Dr. David Caulder (6 episodes, 1973)
Dr. Michel Lebrun (6 episodes, 1973)
Dr. Helen Smith (6 episodes, 1973)
Tom Hill (6 episodes, 1973)
Technician (2 episodes, 1973)
Ingrid (4 episodes, 1973)
Rao (3 episodes, 1973)
Bruno Ponti / Bruno Bertoli (3 episodes, 1973)
Director General (3 episodes, 1973)
Dr. Peter Conway (2 episodes, 1973)
Dr. Stephen Partness (2 episodes, 1973)
Walters (2 episodes, 1973)
Juan Benavente (2 episodes, 1973)
Sandy (2 episodes, 1973)
Lisa (2 episodes, 1973)
Cmdr. Bill Jackson (2 episodes, 1973)
Jenny (2 episodes, 1973)
Franz Hauser (2 episodes, 1973)
Prof. Heinz Laubenthal (1 episode, 1973)
Per Bengtson (1 episode, 1973)
Sir Benjamin Dyce (1 episode, 1973)
General Alexis Trenkin (1 episode, 1973)
Adam Blaney (1 episode, 1973)
Dr. Tony Ransome (1 episode, 1973)
Prof. Kate Weyman (1 episode, 1973)
Colonel Dimitri Gararov (1 episode, 1973)
Harry Sanders (1 episode, 1973)
Paula Renner (1 episode, 1973)
Bill Knight (1 episode, 1973)
Dodi Knight (1 episode, 1973)
Disc Jockey (1 episode, 1973)
Gregor Semyonov (1 episode, 1973)
Guido Mirandelli (1 episode, 1973)
Jane (1 episode, 1973)
Quiz Master (1 episode, 1973)
Mather (1 episode, 1973)
Mr. Edward Hopkirk (1 episode, 1973)
Astronaut (1 episode, 1973)
Dr. Andrew Robertson (1 episode, 1973)
Macadam (1 episode, 1973)
José (1 episode, 1973)
Gen. Cheng (1 episode, 1973)
Madame Carnac (1 episode, 1973)
Foreman (1 episode, 1973)
Technician (uncredited) (6 episodes, 1973)
Technician (uncredited) (5 episodes, 1973)
Moonbase Personnel / Technician (uncredited) (3 episodes, 1973)
Technician (uncredited) (3 episodes, 1973)
Technician (uncredited) (2 episodes, 1973)
Technician (uncredited) (1 episode, 1973)