Spacelab could be configured with an enclosed laboratory module, exposed platforms called pallets, or a module-pallet combination. The igloo canister was used on pallet-only missions. Mounted beside a pallet, it held subsystems that supplied power and other utilities to instruments and experiments on the pallet. Missions using an igloo included Spacelab 2, Astro-1, ATLAS-1, ATLAS-2, ATLAS-3, and Astro-2.
Two igloo units were manufactured by the Belgian firm SABCA, and both were used in space. This one has intact exterior thermal insulation, but its internal hardware has been removed for reuse. NASA transferred it to the Museum when the Spacelab program ended in 1999.