Minor Leak Being Investigated Aboard the ISS

Josh Fink writes "Space.com is reporting that the International Space Station has a minor atmosphere leak. 'An inspection of a vestibule bridging the station's new Harmony connecting module and NASA's Destiny laboratory indicated a slight air leak of about three pounds (1.3 kilograms) per day ..A close-up inspection of the vestibule seal by the station's three-astronaut Expedition 16 crew using an ultrasonic leak detector found no trace of a leak on Wednesday, [NASA spokesperson Lynette Madison] said. Studies of the station's overall internal pressure also found no signs of decay, she added.' While this is yet another technical issue with the ISS, when will this end? I am all for the space program, but there have been some major issues lately."

Comments

Comes with the territory

[SIGALRM]

I am all for the space program, but there have been some major issues lately

Being "for the space program" requires some acceptance of the massive risks inherent in manned space travel. If mechanical systems are design-simplified it may reduce points of failure.

KERMIt, a "Kit for External Repair of Module Impacts", is one of those simple systems being developed at Marshall Research to seal punctures in the ISS. It will enable crewmembers to seal punctures from outside damaged modules that have lost atmospheric pressure. Delivery of the kit is scheduled for next year. KERMIt is also useful for sealing leaking atmospheric seals as TFF article describes (more info here).

Re:Comes with the territory

[iminplaya]

Being "for the space program" requires some acceptance of the massive risks inherent in manned space travel.

You're not kidding. The submitter's complaint is like bitching about the Wright Brother's airplane not being able to fly 100 people across the Atlantic by the end of 1904. The thing is an experiment, ok? Some problems may be due to poor decision making, but I think we can still cut them some slack here. This is not like the Challenger disaster where I believe upper management committed criminal negligence for political expediency. They were warned about that impending failure to the point that the TV news reporters were discussing it before launch. So they got a leak. Use it to ventilate the bathroom.

Re:Comes with the territory

[Anonymous Coward]

The purpose of the ISS is to learn how to build and maintain large facilities in space. It is a learning process. My question to those that use issues like this as a reason to criticize the ISS is simple: Would you rather have this kind of problem come up on a lunar base where the crew was three days, not two hours from safety? How about on a Mars mission where there was no chance of sending repair parts or rescuing the crew? It is far better to discover issues like this, or the torn solar panel, or the metal shavings they found in an array rotary junction, now and figure out how to deal with it and prevent it from happening again in the wading pool of low Earth orbit rather than in the deep ocean of space.

I Agree!

[Anonymous Coward]

It's like, when I drive to Dallas to Houston I don't have any problems. But when NASA tries to build a space station in orbit stuff goes wrong!

What is up with that?

"when will it end?"

[taniwha]

hopefully never - the whole point is it's an engineering experiment, if nothing fails they won't learn anything, it'll just be a bunch of guys sitting around wondering what they're doing there

Re:"when will it end?"

[MightyYar]

Besides, learning that something got stuck on the seal before they connected the two segments would hardly be a valuable scientific discovery. That isn't necessarily the case. It would show that their current procedure of ensuring a clean seal is either not good enough, or the seal is not robust enough to handle unavoidable amount of contamination. In either case, it is better to discover this in low earth orbit than on the moon or on Mars.

Going to space is hard

[TooMuchToDo]

While this is yet another technical issue with the ISS, when will this end? I am all for the space program, but there have been some major issues lately."

Going to space is hard. It shouldn't stop us from doing it. Issues will crop up.

Problems never end

[YA_Python_dev]

I agree.

While this is yet another technical issue with the ISS, when will this end?

Never. When you build something big, hardware or software, you will have problems. You can't expect to have everything always work the first time.

When you encounter a problem you fix it, it's that simple.

Remember: "The perfect is the enemy of the good." -- Voltaire

Re:Problems never end

[Anonymous Coward]

When you encounter a problem you fix it, it's that simple.

And more importantly, you get better at fixing them. That's really why we're out there after all. We're gaining experience that can only be gained the real way.

Re:Problems never end

[david.given]

That said I have to wonder if the ISS could be bumped into a lower maintenance orbit and used as a hub for a bolo style rotating space station.

It's too low as it is --- there's enough air resistance that it has to be reboosted at intervals to keep it in orbit. (It has to be that low because otherwise the shuttles can't get there. They have lousy range.) Lowering the orbit any further would be very dangerous.

As for spinning it (you did mean bola, right? Unless you were actually thinking of giant robotic tanks, which I will admit would be quite cool), not only is it not designed for that and would fall apart, but if you want gravity there's plenty on Earth, where it's quite cheap. One of the main purposes for getting into space is to get free fall.

I rather regret that Mir was destroyed for purely political reasons. If the ISS was built as a set of add-on modules to Mir, gradually superseding Mir's own modules as they began to break down, construction could have gone a lot faster. Even if the Mir modules stopped working completely, they'd still have considerable value as salvage.

Rather than a trip to the moon, I would be far more excited to hear about an ISS greenhouse that does all of the air and water maintenance.

I want a balloon. A ten or twenty metre inflatable habitat module, semitransparent hopefully, in which plants a grown. Inflatables and plastics are the future of spaceflight; look at the cool stuff that Bigelow Aerospace are doing. But even they are simply replicating existing modules using inflatables. It ought to be possible to use the new materials to radically change the way space stations are built. How about a 100m wide spherical envelope, full of air, with your space station built inside? Now, that would be cool, particularly once you have a decent amount of plant life in there...

these problems are the reason we need ISS

[Anonymous Coward]

guys... I work for nasa on the space station program... i am amazed at how people frame the detection and fixing of problems on the space station are such a negative thing... the space station construction is so incredibly difficult and complex... and when we have issues, people point them out as never ending. This is the 2nd space station... compare that to the 2nd airplane.

And the biggest thing that amazes me is that these problems are the biggest reason to have the space station!!! We have to learn how to fly in space long term... and fix problems just like these!! what kind of problems do you think we will have when we go to the moon and mars?? do people honestly think if we just drop what we are doing and took off trying to get to mars, we would find out just how much learning we have left to do.

overall, i think the american public is left feeling ashamed of the problems they see on the ISS, instead of being proud of the accomplishment because they don't really comprehend just how insane the Apollo successes were, and how ahead of their time they were. We really do have a lot left to learn about flying in space and fixing things in space with the materials in place, and unless we want to take insane risks and costs like were done in the Apollo program, we need to do that with the space station.

these problems... their detection, isolation, and recovery, are the greatest asset of the space station.

Re:these problems are the reason we need ISS

[Anonymous Coward]

I know you guys are working with a neutered budget, but that doesn't mean they had to pawn off your [shift] key. That was totally lame on their part.

Re:these problems are the reason we need ISS

[popo]

I thought I issued a company-wide memo about NASA employees surfing Slashdot during work-hours.

Please come down to my office right away.

pin sized hole hard to reach

[wizardforce]

While this is yet another technical issue with the ISS, when will this end? I am all for the space program, but there have been some major issues lately."

it's probably a leak about the size of a needle hole hidden somewhere out of reach with a simple leak test. it wouldn't need much, 1.3 kg of air is about 1 cubic meter in size leaking over a day's time. considering there's about 10N/cm^2 force and the force exerted by a moving column of air is mv^2 while the density m is 1.28 kg/m^3 solving for the size of a hole required to vent the gas is about 2mm in diameter if back of the envelope calculations are correct [probably not but you get my point]

Re:pin sized hole hard to reach

[kebes]

Sounds about right. I just ran it through some simple effusion equations (kinetic gas laws). Assuming that the amount of air escaping is 1.3 kg (1.14 m^3), and that the volume of the room it is escaping from is ~200 m^3 (apparently the total final size of the ISS is 1000 m^3), and that the ISS is pressurized to 101.3 kPa (the Wikipedia article says that it is), then we can calculate the time for 1/200 of the air (0.5%) to escape, as a function of the hole diameter. It turns out that a hole of diameter 0.15 mm will lead to that kind of rate of pressure loss (1 m^3 in the first day).

Needles to say, the effusion equations have various assumptions built into them, and I had to make all kinds of assumptions about the values... but at least to within order-of-magnitude, this suggests a pinhole-sized leak.


Details for anyone who cares: The effusion equation can be derived similar to the conventional gas law expressions, by calculating the number of molecules per unit area that impinge on a wall section of a certain size (the hole). (We assume a container in vacuum, so that any molecule that impinges on the hole is lost irreversibly to the outside.) The equation, as you might expect, turn out to be exponential decays (since the derivation incorporates the decreasing internal pressure as air is lost):

N(t)/N_total = exp( -(A/V)*sqrt(k*T/2*pi*m)*t )

or

t = ( -(V/A)*sqrt(2*pi*m/k*T) )*ln(N(t)/N_total)

where:
t, time (until the given loss of atmosphere)
V, volume of container
A, surface area of hole
m, mass of gas molecules
T, temperature (~300 K for room temperature)
k, Boltzmann constant
N(t), # molecules at time t
N_total, total # molecules (initial quantity)

Space is hard

[geekoid]

but to quote some guy:
"We choose to go to the moon. We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win, and the others, too." - JFK

http://www.quotesandsayings.com/sjfk.htm

Yeah, it's hard and complex. We will learn how to make maintenance of those systems routine and automated. We will continue to look forward, we must less we stagnate and die. The fate of the Dinosaurs will be our fate as well if we don't diversify off this rock. There are a lot of steps between here and the next habitable planet. Whether it's habitable because nature forms more planets like ours, or habitable because we terrorformed it makes no matter.

Pound != 0.454 Kilogram on the ISS

[corsec67]

FTA: "a slight air leak of about three pounds (1.3 kilograms) per day".
I hate to break it to this reporter, but on the ISS, a pound is a large number of kilograms, since they are in microgravity. Pound is a unit of weight, and gram is a unit of mass. The conversion between them depends on the gravity that the object is experiencing, which in this case is almost none, so the 1.3 kilograms of air is almost 0 pounds.

Movie-inspired salvation

[Lurker2288]

I totally saw this in a movie once. All they need to do is open a prominently featured can of Dr. Pepper and let the soda spraying out through the hull show them where the leak is. Caveat: this plan carries a small risk of vaccuum-freezing Tim Robbins.

Let's give up on all research.

[palegray.net]

Quoth the poster: While this is yet another technical issue with the ISS, when will this end? I am all for the space program, but there have been some major issues lately.

Yet another round of bugs were discovered in several major operating systems and userland packages. I'm all for operating systems, user software, and advances in computing technology. but there have been some major issues lately. I vote we give up and go back to the abacus and using smoke signals to communicate.

Re:Pound != 0.454 Kilogram on the ISS

[turgid]

Pound is a unit of weight, and gram is a unit of mass.

My dad, who is from the Olden Days when people used pounds and inches, and an Engineer, says that there exists a "pound-mass" and a "pound-force" and the reader is expected to have the wit, depending on context, to distinguish between them.

Re:Mod parent up!

[MichaelSmith]

Thats pounds mass. Gas quantities were measured that way all through the Apollo program.

Re:Pound != 0.454 Kilogram on the ISS

[Detritus]

It's about 0.1 slugs of air per day, or 6.6 stone per fortnight. Are you happy now?

failure is not an option?

[sohp]

Seriously, the story of the space program is not "we did so well nothing went wrong" but, "when things went wrong we used our guts and brains and fixed them"

Examples:

Gemini 8 thruster stuck. Armstrong was able to regain control and return safely home.
Apollo 11 landing 1201 and 1202 program alarms. Programmers on the ground and flight engineers were able to rapidly determine that the alarms posed no threat and the landing continued to success.
Apollo 13. Catastrophic explosion disabled the service module. The astronauts returned home safely using the LEM as a lifeboat and some creative navigation.
Skylab launch: Ripped off a solar panel and part of the outer skin. Astronauts were able to rig a replacement screen to cool inside of the lab and open the other solar panel that was stuck partly open. Three expeditions extended the time in space records and recorded what was then the most detail solar observations ever.
STS-49: Multiple attempts to capture and return an Intelsat satellite failed, but a final attempt involving the shuttle commander flying directly to the satellite and it being hand-captured by 3 spacewalkers succeeded.

There are plenty more, including the recent working solving problems with stuck and torn solar panels.

Incidentally, these kinds of things are why I favor human spaceflight over robots for complex and difficult challenges.