. The main evidence the crew had as to what module had the leak was one of
the crew actually saw the Progress strike that module. There first serious
evidence that it had the leak was when they had difficulty closing the hatch
due to all the air being sucked into the module.

Assuming "Dragonfly" was an accurate account here...

-A.L.