Commander Stevenson was the head officer of the Nerva Beacon crew.
Stevenson, Lester and Kellman were the last survivors of the plague affecting the station. The Cybermen forced him to carry Cyber-bombs deep inside Voga along with the Fourth Doctor and Lester. The Doctor managed to deactivate the bombs and they met up with the Vogans. Stevenson used the controls there to redirect Skystriker in the cyber-ship, destroying it. (TV: Revenge of the Cybermen)
