The second flight after the Challenger crash came literally within inches of ending up the same way as Columbia's last mission, as a loose-foam impact dislodged

The second flight after the Challenger crash came literally within inches of ending up the same way as Columbia's last mission, as a loose-foam impact dislodged an insulating tile from the underside of the nose, which fortunately was at a point backed by a relatively thick steel mounting bracket for an antenna. https://spaceflightnow.com/shuttle/sts119/090327sts27/ https://spaceflightnow.com/shuttle/sts119/090327sts27/ As with the final Columbia mission, attempts to study the damage were thwarted (though in this case on specious security grounds, as this was a military mission.)