Thanks to Thomas and others
Outside the Eagle door we see a distinctive cone shaped rock. We see the Alphans walk past this rock, the tree and the rock wall behind it a couple of times before they finally look at it again, see the glow coming from the cave, and Reilly says "Hello, hello, hello."
Through the cave is the rock. As this wide shot shows, it's exactly the same set as above. The distinctive conical rock is the same, as is the rock face behind. The white tree has been replaced by the glowing rock.
This is the other side of the planet surface set. The rock wall and conical rock are on the left (seen for instance when the Eagle is taking off). The backdrop, with sky, mountains and white trees, is obviously a painting in many of the shots. The white tree prop is seen in different positions.
Reilly scans the rock and realises it's not milgonite. His stun gun is only loosely holstered, and the actor strikes the pistol accidentally with the scanner. The stun gun is knocked further out of the holster. As he walks around the rock towards the Commander we lose sight of the gun, but a loud thud is heard as the prop hits the sound stage floor. We can briefly see the empty holster as he turns. Thanks to John Day.
When Helena pronounces Tony dead, her hair is slightly out of place. We see the reactions of the others, then a group shot, which reveals that Helena's hair is suddenly very dishevelled. When we return after the commercial break, Helena has evidently tidied her hair. Thanks to Michael Thompson.
When Tony first walks out the Eagle, they search extensively for him. He must have taken the direct route between the rock and the Eagle and back again, which seems the obvious place to start looking.
Apparently only Tony's commlock can open the Eagle door (Koenig states "If we can take Tony's commlock, we can open that Eagle door."). Yet when he returns with the first piece of rock, he is carrying it with both hands and could not operate his commlock. Later when Reilly returns to the Eagle, he carries the Maya/rock in both hands but also holds Tony's commlock.
The position of Tony's commlock changes while he is unconscious. Shortly before the Eagle takes off, it has disappeared.
When Koenig and Alan meet Maya and Dave to tell him his source was wrong, Alan's hands are visible ; in the next shot, they are in his pockets. All the characters are closer to one another than in the previous shot.
The green light passes over the Alphan boxes. One of them has a name on- "Tom Bowen", the character played by Brian Blessed in The Day After Tomorrow. These are the bags that the Altares crew take on their ship at the start.
These cases are LP record cases. In the 1970s most of these were black vinyl, so it is possible they were painted silver for the show. Thanks to Richard Totis.
The light passes over the boxes, and finds the water. The first time it scans the boxes, the water can is not there (there is even a close-up as it passes where the water will appear). It only appears when the light beam finds it. The hexagonal box behind change numbers. Number 3, has a black number on white in most shots, but a white number on black when the water cans are present. The box below it has a white on black "4" - or a black on yellow "9". On the right, the top box is white on red "8" in both versions, but below is black on white "1" - or no number at all. When the light beam is searching, the orange Hampa Pak picnic trays disappear. When they are alongside the water cans, they have turned around, so the black straps are on the outside.
As the Eagle rises and descends, Koenig, Alan and Reilly grimace, but Catherine Schell seems to be laughing - she turns her head and use her arm to hide it.
When Tony stands, after the Eagle launch, he suddenly has a stun gun in his hand and the commlock in the other. It would have been a sensible precaution to remove his stun gun, especially after his first excursion.
The laser rifle is only present when Helena is trapped against the wall- at other times it has gone.
Tony blasts away a piece of the rock. The explosion casts a strong shadow of the rock wall and the rock cone against the painted backdrop.
When Reilly takes Tony's commlock, the long shot shows he is some distance from the commlock. The close up shows him taking it within easy reach. Note the medium shot of his head shows Maya has changed position.
Space 1999 copyright ITV Studios Global Entertainment. Page copyright Martin Willey