[queuebert]

What are the units on 1 in 75? People? Missions?

To compare with other launch methods, you'd need to use the same metric.

IIRC, Soyuz is actually more deadly, but it's been some time since I've seen the stats. Both Soyuz and the Space Shuttle are by far the most deadly form of transportation.

[midasuni]

Broadly the same - 7 seats a launch, about 2 failures in about 150 launches, or 14 seat failures in 1000 seat launches. The early launches didn’t have 7 people on but it’s not really relevant.

Worryingly for the shuttle the second failure was well into its lifespan. 5 failures in 50 launches then no failures for 200 more launches is better than 1 failure every 60 launches despite the second being theoretically better from the numbers.

[mathgeek]

You can either use 14/833 crew positions (individuals flew more than once), or 14/355 actual people who ever flew on the shuttle. You could also use 2/135 missions. I suppose an argument could be made for 2/269 as well if you want to count launch and reentry as separate risk events.

Source: https://www.space.com/12376-nasa-space-shuttle-program-facts...