Are there any published numbers for any crew vehicle for the probability of LOC (loss of crew) given the launch escape system has been activated? I am interested in both design goal numbers and projected numbers.

  • $\begingroup$ Very interesting question! We might learn something about different nations' and corporations' views on launch-phase risks and how to deal with them. $\endgroup$ Commented Feb 3, 2019 at 3:22

1 Answer 1


Normally there are very safe and well tested and the Crew could abord safely at any time. But there are of course exceptions like the Space Shuttle which didn't have a Launch escape system. But of course, there are exceptions like the ejection seats of the Gemini program. There were tested as much as NASA would probably do with anything but there were tested in a 70% Nitrogen, 30% Oxygen environment and the Final Gemini capsule used a 100% Oxygen. So an abort would have likely set the Crew on Fire and burned them to death before they could land safely.

EDIT: Sorry totally forgot the source. I think that Everyday Astronaut put it pretty nicely together in this Video

  • $\begingroup$ When the hatches were ejected just before the seats, the pure oxygen would escape from the Gemini capsule very rapidly. $\endgroup$
    – Uwe
    Commented Feb 23, 2019 at 15:43
  • $\begingroup$ @Uwe Yeah sure but it still would take at least idk. 1/6 of a second or so and that would (I think) still be enough time for the Fire to catch on to them, wouldn't it? $\endgroup$ Commented Feb 23, 2019 at 16:39
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    $\begingroup$ @Dragongames - the flight suits are supposed to be flame retardant but even if they do burn in 100% O2 remember sustained burning requires heat and the eject cycle involves blasting through the air cooling everything off. So most likely scenario is brief charring to exposed surfaces that is blown out as ejection pyrotechnics fire. This is also why many conventional ejection systems can afford to produce brief bursts of cockpit fire during operation as long as nothing on the seat is energetic enough to sustain that flame while being cooled by high speed airflow. $\endgroup$ Commented Feb 24, 2019 at 0:40
  • $\begingroup$ Yeah maybe they would be fine but maybe they wouldn't. There is (sadly) not really any way to know for us. But if they would have ejected they would still have to go thou the deadly debris cloud and thou the deadly hypergolic fuel. And during testing the hatch didn't open for I think 3 times. $\endgroup$ Commented Feb 24, 2019 at 10:20

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