This aerospace plant on the edge of a gravel pit in Azusa is owned by Northrop Grumman, and was operated under its Space Systems division for decades. It started as an Aerojet rocket plant during World War II, and after the war the company supplied motors for rockets used to launch NASA missions, and ICBMs. The majority of production was moved to Rancho Cordova, near Sacramento, and the Azusa site transitioned deeper into R&D, optics, and infrared detectors for satellite-based projects. Other related companies have operated in the office park, along Optical Drive, such as PerkinElmer, a supplier of sophisticated imaging systems for surveillance satellites. Northrop Grumman acquired the Aerojet facilities here in 2001.