The Apollo Lunar Surface Experiment Package (ALSEP) was a collection of scientific instruments stowed on a pallet during transport to the lunar surface. During their first moon walk (EVA), the astronauts deployed the instruments on the lunar surface. Each experiment was electrically connected to the Central Station of the ALSEP. An antenna on the Central Station allowed communication with Earth.

This particular artifact, Subpackage 2, is a set of components and experiments stowed together on the ALSEP pallet. The rectangular components along the front are parts of the Heat Flow Experiment. The circular finned object in the back is the Radioisotope Thermal Generator (RTG), the power source which provided 70 Watts for use by all of the ALSEP experiments. The item next to the RTG is the Passive Experiment Stool. The ALSEP experiments varied for each Apollo mission. This particular assembly was used for Earth-based training in EVA procedures by Apollo 16 astronauts. It was transferred by NASA to the Museum in 1975.