The ADS fires a 95-gigahertz microwave beam, which is supposed to heat skin and to cause pain but no physical damage (New Scientist, 27 October 2001, p 26). Little information about its effects has been released, but details of tests in 2003 and 2004 were revealed after Edward Hammond, director of the US Sunshine Project - an organisation campaigning against the use of biological and non-lethal weapons - requested them under the Freedom of Information Act.

The experimenters banned glasses and contact lenses to prevent possible eye damage to the subjects, and in the second and third tests removed any metallic objects such as coins and keys to stop hot spots being created on the skin. They also checked the volunteers' clothes for certain seams, buttons and zips which might also cause hot spots.

One person suffered a burn in a previous test when the beam was accidentally used on the wrong power setting