Goofs

In Helena's opening narration, she gives Alpha's population as 297. However, assuming there were no casualties within Moonbase Alpha when the moon initially broke away, there were 20 deaths on Breakaway (1975) alone, none of which the newscaster had been aware of (12 from the "disease" - which had been kept secret - and eight pilots at Nuclear Disposal Area Two). Afterwards, during the first season, at least 41 Alphans died (not counting the presumed off-screen death of Victor Bergman), three left (Simmonds, Anna Davis, and Luke Ferro), and one baby (Jackie Crawford) was born. Alpha's population should be no more than 248 by this episode's start.

The Alpha computer misspells manganese trisilicate.

John Hug (Fraser) acts stunned just before the (postproduction) laser beam is shown actually hitting him. The optics came in a little late (reportedly, the opticals were so time-consuming since they were done off-site by another company that it was out of the question to ever be sent back and redone).

While the landing party is traversing the underground tunnels, Maya arrives at the Grove of Psyche. Catherine Schell almost trips moving through the circular doorway.

When the robot Eagle lifts off to head to the planet, Tony states "In 10 minutes, it will be all over". Even if the moon had been in Psychon's orbit (which it wasn't), it's doubtful the trip would only take 10 minutes.

Though very Eurocentric in the previous season, all wall signage and viewscreens in the second uses the US-style Command Center - apart from the station where Annette Fraser monitors Eagle One, uniquely labeled Command Centre computer. Tony's and Sandra's ID badges also use the UK spelling.

Immediately after being created, Mentor's spaceship rises from the surface and a star in the background shown through Psychon's atmosphere seems to go right through the ship as its rising, as though the ship were transparent. The same phenomenon occurs a little later; a star seems to pass right through Eagle Four as its booster units have enabled the ship to break free of the alien craft's tractor-beam-like force.

After one Eagle is earlier captured, Helena tells John to look out of their Eagle window at the "spaceship graveyard" that they have been pulled into - but the camera view isn't out of the Eagle window but of the entire graveyard since two Eagles are shown. (Note: the viewer is shown the whole layout of the volcano floor, but it's not the same view the Alphans are seeing. They're observing their own view screen, which isn't seen by the audience).

The color-coded sleeves on the Alpha uniforms on this season are inconsistent with the previous year. In this episode, Torens - a pilot - wears yellow instead of orange and Bill Fraser always appears in red throughout this season.

In the final scenes of the Grove of Psyche, gas pipes are visible across the floor for the fires.

It was out of character (particularly Alan and Dr. Russell) for the landing party to fail to suspect that Commander Koenig was up to something when he ordered the base evacuated to the planet, hastily concluding that Koenig was "selling out". They had seen him act similarly "irrational" on the previous episode The Last Enemy (1976).

Poor old "red shirt" Torens - Koenig doesn't ask about him being missing when Helena and Fraser race back to the fleeing Eagle without him (unless it was mentioned during a deleted scene - there seems to be 13 seconds missing from the climactic escape in the Eagle from the exploding Psychon, right before Eagle Four lifts off).