Comment by jedc

Data points that worry me:

02/1967 - Apollo 1 fire

01/1986 - Challenger disaster (19 yrs later)

02/2003 - Columbia disaster (17 yrs later)

It's been 23 years since Columbia, and there seems to be a 20-ish year rhythm to NASA disasters where the organization learns lessons, becomes more careful... and then standards potentially slip.