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Space Station Leak Found, Fixed 225

Posted by simoniker
from the no-more-whooshing dept.
Rommel writes "NewScientist.com is reporting that the cause of the leak in the International Space Station has been found and fixed. The leak was found in a hose in the Destiny lab module. The hose was used to equalize pressure and eliminate fog between two panes of a window. While the leak was so slow it was unlikely to pose a direct threat to the crew for months to come, some equipment on the ISS is only certified to operate above a certain air pressure. The leak was originally mentioned on Slashdot a few days back."
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Space Station Leak Found, Fixed

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  • by BaronAaron (658646) on Monday January 12, 2004 @02:23PM (#7954233)
    Destiny [space.com] was designed and made in the US.
  • by therealcaf (697590) on Monday January 12, 2004 @02:24PM (#7954258)
    according to the article
    The station's air pressure had dropped from the normal 14.7 psi to 14.0 psi. NASA have emphasised that the crew's health was not in danger, but some onboard equipment, including an air monitor, is only certified for use above 13.9 psi
    it would seem that things were pretty close. but keeping in mind that it was only losing .03 psi per day it doesnt seem that serious. they would have had 33 more days to find it atleast.
  • by CrazyTalk (662055) on Monday January 12, 2004 @02:28PM (#7954295)
    better check your math - in 33 days they would be down to 13.0 psi.
  • by mzs (595629) on Monday January 12, 2004 @02:40PM (#7954441)
    Here is another good article [news.com.au] from The Austrailian with more details. The pressure rose from 13.92 psi to 14.11 psi when the leak was sealed.
  • 14.0 PSI? (Score:5, Informative)

    by kscguru (551278) on Monday January 12, 2004 @02:54PM (#7954591)
    Normal pressure is 14.7 PSI. They are concerned at 14.0 PSI. Their equipment is not rated to work at 13.9 PSI.

    Guesstimating from some info here [cozine.com], Denver, CO is ~12 PSI. A tall mountain in the US is ~10 PSI at the top.

    Lousy, cheap NASA equipment! It wouldn't work down here on Earth anyways.

  • Re:pressure (Score:5, Informative)

    by EvilTwinSkippy (112490) <yoda&etoyoc,com> on Monday January 12, 2004 @03:14PM (#7954792) Homepage Journal
    Actually the crew could work normally until about 1/2 of an atmosphere. If the change is gradual enough, your body build up extra red-blood cells to compensate. Mountain climber in the Himalayas actually park at camp for about six weeks to 'acclimatize' to the reduced atmosphere.

    Most people would still need some bottled Oxygen to get up to the top of Everest though, at around 1/3 of an atmosphere. When the pressure gets that low, your body has trouble metabolizing fast enough to maintain temperature.

  • Re:Damn... OSR (Score:3, Informative)

    by outcast36 (696132) on Monday January 12, 2004 @03:36PM (#7955004) Homepage
    This is in reference to Simpsons episode CABF03 The Great Money Caper.

    Mir cosmonauts throw the sturgeon from the station in a fit of rage.... Read more here [snpp.com].

    insert russian profanities
  • by HeghmoH (13204) on Monday January 12, 2004 @04:57PM (#7955619) Homepage Journal
    A small correction on the Apollo 1 fire. The fire hazard from low-pressure pure oxygen is comparable to the fire hazard from a full-pressure atmospheric mix. I believe there are physiological effects to low-pressure oxygen that make it less desirable.

    What happened with Apollo 1 is that it was supposed to use low-pressure pure oxygen in flight. However, on the ground, they couldn't do that because the capsule was only meant to take pressure pushing out. If they had used low-pressure oxygen on the ground, it would have been crushed by the outside air. So they just increased the pressure. Oxygen at 3psi is ok, but oxygen at 16psi is an incredible fire hazard. Fire starts, everybody dies.
  • Re:pressure (Score:5, Informative)

    by tmortn (630092) on Monday January 12, 2004 @05:37PM (#7956115) Homepage
    No, just the fact the crew is 'rated' to lower pressures for operation. There is a flight reg for a repress to 14.4 psia if the pressure drops to 13.9. The 13.9 is not the crew danger redline. There are several pieces of equipment on board that have the lower pressure operational limit set at 13.9... ie thats as low as they are certified to work with no problem. at 13.95 or so they start to be powered down in case the pressure continues to drop.

    The reason is due to thermal buildup. Without gravity you have no coreolis effect, most commonly recognised as the idea that hot air rises. In ziggy hot air does not rise it just gets hot, thus you have to have thermal transfer by contact of some sort, IE air blowing or contact with a heatsink ( water loop ) etc... which is the reason for those huge radiators on the station.

    At lower pressure there is less thermal transfer with the air which means greater heat buildup in the electronics could cause a problem or possibly an unrecoverable malfunction.

    Genrenally speaking these limits are VERY CAUTIOUS. Much of the equipment has no redundancy and could only be replaced by flying it up from the ground... something very difficult to manage payload scheduling wise even if shuttle were making flights and next to impossible with Soyuz/Progress launches. Thus you don't risk even the possibility of an equipment failure even though much of the equipment would likely operate just fine in near vacume conditions.

    To have an idea regarding crew limits consider the fact suit pressure for EVA's is 4.3-5 psia, the new hard suit concept allows for 8.3 ( no pre-breathing ). Either consisting of an environment which could be created in very short order on the station. Of course this requires shifting the concentration of oxygen... close to 100% in the case of the 4.3 I belive, which is dangerous. The 8psia range requires ~32psia which is only a few percentage points above nominal environment on the station.

    Thus the pressure drop at that slow of a rate presented a far more immediate danger to the equipment than it did to the crew. The crew was not worried nor were the flight control teams worried about the crew for the simple reason the crew was as yet not in any immidiate danger as it would have taken weeks at the recorded rate of loss to place the crew in danger just had they not undertaken to replace what was lost... they also have plenty of spare oxygen to add and thus it would have taken months for this leak to depleat stores to the point where the crew would have been at risk.

    The engineers didn't have the head in the clouds or no concern for the Crew. Crew safety on the station takes precedent over EVERYTHING else.
  • by becker (190314) on Monday January 12, 2004 @05:56PM (#7956376)
    With reduced pressure, the thermal capacity of the cooling air is proportionally reduced. Combined with changes in forced air flow and microgravity not creating convectional cooling, you can have long-term overheating issues with equipment that consumes very little power.

    This is solved on satellites with conductive cold/hot plates, but that results in much heavier equipment.

    Regarding leakage rates, it's very difficult to estimate leak flow rates. The flow might be proportional to pressure squared, or cubed. If it's in an elastic seal, it may completely re-seal when the pressure drops to a specific level.

    Humans can function at elevations of about 5psi (see the other posts about mountain climbers), and survive on a little less. Since O2 is less than 20% of the atmosphere, you can theoretically live on 1psi of pure O2. But secondary effects are killers at that low pressure, such as keeping enough moisture in the lung tissue. When near-pure O2 is used, it is usually at about 3psi or nearly the partial pressure of O2 at sea level.

  • Re:pressure (Score:5, Informative)

    by delcielo (217760) on Monday January 12, 2004 @06:17PM (#7956615) Journal
    The truth is that above around 26,000 feet there is no amount of acclimatization that will compensate for the diminished oxygen/pressure. That's why they call it the "Dead Zone;" because essentially, you're dying. What happens is your cells start to deteriorate, becoming unable to contain fluids. Your brain starts to swell from the uncontrolled fluid buildup (High Altitude Cerebral Edema). Your lungs begin to do the same (High Altitude Pulmonary Edema). The only fix is oxygen and pressure.

    When you get above around 30,000 feet, you start running into funny little things like needing the air/oxygen forced into you with positive pressure, rather than the kind of "on-demand" oxygen setups that are commonly used. If I remember correctly, this is related to pressure; but is not the same issue that you get with pressure higher up, where you're worried about the blood's ability to contain its nitrogen, and thus, about the blood boiling.

    Scary stuff.
  • Re:pressure (Score:2, Informative)

    by tho 1234 (709100) on Monday January 12, 2004 @10:10PM (#7958684)
    Just to nitpick, the coriolis effect has absolutely nothing to do with gravity or rising gases. Its a "fictious force" that occurs as a result of observations taken in a rotating (ie not an inertial system) reference frame, such as the rotating earth. In everyday life, you do not experience any coriolis effect; if you did you would be aware that the earth is rotating under you- Instead, you're probably confusing the coriolis effect on global mases of air, which results in circulation cells that span vast distances... What you're describing, the fact that hot air rises, is simply due to the difference in density of the heated gas, ie basic fluid mechanics.

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