Radar Tubes for Defense

The launch of Sputnik 1 in 1957 proved that Soviet missiles armed with nuclear weapons could reach the United States. In response, Americans established an integrated system of radar stations to detect missiles in flight. The Ballistic Missile Early Warning System included large stations in Alaska, Greenland, and England. The radar waves were generated by devices called klystron tubes. Though tubes are no longer used, the stations remain in operation today.

Klystron Tube, 1959
This klystron tube made by Varian Corporation operated for over three years in the Thule, Greenland, radar station. The tube emitted ultrahigh frequency waves around 425 megahertz. (Collected 1964, Gift of Varian Associates)

Ballistic Missile Early Warning Station, Clear, Alaska, 2001
(Courtesy of Library of Congress)

Children Taking Part in Take Cover Drill, 1962
(Courtesy of Getty Images)