A design flaw (foam) under launch stress resulted in foam shedding and leading edge wing impacts damaging tiles and ensuring loss of the vehicle on reentry.
I'd argue the failure was in design, triggered during launch, and manifested on reentry. But Columbia was doomed from seconds into flight.
The Falcon only has to solve the problem of getting the payload into orbit. The Shuttle had to both get payload into orbit and return its crew (and the Orbiter, and any return payload) safely to Earth (the Dragon capsule has to do this as well but the statistics given are for all Falcon launches). So as far as comparing the technical challenges involved with Falcon vs. the Shuttle, the Shuttle was solving a harder problem, which I think makes the numbers for the Shuttle look even better relative to the Falcon.
Harder at least as in there are extra steps that can go wrong (re-entry + landing), I suppose it’s debatable which was really a more difficult engineering project…
A design flaw (foam) under launch stress resulted in foam shedding and leading edge wing impacts damaging tiles and ensuring loss of the vehicle on reentry.
I'd argue the failure was in design, triggered during launch, and manifested on reentry. But Columbia was doomed from seconds into flight.