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Russian official: Soyuz leak possibly caused by micrometeorite hit

According to Sergei Krikalev, who heads Roscosmos’ manned program, the leak of coolant from the Soyuz capsule docked at ISS could have been caused by a micrometeorite hit.

Sergei Krikalev, a veteran cosmonaut who serves as the director of crewed space flight programs at Roscosmos, said a meteorite striking one of external radiators of the Soyuz MS-22 capsule could have caused the coolant to escape.

The malfunction could affect the performance of the capsule’s coolant system and the temperature in the equipment section of the capsule but doesn’t endanger the crew, Krikalev said in a statement.

Krikalev said Russian flight controllers were assessing the situation and following temperature indicators on the Soyuz. “There have been no other changes in parameters on the Soyuz spacecraft and the station, so there is no threat for the crew,” he said.

The “equipment section of the capsule” is its service module, not its habitable orbital module or descent module.

Krikalev, the first Russian to fly on the space shuttle and occupy ISS, is a generally very reliable source. He is speculating, but not wildly but based on what is so far known. The upcoming inspection of the Soyuz using an ISS robot arm will soon tell us whether he is right or not. Krikalev also said that the inspection will tell them whether this capsule can be used to return its astronauts to Earth.

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  • Col Beausabre

    It couldn’t possibly be shoddy workmanship by a drunken worker

  • David Eastman

    A sudden leak of that magnitude out of nowhere when it had already been on orbit for some time, I’d rate a micrometeorite impact as far more likely than a workmanship defect. It was in fact my first thought when I heard about it. But we are indeed far past the point of “oh surely not” on their manufacturing being at fault.

  • Edward

    David Eastman wrote: “But we are indeed far past the point of ‘oh surely not’ on their manufacturing being at fault.

    Considering that it took a while for the hole in that one Soyuz to open up, a few years back, I think this is a correct analysis. We can only hope that the Russian quality control has improved over the years, because we don’t have a lot of direct evidence that it has.

  • Frank Solomon

    For this coolant leak, mass accelerates out of the Soyuz. That means the Soyuz has a reactive, opposing force placed on it – probably “small”, but definitely unwelcome. The Soyuz docked at the ISS, so the ISS also experiences this force. The ISS crew / ground crew probably planned for this, but even if they did not, and even if this new force is “small”, they will have to find a way to balance the force, or ISS will (tend to) start tumbling.

  • Edward

    Scott Manley has video of the leak throughout this video: (9 minutes)

    Frank Solomon,
    This small new force is there, and it does need to be balanced, and the total torque is larger if the source of the force is farther from the center of mass than if it is closer. ISS has some reaction wheels that handle attitude control. There are a number of forces and torques that act on the station, and the usual attitude is to fly with one side constantly facing Earth, so ISS is constantly rotating relative to the inertial reference frame. These reaction wheels are always kept busy, so the effects on the attitude control system are low on the list of concerns of the controllers. ISS has automatic control systems that can handle it.

  • Jeff Wright

    Each Soyuz does have a pistol

  • Chris

    It’s not mentioned that I see, but what is the chemical coolant being released? Can this spray cause corrosion or other unwanted reaction to the surfaces it lands on?
    Are there optical components that need to be protected?

  • Jay

    It is either water, or “Isooctan LZ-TK-2”. You can see details in the December 15, 2022 Quick space links.

    I too wonder what Isooctan is and Fisher Scientific has it listed as: Isooctane, or 2,2,4-trimethylpentane, is a toxic, flammable, volatile, organic alkane, and an isomer of octane. Available in various quantities and reagent grades, it is an anti-knocking agent in gasoline. Other applications include use as a non-polar solvent.

  • Edward

    Chris asked: “ Can this spray cause corrosion or other unwanted reaction to the surfaces it lands on?
    Are there optical components that need to be protected?

    Any substance can have unwanted affects to the surfaces is lands on. It isn’t only lenses or windows or even mirrors that are optical. The solar arrays depend upon sunlight not being reflected away or absorbed by any molecules landing on them. The same goes for thermal radiators, where the radiative properties are those of the surface material, and water or other molecules can change the amount of thermal radiance they get; these, too are optical surfaces. Thermal blankets have the same problem, as they are designed to maintain a certain temperature on their insides, and if they radiate their outer surface differently, being optical surfaces, the inside surface maintains a different (though perhaps only slightly different) temperature. In fact, you can think of every exposed surface as an optical surface that affects the overall thermal properties of the space station, even if only slightly.

    It is similar to Frank Solomon’s question about the forces, thus the torques, applied by the leak to the space station. Small as these effects are, they are definitely present.

    This is one of the reasons that spacecraft are made in the controlled environments of cleanrooms. Along with dust, fingerprints, and other material contaminations, we try to limit these kinds of volatile materials from condensing on the inside and outside surfaces. The thermal engineer designed his system carefully, and we don’t want to upset that in a way that causes problems with the operation of the spacecraft.

    When something like this happens, a lot of controllers are watching to see how their own systems are affected.

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