Guest Stars Derek Ware as Unit Sergeant James Clayton as Private Parker John Lord as Masters Derek Ware as Astronaut Max Faulkner as Unit Soldier Roy Scammell as Technician Robert Cawdron as Taltalian William Dysart as Reegan Ronald Allen as Ralph Cornish Ric Felgate as Van Lyden Cheryl Molineaux as Miss Rutherford Michael Wisher as John Wakefield Tony Harwood as Flynn Juan Moreno as Dobson James Haswell as Corporal Champion Carl Conway as Control Room Assistant Joanna Ross as Control Room Assistant Bernard Martin as Control Room Assistant Geoffrey Beevers as Private Johnson Ric Felgate as Astronaut Neville Simons as Michaels Neville Simons as Astronaut Steve Peters as Lefee Steve Peters as Astronaut Peter Noel Cook as Alien Space Captain Robert Robertson as Collinson Gordon Sterne as Heldorf Dallas Cavell as Quinlan Ray Armstrong as Grey Peter Halliday as Alien Voices Cyril Shaps as Lennox John Abineri as Carrington
