This container held the inflatable crew emergency egress slide. If necessary, a Space Shuttle crew would activate the slide by raising this container from its stowed position below the side hatch onto the frame of the open hatch and then pulling a lanyard to inflate the slide for a safe, quick exit to the ground.
NASA added crew escape equipment to all orbiters after the 1986 Challenger tragedy. This equipment was removed from Discovery after its final mission (STS-133 in 2011) and delivered to the Museum in 2012 after the inflation device was discharged for safety. The empty stowage container was reinstalled in the orbiter below the crew hatch, and the slide is in storage.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.