Patrick Troughton, who played the second Doctor in 'Doctor Who,' is the Dorcon leader that Maya's brainstem is going to be transplanted into.
During the fight with Koenig on the Moon's surface, Sanderson's spacesuit visor opens about an inch as he falls on his back.
As Alan drove a moon buggy around near the nuclear waste site, the '5' numbering on the sides and front were reversed in many shots.
On the medical monitor, Helena saw the Swift landed outside the Alpha nuclear waste site, but if she was still under the aliens' influence, she should have been seeing it in New York. Only Maya and Koenig should have seen the ship (actually an Eagle) at the waste site. Also, they say that the aliens have to be present to exert their control, yet none were in the room with Helena, Maya and Koenig, so she should have been able to see the Eagle.
In Part 1, Helena said it was 1912 days after the moon left Earth. In this episode, she says it is 2515 days, placing Part 2 almost 2 years after Part 1. In dialog, Koenig says, "We've been in space for months." The previously given figure would mean it's been almost seven years, not just months.
When Koenig crashed, his helmet was beside him. However, when rescued, he was wearing it.
The episode has no scenes set on Moonbase Alpha and no characters other than the six on the Eagle.
The Eagle featured in this episode was carrying an extra-wide laboratory pod, yet whenever the characters used the door from the standard pod interior, it leads immediately outside. Also, the door to the pod as used by the characters was the wide door of a standard pod rather than the narrower door shown on the model of the laboratory pod.
The rocks could teleport Tony from the cave to the Eagle, yet they didn't seem to be able to do this to themselves so they wouldn't need other lifeforms to carry them to water.
As Eagle 4 lifts off under the rock's control, one shot of it in mid air showed a standard Eagle, not the "specially adapted laboratory section" it has at all other times.
Goof: In the scene where Magus takes away Koenig's laser gun, a hand can be seen placing it into his hand where it has materialized.
After the Vega computer shuts down, the first human to unmask itself is numbered 16, but in the group shot immediately following in which Tony and Maya walk among the androids, 16 can be seen in the background still masked.
After being stunned in the Alpha power plant, Helena, Tony and Maya all change positions in later shots from where they originally fall.
Helena says they can't allow children to be born on Alpha as the strain on the life support systems would be too great, yet no one made any effort to prevent Jackie being born in "Alpha Child".
Cantar's stun is supposed to last an hour but when Tony is stunned he wakes up after only 30 seconds.
When we first see Maya enter into the chamber where her father is you can see that she trips slightly through the doorway. She seems to catch herself and keeps going.
Goof: When Koenig fires the boosters to get away from the magnetic ship, we are shown images of the crew's faces as if under high acceleration or G forces, even though they are hardly moving. But when the "ball of light" pulls them down much faster, there is no similar reaction on their faces.
Throughout this season, Tony Verdeshi is said to be Alpha's Chief of Security, yet he always wears a red uniform denoting the Main Mission section instead of purple for Security.
This is the second time Brian Blessed (Mentor) appeared as a guest star on 'Space: 1999'. His first appearence was in the episode 'Death's other Dominion' as Doctor Cabot Rowland.
Both Bergman and the Bethans state that because the two planets always have their star between them, they cannot directly shoot at each other. It is common practice today to slingshot space probes around celestial bodies, using their gravity to alter velocity and course, what's known as a "gravity assist" maneuver. A straight line course between planets is not necessary. That is, assuming their advanced missiles inexplicably had no guidance systems that could correct their course in mid-flight and they were just firing blindly.