The space shuttle engineers found out that the internal nut had happened to slip out of position on Friday, September 10, 2010. This nut is used for the purpose of affixing the separation bolt to the belly of the orbiter.
A news report on September 10, 2010, stated: “A NASA spokesman said the problem occurred as engineers were attaching the left-side main separation bolt, part of the system used to ensure the shuttle separates from its external tank after reaching orbit”.
Following this discovery, the engineers were busy trying to re-position the wayward nut in the shuttle Discovery's aft engine compartment. They reportedly were finished with the bolting of the orbiter to its external fuel tank by Saturday.
Initially there were potential fears that they would now have to remove Discovery from the tank and then place it back in a horizontal orientation to make the necessary renovations. However, they then released that this could be done without the Discovery taking off.
On Thursday, Discovery was reportedly pulled from the processing hangar and dragged to the Vehicle Assembly Building. Then later in the day, a big sling was attached to the orbiter. The shuttle was then made to rotate vertically and then was raised up to a high bay.