While watching Soyuz exp. 37/1 land, I was struck with a thought: that capsule looks an awful lot like a submarine.

enter image description here

This seems to be a problem if the crew ever needed to make an emergency landing onto water - water is generally softer than permafrost for emergency landings. But submarines tend to sink, after all.

What would happen if a Soyuz landed in water?

  • $\begingroup$ Not submarine! Diving bell! (Down by the Riverside, anyone remember that live action Hamster, Guinea Pig, etc kids TV series?) $\endgroup$
    – geoffc
    Commented Nov 11, 2013 at 17:27
  • $\begingroup$ Similar: space.stackexchange.com/questions/1664/… $\endgroup$
    – Everyone
    Commented Nov 12, 2013 at 8:03

3 Answers 3


Soyuz was designed and tested for water landing capability (the unfortunate lake landing notwithstanding):

Zond 5 splash down in the Indian ocean, 1968

The photograph is attributed to Zond 5 unmanned mission within the lunar L1-Zond effort: http://en.wikipedia.org/wiki/Soyuz_7K-L1

Some additional curious bits of info on Zond 5: there were some life turtles riding this probe around the moon and back. All survived, despite reentry at near escape velocity. Also, the weather at the recovery site was rather bad and there was an US military vessel nearby trying to take a look at what's going on and possibly snatch the probe. Despite this, the recovery vessel "Borovichi" was able to locate and recover the probe in just 10 hours overnight.

There also existed a special water landing facility at Feodosia to develop this capability.

Water landing tests are still performed, occasionally:

Water landing test Southern Ural reservoir, 2011


In fact, the Soyuz is designed to make an emergency water landing, and has done so once by accident, when Soyuz 23 landed by accident on a frozen lake. The landing didn't go particularly well, the parachute filled with water and caused the escape hatch to be covered in water. A complete account can be found here, but let's just say the experience was less than pleasant.

  • $\begingroup$ Kudos to @Erik for the helpful edit! $\endgroup$
    – uhoh
    Commented Mar 7, 2018 at 5:37
  • 2
    $\begingroup$ @uhoh no worries. I was getting ready to write a comment saying the link was still broken, when I decided it would be better for everyone if I just took the effort to find a new link. $\endgroup$
    – Erik
    Commented Mar 7, 2018 at 17:08

Almost certainly it would sink. Not that that would be a problem depending on how long it took to recover it. One early mission, Soyuz 23, did land in a lake and it took until the next day to recover the craft and extract the crew.

The US Apollo capsules (similar in size) would have sunk. They had 3 floatation bags that inflated on splashdown so it would stay upright and afloat until the recovery craft could arrive. (Wikipedia)

Russia doesn't have the convienent access to oceans for recovery that the US has. And probably in the early days, the Soviets perfered the security of landing the capsules in their interior where they could control the news of the outcome (which wasn't always positive -- Soyuz 1 & 11, for example).

  • $\begingroup$ That must have totally sucked for the crew. Knowing they are fine, just underwater, and have supplies for X amount of time... Can they find us in time? $\endgroup$
    – geoffc
    Commented Nov 11, 2013 at 17:28
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    $\begingroup$ The Apollo capsules would not have sunk. Capsules similar in shape to the Apollo capsule have two stable floatation positions -- right side up (stable 1), and upside down (stable 2). Obviously, stable 2 is not conducive to letting the crew get out of the capsule, which is why the floatation balloons existed -- to right the capsule. They certainly would not have provided enough buoyancy to be responsible for it floating. $\endgroup$
    – Tristan
    Commented Nov 11, 2013 at 17:33
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    $\begingroup$ @Tristan: you mean besides the fact the balloons are out of water in stable 1 position right? $\endgroup$
    – Joshua
    Commented Mar 11, 2017 at 0:14
  • 1
    $\begingroup$ @Joshua yes, they are. The key point is that when upside down they would be underwater, their buoyancy would make it unstable in that position and they would end up being upright. $\endgroup$
    – Baldrickk
    Commented Mar 7, 2018 at 12:05