This is the processor unit of the CDC 3800, a computer that was used at the Consolidated Space Test Center in Sunnyvale, California, to operate Air Force satellites from the 1960s through the early 1990s.
The CDC 3800 was a large mainframe computer optimized for handling problems that required a lot of numeric processing. Control Data Corporation of Minneapolis-St. Paul introduced the 3800 in the early 1960s. The 48-bit computer used discrete transistors for logic, had a memory of 128 kilobytes, and had a 48-bit word length. A full system cost about $1.9 million.
This object is on display in James S. McDonnell Space Hangar at the Steven F. Udvar-Hazy Center in Chantilly, VA.