Spacelab

This double exposure image shows Spacelab-1 in the cargo bay of orbiter Columbia. From top to bottom inside the cargo bay are the Spacelab Access Turnel, which is connected to the mid-deck of the orbiter; the Spacelab module, a pressurized module in which scientists conduct experiments not possible on Earth; and Spacelab pallets, which can hold instruments for the experiments requiring direct exposure to space.