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Wikipedia's Yuri Gagarin says:

At about 23,000 feet (7,000 m), Gagarin ejected from the descending capsule as planned and landed using a parachute.

and the section Vostok_programme; Vostok 3KA says:

After one orbit, the descent module successfully re-entered the atmosphere, the mannequin was safely ejected, and the dog and other specimens landed separately in the descent module by parachute.

and this answer references Wikipedia explaining that the "ejection seat" of Vostok was removed in Voskhod.

Question: How did the Vostok ejection seat safely eject an astronaut from a sealed space capsule?

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  • $\begingroup$ You're assuming that the capsule was sealed, as in welded shut or something. That just makes no sense. $\endgroup$ – RonJohn Jun 17 at 16:22
  • $\begingroup$ @RonJohn that doesn't follow from what's actually written in the question. $\endgroup$ – uhoh Jun 17 at 16:57
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    $\begingroup$ what else could it mean? After all, fighter pilots had been ejecting from sealed airplanes for quite a while before 1961. en.wikipedia.org/wiki/Ejection_seat $\endgroup$ – RonJohn Jun 17 at 17:01
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    $\begingroup$ "atmospheric reentry at 8 km/sec ≠ flying an airplane" #1 The capsule isn't travelling at 8 km/sec through the atmosphere. #2. No one in his right mind would put the capsule hatch facing the wind. $\endgroup$ – RonJohn Jun 17 at 23:30
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    $\begingroup$ Remove the three instances of the word "sealed" from the Subject and Question. Notice the difference in tone. $\endgroup$ – RonJohn Jun 17 at 23:55
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According to this NASA page someone was killed when his space suit was ripped during a test of the ejection system.

Korolyovs [Korolevs] reaction to Dolgov's death was to take a number of urgent and clever measures. First he had the exit hatch made larger. Secondly, he increased to two seconds the interval between shooting off the hatch and the operation of the ejector mechanism.

But blowing off the hatch and ejecting the seat with the cosmonaut was not all.

The Vostok capsule was pressurized with nitrogen and oxygen to about 1 bar. The air pressure at 7000 m height is about 0.41 bar. To avoid injuries caused by the explosive decompression, a pressurized suit with closed helmet and gloves were worn. There is too little oxygen at 7000 m for a human without altitude adaption. When ejecting the seat, the suit was disconnected from the life support system of the capsule and sealed to retain pressure.

Cables for medical telemetry and for voice communication (microphone and earphones) were disconnected too.

The pressure difference from inside the suit to outside at 7000 m was about 0.59 bar, the suit was not very flexible but only for few minutes. The air inside the suit was breathable for the short time of fast descent from 7000 m to about 2500 m without oxygen supply or carbon dioxide removal.

At a height of 2500 m and an air pressure of about 0.75 bar, the cosmonaut could open his helmet to breathe fresh air with an oxygen partial pressure of 0.16 bar. The pressurized cabins of passenger airplanes are operated at about 0.75 bar.

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    $\begingroup$ Sounds quite exciting all by itself, maybe the scariest part of the whole mission! $\endgroup$ – uhoh Jun 17 at 10:17
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    $\begingroup$ @David Richerby thanks for editing, looks much better now! $\endgroup$ – Uwe Jun 17 at 14:46
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    $\begingroup$ I wonder if there was an automatic suit ventilation below 2500 m. If an unconscious cosmonaut failed to open his helmet, he would fade away due to low oxygen and high carbon dioxide in the suit. $\endgroup$ – Uwe Jun 17 at 14:52
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    $\begingroup$ @uhoh But these problems were very similar to an U-2 pilot wearing a pressurized suit using the ejection seat in a height above 7000 m. $\endgroup$ – Uwe Jun 17 at 17:09
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The hatch blew off and the pilot was ejected in a seat.

enter image description here

He then separated from the seat and descended on a parachute.

This was all kept quiet because of the contemporary FAI rules about manned spacecraft.

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    $\begingroup$ Note that fighter aircraft from that era were already using rocket-powered ejection seats to escape from a sealed pressurized cabin in a hurry, just as they are today; it was pretty typical for an explosive charge to eject the canopy a fraction of a second before igniting the seat motor. $\endgroup$ – Russell Borogove Jun 17 at 0:54
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    $\begingroup$ Canopy breakers seem to be typical on planes designed for low-level attack operations, where the brief delay after blowing the canopy might make a life-or-death difference. $\endgroup$ – Russell Borogove Jun 17 at 1:00
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    $\begingroup$ My favorite ejection seat story is harrowing, but everyone survives: gallagherstory.com/ejection_seat $\endgroup$ – Russell Borogove Jun 17 at 1:19
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    $\begingroup$ @uhoh I do not know. The source I used just said "jettisoned", perhaps I was assuming too much when I said "blew off". $\endgroup$ – Organic Marble Jun 18 at 0:49
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    $\begingroup$ This personal narrative says "blew off" but it's translated. spaceflight.nasa.gov/outreach/SignificantIncidents/assets/… $\endgroup$ – Organic Marble Jun 18 at 0:55

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