"The Full Circle" is the fifteenth episode of the first season of Space: 1999. The screenplay was written by Jesse Lasky, Jnr and Pat Silver; the director was Bob Kellett. The final shooting script is dated 17 September 1974. Live-action filming took place Tuesday 24 September 1974 through Tuesday 8 October 1974. Story The Moon is passing within range of a habitable planet the Alpha staff have code-named 'Retha'—an anagram of 'Earth'. A six-man team is dispatched for a preliminary survey. After several hours, radio contact is lost and Eagle Six fails to return on schedule. Flight telemetry shows all ship's systems operating normally, and a worried John Koenig orders it flown back to Moonbase Alpha by remote control. He, Victor Bergman and Helena Russell go to meet the mystery vessel. They can find no one aboard...until Helena spies a primitive stone axe and a hairy hand nearly hidden behind a seat in the passenger module. A closer look reveals the sole occupant—the dead body of a Stone-Age man. While the bizarre corpse is taken to Medical for a post mortem, Koenig plans a rescue mission. He will lead a search party on the ground, while Alan Carter will overfly the area in Eagle Two in a search pattern centred on the initial landing site. Sandra Benes will accompany him to make a detailed photographic scan. Left in command of Alpha, Bergman watches the rescue ships depart. With just three days remaining before the Moon travels out of range, he admits the disappearances could seriously affect their chance of colonising Retha. Eagle One sets down at the first expedition's landing site, a clearing in a sub-tropical forest. As Carter begins the aerial search, he notes a few pockets of mist through breaks in the forest canopy, but no sign of people—Alphan or otherwise. While the support team reconnoitres the immediate area, Koenig and Helena drive off in a moon buggy, following a series of trail-markers left by the reconnaissance party. Entering the forest, they leave the vehicle and continue on foot. At a swampy watering hole, they are brought up short by the tracks of a gigantic animal. Helena perceives movement in the foliage on the far side of the pool and thinks they are being watched. Koenig fires a stun-gun blast into the water to frighten off who or what is in hiding. Hours later, the trail-markers lead them