The Challenger space shuttle disaster was 38 years ago today

January 28, 1986:
https://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster

The cold weather that day was part of what led to the disaster.

https://www.accuweather.com/en/weather-news/accuweather-founder-dr-joel-myers-reflects-on-weathers-role-in-the-challenger-disaster-in-his-new-book/1615962

It appears that the best "informed" guess as to how long they were alive and conscious was 6-15 seconds. Several did turn on their personal oxygen systems but with luck they were unconscious seconds after even though alive until they hit the ocean.

The remains of the astronauts weren't discovered until six weeks or so later.