Episode Guide

• Shooting script dated 12 April 1976. Revised 21, 26, 27, 28 April. Filmed 4 May-18 May 1976
• A "Double-Up Helena" script- while Bain and the other cast were filmed in the studio, Landau and Schell filmed The Rules Of Luton on location.
• Wrong credits: Raul Newney is credited as "Raul Newey".

• The Archanon ship was built by Martin Bower between the filming of the two series. A revamped version of the model appears in Space Warp.

• The virus (or genetic disease- the episode calls it both) is obviously based on haemophilia, a genetic disease caused by the absence of the gene for making the blood clotting protein Factor VIII. It is a hereditary disease passed only in males, treated by blood transfusions.
• In stasis the Archanons are standing. Standing requires muscular effort and brain coordination; humans cannot stand while asleep.
• The lunar caves are apparently natural (and are seen again in Catacombs Of The Moon; see more science notes there). It is an incredible coincidence that Moonbase Alpha is built over the former location of an alien base - but a well-developed system of lava tubes would be ideal for any lunar settlement. Evidence of laba tubes on the moon was first discovered in 2010.
• The Eagle is in a "meteor storm". Meteors are asteroids burning up in an atmosphere; the correct term is asteroid.
• Even in the recording from a thousand years ago the Archanons speak modern English

Alpha Technology:

• The laser cutter is called a sonarscope in the script. It is seen again in The Bringers Of Wonder part 2 and The Immunity Syndrome.
• Tony seems to use his torch as a scanner. It is used normally as a torch in Another Time Another Place, Testament Of Arkadia and Catacombs Of The Moon.
• The Alpha Log Recorder appears.
• In the Medical Centre, Helena uses a keyboard from Main Mission. Alongside it is the nuclear detonator from Space Brain (the radiation symbol is clearly visible).
• We see the only animals on the moon in this episode: doves.

• In the asteroid storm, the Eagle's legs are sometimes bent, sometimes not (for some shots the Eagle was filmed standing vertically so dust could be dropped past it; hence the bent foot pads). It also changes between the second and third Eagle model, with obvious differences in panel details.

• The football match alluded to is rugby league at Swinton in the UK on 9th November 1963 when Australia beat Britain 50-12.
• Was Crom II another planet that Alpha visited? (according to the script it was).
• The name Pasc indicates a Passover analogy, with Pasc spilling his blood to redeem his son.
• Cobber? Yeah. That means you're a pal, you know, a real close buddy. The Australian colloquialism is considered archaic and rarely used (the preferred colloquialism is "mate").
• Emma Porteous's description on her design for Maurna's lilac dress: Dress in pleated silk - ornamented at bodice with silk flowers - stitched and beaded in gold- hung with long scarlet cords - metal bracelets - hung with long scarlet fringe -.