Tests this weekend to pinpoint slow leak on ISS

The astronauts this weekend will shut all the hatches between different modules on ISS so that ground controllers can try to pinpoint the location of a long term slow air leak.

This leak was first spotted in September 2019, when there were “indications of a slight increase above the standard air leak rate,” NASA said in the statement. “Because of routine station operations like spacewalks and spacecraft arrivals and departures, it took time to gather enough data to characterize those measurements. That rate has slightly increased, so the teams are working a plan to isolate, identify and potentially repair the source.”

While the leak rate is higher than usual, it is still within specifications for the station and poses no immediate danger to the crew, NASA officials emphasized. Astronauts also deal with leak simulations during training for their stays on the space station, which typically are about six months long.

The weekend test will allow them to identify where the leak is located. They will then be better able to find it, and mitigate it.


  • Jay

    More drilled holes? At least we can’t blame Nauka for this one.

  • Phill O

    The deep state has gone to space?

  • Steve Richter

    Could the space station be equipped with a propulsion module that could take it out of Earth orbit? Thinking it would be neat if the ISS could travel to the Moon, orbit it for a while, then return to Earth orbit.

  • Steve Richter: In a word, no. ISS was badly designed as a prototype interplanetary spaceship, even though that’s its only real purpose. It is mostly managed from mission control. It can’t do a flight to the Moon because much of its operation is controlled from the ground.

    Note that the Chinese space station is being built with this exactly in mind. No one thus should be surprised if at some point the Chinese upgrade it and use it to do a flight around the Moon.

  • mpthompson

    NASA should hold a competion for submitting creative ideas for isolating a slow leak on the ISS. Who knows, perhaps someone can come up with some creative method for determining where the leak might be.

  • pzatchok

    Its not the Biggalo module.

    That one is self sealing.

  • LocalFluff

    @Steve Richter
    No, that is impossible. The ISS can only function in low Earth orbit where it spends half of the time Earth’s shadow to cool down. Also, it is far too heavy to move out to the Moon with anything that can be launched. It’s mass is about 8-10 times that what went to the Moon during the Apollo missions.

  • Diane Wilson

    ISS does not have a propulsion unit. It used to rely on the Shuttle to boost it once in a while to maintain its orbit. I’m not sure how that’s being done now.

  • Jay

    They use the Progress re-supply spacecraft to boost the orbit. I would have to look it up, but I believe ESA’s ATV also had boost capability.

  • pzatchok

    The ISS was not designed or built with a linear thrust axis.

    Increasing its orbital speed is all that can be done with it. And even that is very risky.

    All that mass is essentially resting on each individual docking port.

  • Ryan Lawson

    Given all the little bits and pieces floating around in the station I would expect something as tiny as a sand grain could get into a seal to a main airlock and cause problems. I spent a bit of time working with vacuum chambers for research and any time I started to notice issues keeping pressure near zero I would go clean the main door seals and see an immediate improvement. But, this thing has so many linkages between modules and after so many docking bumps who knows if some of them have been kinked enough to open up a super tiny gap.

  • Michael Schnieders

    @ LocalFluff
    In regards to the first part of your statement, that is not quite accurate.
    There several times in the year where, due to the orbits inclination, the ISS will spend several days in uninterrupted sunlight. Also, even if the space station orbited at a near zero inclination, the station would spend more time in sunlight than in shadow. Due to the altitude of the orbit, as the space station passes over the Earth’s dusk/dawn terminator line the station remains in direct sunlight. the station will remain in sunlight for few more minutes before entering the Earth’s shadow, and then the same will occur as it leaves the Earth’s shadow. So, for a 90 minute orbit, with only a very few exceptions, time in sunlight far exceeds time in shadow.

  • Michael Schnieders


    it took me a few minutes, but here is a decent example…


  • LocalFluff

    @Michael Schnieders, I must correct you.
    Earth’s axis tilts 21½ degrees relative to the Sun.
    The ISS’ orbit has an inclination of 51½ degrees.
    21½ + 51½ < 90 i.e. never in polar orbit over the terminator.
    Thus, the ISS always spends half of each orbit in Earth' shadow. (The 450 km altitude over the 6,400 km radius planet of course means that it spends slightly more time in the Sun than in the shadow each orbit, but insignificantly.) I'm quite sure that it is designed to spend half its time in the shadow and that it would otherwise quickly overheat and become uninhabitable, and likely fail also mechanically and in other ways. They didn't launch and install more heat radiators than necessary.

  • Michael Schnieders

    @ LocalFluff
    from Spaceflightnow Dec. 13, 2017

    “If SpaceX is forced to delay the cargo launch again, the next chance to send the supply shipment to the space station will not come until late December. A period of constant sunlight in the space station’s orbit, known as a high solar beta angle, will prevent the outpost from receiving the Dragon cargo craft.

    “In a high solar beta, or a high solar angle regime, basically the ISS doesn’t see a sunset or a sunrise,” said Kirk Shireman, NASA’s space station program manager, in a briefing with reporters Monday. “It’s basically one long, long day, and it puts a lot of thermal constraints on the vehicle, so we try to avoid critical operations — dynamic operations — like spacewalks and vehicle dockings and undockings during this high solar beta.””

    to further example: https://www.youtube.com/watch?v=Hq35IP21Mwg
    also: https://www.universetoday.com/142187/the-international-space-station-rides-high-through-the-may-sky/

  • mkent

    ISS does not have a propulsion unit. It used to rely on the Shuttle to boost it once in a while to maintain its orbit. I’m not sure how that’s being done now.

    ISS does have a propulsion unit. It’s on the Service Module. It can be refueled by Progress vehicles and ATVs. Most often, however, the Progress (and formerly ATV) vehicles perform the maneuver directly to save wear and tear on the Service Module’s engines. (Note: the ATV has been retired.)

  • LocalFluff

    @Michael Schnieders
    I’d be damned, the precess the orbit so that it spends time over the terminator!
    Good to learn something new, thank you.

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