Spacelab was a reusable laboratory carried in the Space Shuttle's cargo bay, providing lab space for astronauts and experiments. As a European project, it used a French-built Mitra 125 MS minicomputer instead of the Shuttle's IBM AP-101 systems. For storage, the Spacelab computer contained 128 kilobytes of RAM using magnetic core memory, where each bit was stored in a tiny ferrite ring.

The laboratory held three identical Mitra computers: one managed Spacelab, another managed experiments, and the third provided backup. The core memory stack took up roughly a third of the computer and consisted of seven boards: a driver board, four core plane boards, a second driver board, and an interface board. Each board had two 160-pin connectors linking to daughter boards for extensive connectivity.

Core memory worked by magnetizing toroidal cores clockwise or counterclockwise to store bits via current through wires threaded through the cores. Early computers faced storage challenges using mercury delay lines, CRT spots, or magnetic drums, but core memory offered dense, inexpensive, fast, reliable, and random access storage. Key inventors included Jay Forrester at MIT, who developed practical core memory for the Whirlwind computer in 153, along with Frederick Viehe, An Wang, and Jan Rajchman, whose patents led to major IBM settlements.