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