dscc9721.jpg

At the base of gusset #2 is an unusual and modern-looking fixture (these are present at the base of all four gussets). It appears that the Smithsonian has inserted a threaded rod and some sort of lifting lug in the bolt hole for the launch escape tower.

They are presumably to assist in transporting Columbia for the tour. They were not present when she was displayed in the Milestones of Flight gallery.