Dirección: Robert Parrish
Ambientada en el futuro. Tras el descubrimiento de un planeta gemelo a la Tierra que también forma parte del sistema solar, se decide enviar una nave espacial para investigarlo.
Roy Thinnes
Colonel Glenn Ross
Ian Hendry
John Kane
Patrick Wymark
Jason Webb
Lynn Loring
Sharon Ross
Loni von Friedl
Lisa Hartmann
Franco De Rosa
Paulo Landi
George Sewell
Mark Neuman
Ed Bishop
David Poulson
Philip Madoc
Dr. Pontini
Vladek Sheybal
Psychiatrist
George Mikell
Captain Ross
Herbert Lom
Doctor Hassler
Nicholas Courtney
Data Analyst
Peter van Dissel
Mallory
Jon Kelley
Nurse
Roy Thinnes
Colonel Glenn Ross
Ian Hendry
John Kane
Patrick Wymark
Jason Webb
Lynn Loring
Sharon Ross
Loni von Friedl
Lisa Hartmann
Franco De Rosa
Paulo Landi
George Sewell
Mark Neuman
Ed Bishop
David Poulson
Philip Madoc
Dr. Pontini
Vladek Sheybal
Psychiatrist
George Mikell
Captain Ross
Herbert Lom
Doctor Hassler
Nicholas Courtney
Data Analyst
Peter van Dissel
Mallory
Jon Kelley
Nurse
Roy Thinnes
Colonel Glenn Ross
Ian Hendry
John Kane
Patrick Wymark
Jason Webb
Lynn Loring
Sharon Ross
Loni von Friedl
Lisa Hartmann
Franco De Rosa
Paulo Landi
George Sewell
Mark Neuman
Ed Bishop
David Poulson
Philip Madoc
Dr. Pontini
Vladek Sheybal
Psychiatrist
George Mikell
Captain Ross
Herbert Lom
Doctor Hassler
Nicholas Courtney
Data Analyst
Peter van Dissel
Mallory
Jon Kelley
Nurse