Home » This Is What A Coolant Leak Looks Like In Space

This Is What A Coolant Leak Looks Like In Space

Soyuzleak Top

We’ve all dealt with coolant leaks, right? Wake up and find an expensive-looking puddle of greenish liquid under your car, or a hot, steamy shine coating your entire engine bay in maple syrup-smelling coolant? They’re no fun. All coolant leaks tend to end up on the ground, though, somehow, thanks to gravity. But have you ever wondered what a major coolant leak would look like in space? Of course you have; you’re human. Well, thanks to a spacecraft docked to the International Space Station, you don’t need to wonder any more. It’s a mess.

The spacecraft in question is the Soyuz designated MS-22, one of the two spacecraft that are always docked to the ISS, acting both as ferries to the station from Earth, and, when docked, acting as a way back home, both for scheduled returns and in case of emergencies. A Soyuz can carry up to three crew, and with the current complement of seven crew on the station (four came up and can return in the SpaceX Crew Dragon spacecraft) a working Soyuz is needed to provide safe evacuation of all crew.


The Soyuz has been spraying out some sort of frozen flakes for hours; the particles were determined to most likely be coolant coming from one of the Soyuz’ external cooling manifolds, two of which make up part of the spacecraft’s single coolant circulation loop, which includes a radiator that wraps around the aft section of the service module. Pressure sensors in the cooling loop showed low readings, and despite the leak, currently the Soyuz’ temperature is within acceptable limits.


A spacewalk was scheduled but was cancelled when the leak was discovered, to prevent astronauts and cosmonauts from being potentially covered in spraying coolant. The Canadarm2 robotic arm was tasked to get closer video footage of the leak to try to determine its source.

Here’s some NASA footage of the leak in action:

That’s a hell of a leak! It’s not clear just yet what caused it, though a micrometeorite strike is a possible explanation.

The humble Soyuz has the longest and safest track record of any crewed spacecraft, so this is a very unusual situation. No one has died in a Soyuz since the Salyut 1/Soyuz 11 tragedy of 1971 when a faulty valve opened during reentry, causing the crew of three to suffocate after their successful mission to humanity’s first space station, Salyut 1.

While the ISS crew isn’t in immediate danger, if this Soyuz is found to now be unusable for re-entry, Roscosmos will need to launch an uncrewed Soyuz and dock it to the station remotely to replace the damaged Soyuz, which would be a first for the ISS.

A spacewalk is planned for December 19, and the Soyuz will be inspected remotely to determine what the plan is. We’ll update when NASA and Roscosmos figures out what they want to do, which probably won’t include some JB Weld, duct tape, and a stern warning to not leak, ya bastard.


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26 Responses

  1. “a stern warning to not leak, ya bastard.”

    I think Nulon really needs to expand their “Ya Bastard” product line:

    For coolant leaks: Stop Leak’n Ya Bastard!

    Car wash: Ya Filthy Bastard!

    Transmission fluid: Shift Ya Bastard!

    Brake fluid: Stop Ya Bastard

  2. I always wonder how coolant escapes in space? I would think it would freeze up and have a blockage rather than leak. What exactly is the temperature in the vacuum of space. And since space is so cold why does it need coolant, shouldn’t it need heatant? I also wonder why a space station is built in pieces that arent several escape pods or at least able to float in space with self sustained emergency support until rescue can be attended. Sort of like different RVs in a RV Park as opposed to a single support like a coop building?

    1. To answer your second question, the heat shielding to survive reentry would be incredibly heavy to add to the modules themselves to use as escape pods. Hauling that up there would have take way more missions, assuming it wasn’t to heavy to be possible at all.

    2. Space is cold, but that’s not the problem, gotta look at the other direction. Items in space, in the sun, get HOT. Once they are HOT, then how do they cool?

      Conduction? Not really. Everything is in contact with everything, and its all being heated by the sun.
      Convection? Nope. No molecules in contact to allow heat transfer away
      Radiation? Uh-uh. That’s what’s heating it up, sun’s radiation. Not going to be able to cool with that bastard beaming down on ya.

      Insulation helps, blocking the sun’s rays definitely helps, the rest is done with radiators.

      1. Yes radiation. Infrared radiation is the only practical way to dump unwanted heat without contact with an atmosphere, ocean or ground.

        IIRC the key is to orient the radiators perpendicular to the sun. I suppose one could also use the shadow of the solar panels or other structures.

        1. I was recently wondering about that. Say you found yourself naked in space but somehow not dying from the vacuum or lack of oxygen. You would either heat up from the sun or, if you were behind something that blocked light you would probably cool pretty slowly. I wonder what the rate of cooling would be?

  3. I thought it was Start Ya Bastard rather than Not Leak Ya Bastard.

    Ah Kirk, my old friend. Do you know the Klingon proverb that tells us revenge is a dish that is best served cold? It is very cold in space.

    1. The title doesn’t bother me, but the fact that the NASA logo satellite could’ve made a complete orbit if that looping .gif had just a few more frames is really triggering my OCD.

  4. Oh, it’s way worse than just a messy coolant leak. Spraying material in space also means: thrust! That off-axis thrust is probably playing havoc with the attitude correction system on the station and is definitely causing it to use up fuel that it should be conserving for normal station-keeping and attitude correction. Large low-earth orbit objects like the space station need a healthy supply of fuel to counteract all the forces acting on them and trying to pull them down to the earth such as drag from molecules in the outermost layers of the atmosphere, solar wind, and good ole gravity, of course.

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