Steve Bales is a former NASA engineer and flight controller. He is best known for his role during the Apollo 11 lunar landing.
At NASA he was assigned to work in the Flight Dynamics branch as a guidance officer, a flight controller responsible for determining the location of the spacecraft in space and monitoring the guidance systems on board. He was a backup controller for Gemini 3 and Gemini 4 but worked his first mission as a flight controller on Gemini 10 when he was still only twenty-three.
Steve Bales is best known for having been guidance officer (or GUIDO) during the Apollo 11 lunar landing when he had had the responsibility of dealing with several problems that could have ended the mission. While monitoring the lunar module's position and velocity he came close to calling an abort when it became clear a navigational error had occurred.