Apollo Portable Life Support System (PLSS)

The "backpack" worn by Apollo crewmen while performing extravehicular activities was called the "Portable Life Support System" or PLSS.

The PLSS was a compact assembly of various environmental control devices which supplied breathing oxygen; controlled suit pressure; recirculated oxygen after removing CO₂, odors, moisture, and trace contaminant gases; controlled temperature; provided warnings of certain system malfunctions; and provided voice communications and data telemetry. The PLSS, along with the suit itself, essentially formed a wearable spaceship for the astronaut.

The interior components of the PLSS were protected by a hardcover which was then wrapped in layers of Betacloth, making it look rather plain and ordinary, but the PLSS was a complex device.

The museum displayed the PLSS near the center of a large display, preventing me from getting very close to it or taking more detailed photos.