The Spaceman and King Arthur

Astronaut Tom Trimble (Dennis Dugan) and his robot companion are unexpectedly hurled backward in time during a routine space flight... and end up prisoners at the Court of King Arthur in sixth-century England! Adding to Tom's plight is his discovery of a sinister plot to overthrow the King, with the outcome resting on the flash-and-dazzle of the equipment at hand -- from the 20th century! (official distributor synopsis)