While on route to Space Station 9, Steve loses control of XL5. Racing out of control, XL5 passes the light barrier resulting in the loss of all but an hours worth of oxygen.
Gerry Anderson
Robert the Robot (voice) (uncredited)
David Graham
Lieutenant Ninety (voice)
Sylvia Anderson
Doctor Venus (voice)
Paul Maxwell
Colonel Steve Zodiac (voice)
John Bluthal
Commander Wilbur Zero (voice)