 In one of the last episodes of the series ("Wild Journey"), Steve  and Dan travel back through space and time to before they left  Earth, and they attempt to change history by persuading any one of  their passengers not to take the fateful flight. Actor  Stefan Arngrim (qv), who played Barry Lockridge, had entered  puberty and could not reprise his younger self, so a body double  (with face obscured) was used.