Most dramatic genres – domestic drama, thriller, romance, song and dance, historical – exist equally on stage and screen. The exception is sci-fi, with just a few futuristic pieces for the theatre including Karel Capek’s 1920 play R.U.R., which invented the word “robot”, Alan Ayckbourn’s time-travel comedy Henceforward and the musical Return to the Forbidden Planet.

This small sub-set is now extended by X, a new play set in a research base on Pluto. The dramatist, Alistair McDowall, established himself with Pomona, a complex non-naturalistic thriller, and X is similarly slippery in chronology and content. At times, the writer seems to be combining a space play with a ghost story, as a bloody sign appears on a window and one of the galactic travellers has reported seeing a small child.