NASA mission managers fell into the habit of accepting as normal some flaws in the shuttle system and tended to ignore or not recognize that these problems could foreshadow catastrophe. This was an “echo” of some root causes of the Challenger accident, the board said. —Shuttle [Columbia] Report Blames NASA Culture (MSNBC)

This suggestion comes from Tracy, a former technical writing student. She was in my class the day I had planned to introduce a book on the 1986 Challenger accident. That class was scheduled for 12 September 2001. Obviously, we had other things to talk about that day.