Every reentry burn of the left OMS engine—used for the deorbit sequence—carried a small but non-zero chance of catastrophic failure. They performed the deorbit burn with the right OMS only, a contingency never before flown. Endeavour landed safely at Kennedy Space Center on August 21, 2007. Post-flight inspection showed the crack had grown by 0.05 inches—just enough to confirm the models were right, but not enough to fail. The tile repair held.
The crack was traced to a manufacturing defect: a titanium weld that had cooled too quickly in 1989, creating a microscopic martensitic phase inclusion. That tiny inclusion cycled through 18 flights (STS-118 was Endeavour’s 20th mission) before finally propagating. The 2007 crack is a haunting case study in risk management. Unlike the dramatic foam strike of Columbia , this was a quiet, cumulative failure—a slow betrayal by metallurgy. It revealed that even after the most rigorous post-Columbia redesigns, the Shuttle remained a fragile, aging machine held together by inspection intervals and statistical margins. Space Shuttle Mission 2007 Crack
Additionally, the tile gouge was repaired in orbit using a spacewalk-applied "goo" (a high-temperature filler called STA-54) and a mechanical plug. This was the first-ever on-orbit tile repair in Shuttle history. For the astronauts, the crack was an invisible enemy. Commander Kelly later wrote that knowing about the crack “was like flying a plane with a crack in the windshield—you can’t unsee it in your mind.” The crew had to trust ground analysis while looking at the very crack during spacewalks (the OMS pod is externally visible). Every reentry burn of the left OMS engine—used
In the end, the 2007 crack stayed small enough to ignore but large enough to remember. It was the sound of a program’s structural integrity quietly sighing under the weight of its own history. If by "Space Shuttle Mission 2007 Crack" you were referring to a different event—such as a crack in a window, a fuel line, or a simulation exercise—please provide more context, and I will refine the response accordingly. Post-flight inspection showed the crack had grown by 0