The Atomic Weapons Research Establishment had a base on the site, used for environmental testing. When a laboratory test is conducted to determine the functional performance of a component or system under conditions that simulate the real environment in which the component or system is expected to operate. Many of the buildings from this time remain clearly visible from the quay at Orford, including the distinctive "pagodas". Whilst it is maintained that no fissile material was tested on the site, the very high explosive initiator charge was present and the buildings were designed to absorb any accidental explosion, allowing gases and other material to vent and dissipate in a directed or contained manner. In the event of a larger accident, the roofs were designed to collapse onto the building, sealing it with a lid of concrete.
In the late 1960s an experimental Anglo-American military over-the-horizon radar known as Cobra Mist was built on the peninsula. It closed in 1973, and in the late 1970s and early 1980s the site and building were re-used for the Orfordness transmitting station. This powerful mediumwave radio station - originally owned and run by the Foreign Office, then the BBC and, after privatization in the 1990s, a series of private companies - was best known for transmitting the BBC World Service in English around the clock to continental Europe on 648 kHz from September 1982 until March 2011. The station has been disused since May 2012.