The Catacombs The Continuity Guide
Moonbase Guide
Power and Life Support
by Martin Willey

Main Power Unit


The power core. Compare to the similar unit in Life Support.

The Main Power Unit, seen in Black Sun and Earthbound, oversees the four nuclear generating areas. In the latter episode it is slightly different (here it is named as the "Nuclear Power Station" in Maintenance Section). It is also referred to in Ring Around The Moon. The "Main Power Plant" is mentioned in Seed Of Destruction.

The Power Unit has a large staff (about five plus 1 security guard internally and two more externally). In Year 2 it seems to have been replaced by Life Support, which is more automated and thus usually unmanned.

The text on the panel in Earthbound is "Converter Main Unit" (it's nearly illegible in the countdown typeface). Inside, alongside "Danger" and "Do Not Open" signs, a label reads "Nuclear Energy Converter". Actually there are two panels, so presumably there are two units. In the panel we see, there are three cylinders, only one of which Simmonds removes.

The Main Unit panel is also seen in the Eagle Hangar Control Room in Space Warp (minus the large "Danger" sign but still with the "Do Not Open" smaller sign.

The room is actually a revamp of the Command Office (plan). While that set had 3 windows, this has 4. The Black Sun scenes were filmed on 19th February 1974, the Earthbound scenes were filmed on 18th March 1974.

Entrance: Security Area

Earthbound Earthbound Earthbound

Doors and consoles

Earthbound Earthbound Earthbound Black Sun Black Sun

Forcefield controls

Under the screens are 8 panels, one for each forcefield tower; Bergman opens up panel 7.

Black Sun Black Sun

Converter Main Unit

Earthbound Earthbound Earthbound Earthbound Earthbound Earthbound Earthbound

In this shot we can see just beyond the left corner of the set (seen below the communications post). The corner blocks are missing from the end of the desks. Simmonds should be talking to the communications post, not empty seats in the block of desks.


The layout is based on the Command Office, but with 4 windows (instead of 3), and a little narrower (the double doors sit inside the big doors to Main Mission). All 6 Main Mission desks, and the 4 corner units, have been moved into a block in the centre.

Between Black Sun and Earthbound, the wall by the communications post changes, removing the panel hatches that electrocute Bergman, replaced by the "Converter Main Unit" panels which Simmonds forces open. The communications post itself moves (in Earthbound it is where the Moonbase Alpha model was in Black Sun). The individual computer panels are also different (this plan follows Earthbound, as we see them more clearly).

We only see 2 end panels of the left wall by the windows; the rest is hypothetical based on the Command Office layout.

Black Sun Wall

Earthbound Wall
Wall Plan Wall

Copyright Martin Willey