 The only connections between this series and the previous run were the name "P9", that of Mercator, and the Tope, the clear cubicle which formed a central part of the programme's set, played by Stephen Hope Wynne (who played numerous other characters in all the seasons), and which in this series switched from being a dimensional prison to become the space station's power source.During this series, a 'base station' (static caravan) was used to provide a 'link' by which guests could be 'transported' from Earth to P9