Notably, both were hardware failures. Challenger blew up on launch because of a booster failure due to a faulty O-ring seal. Columbia burned up on re-entry be

Notably, both were hardware failures. Challenger blew up on launch because of a booster failure due to a faulty O-ring seal. Columbia burned up on re-entry because a piece of insulating foam broke off from the external tank during launch, damaging the heat tiles on its left wing. See also: https://en.wikipedia.org/wiki/List_of_spaceflight-related_accidents_and_incidents https://en.wikipedia.org/wiki/List_of_spaceflight-related_ac...