Sunnyvale is a city in Santa Clara County, California, United States. It is one of the major cities that make up the Silicon Valley. As part of the Silicon Valley, Sunnyvale is headquarters to several high-tech companies such as Maxim Integrated Products, Juniper Networks, Palm, Inc., AMD, NetApp, Spansion, Yahoo!, Mirapoint, and Ariba. Sunnyvale is also home to several aerospace/defense companies; Lockheed Martin has a major facility in Sunnyvale, and Honeywell, Northrop Grumman Electronic Systems - Marine Systems (location of the Hendy Iron Works Museum), and Spirent Communications also have offices in Sunnyvale. Sunnyvale is also the home to Onizuka Air Force Station, where its main building, locally known as the Blue Cube, is its most prominent feature. The base, named for the deceased Space Shuttle Challenger astronaut Ellison Onizuka, is the primary artificial satellite control facility of the United States armed forces.Sunnyvale is one of the few U.S. cities to have a single unified Department of Public Safety, where all personnel are trained as firefighters, police officers, and EMTs, so they can respond to an emergency in any of the three roles.