This is the only Hammer film set in the future.
The film's lunar surface sets and models were so well done some were re-used in other television productions for many years afterwards, appearing in the likes of UFO (1970), Moonbase 3 (1973) and Space: 1999 (1975), as well as the feature films Superman II (1980), Superman IV: The Quest for Peace (1987) and as recently as Duncan Jones' debut film Moon (2009).
The film was described by the producers and director as a "Western in space" complete with claim jumpers, showdown-type gunfights, a hired gunslinger and even dancing saloon girls.
Actor and dancer Yvonne Castelle was paralyzed for life after an accident on the film's set, remaining bedridden for 10 years.
The film takes place in May 2021.