In this episode, the Russians launch a moon rocket to take out the Cyber control ship. On the date the episode was broadcast, Apollo 8 was launched and would become the first manned ship to orbit the moon.
When Vaughn zaps a Cyberman with the Cerebraton Mentor , it is a very obvious dummy that falls from the roof.
The Doctor's opening line ("Is this what you wanted, Vaughn? To be the ruler of a dead world?") is slightly different from the version on the cliffhanger to Episode 7. ("Is this what you wanted? To be the ruler of a dead world?")
The stock footage used for the missile launches is frequently repeated and combines footage of two different types of missile.
Zoe: No, exhausted.
Major Branwell [ of Zoe ]: Can't we keep her on, sir? She's much prettier than a computer.
Frazer Hines was on vacation for this episode and only appears in a pre-filmed insert.
Some of the UNIT extras were professional soldiers from the Coldstream Guards.
This episode bears an additional credit:
THE BBC WISH TO ACKNOWLEDGE THE HELP GIVEN TO THEM BY THE MINISTRY OF DEFENCE IN THE MAKING OF THIS PROGRAMME
Kevin Stoney, who plays Tobias Vaughn, would later return in another Cyberman story, Revenge of the Cybermen.