A recent answer quoted the statistic that

over 10% of astronauts have died on the job

That got me wondering what the trend over time has been in mortality rate of astronauts, i.e. is space travel getting safer, or more dangerous, or staying about the same?

Ideally an answer would take the population at risk into account, e.g. recording both the year-by-year (or decade-by-decade) number of active astronauts as well as the number of fatalities (I guess this could also be quantified at the level of missions, which might make sense given that accidents would typically (??) kill the entire crew of a mission ...)

I've briefly searched for answers on this site and haven't found anything obvious. I can see that this Wikipedia page would give me the fatalities, but I'm not quite as sure where I would go for the denominator (number of active astronauts by time).

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    $\begingroup$ The info in the linked article is enough to plot this. But I don't know that it would be statistically valid. The profession is still so new and has such a small population, in a quickly changing industry, that I don't think any trends there might seem to be would be of any use in predicting the future. $\endgroup$
    – kim holder
    Commented Apr 16, 2021 at 20:39
  • $\begingroup$ @kimholder, I also think I'd need to know the number of missions per year? (Preferably I would do this at the individual-astronaut level but that actually gets a bit tricky statistically, separate from the issue of getting the data ...) And, I'm not that concerned about forecasting; would just like to describe ... $\endgroup$
    – Ben Bolker
    Commented Apr 16, 2021 at 20:54
  • $\begingroup$ Since the Wikipedia page lists lots of astronauts who died in training accidents rather than on missions, that would be a reason to try to do the analysis at the astronaut level ... $\endgroup$
    – Ben Bolker
    Commented Apr 16, 2021 at 20:57
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    $\begingroup$ Different question but related: Is the overall mortality rate for being in a spacecraft in space or bound for space about 4%? $\endgroup$
    – uhoh
    Commented Apr 16, 2021 at 21:04
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    $\begingroup$ The data is episodic and clustered (many incidents with multiple fatalities) that any conclusion may not be statistically valid. You can probably find a way to support any conclusion you wish. $\endgroup$
    – DrSheldon
    Commented Apr 16, 2021 at 21:08

1 Answer 1


According to Chris Hadfield, the first space shuttle launch in 1981 had a potential death rate of 1 in 9. By the time of his first launch in 1995, the odds had been reduced to 1 in 38.

I don't know what his source is, but given that he says 'now that we go back looking at the history of the space shuttle' and that he uses quite specific numbers, it's implied that he is referencing a risk study by NASA.

I haven't been able to find the actual study, but the same one is referred to in this article.



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