"The AB Chrysalis" is the twelfth episode of the second series of Space: 1999 (and the thirty-sixth overall episode of the programme). The screenplay was written by Tony Barwick; the director was Val Guest. Story It is 1,288 days after leaving Earth orbit, and in Command Centre, Koenig and the other Alphans nervously listen to a countdown from Fraser, followed by an explosion on the view screen. A shock wave is headed for Alpha, so Koenig declares red alert and orders all the Eagles to take shelter, in space, on the opposite side of the moon. After the shockwave hits, Alan Carter loses contact with Command Centre, and returns with all Eagles to find some fires, damage, and minor injuries, but an otherwise intact Moonbase Alpha. Helena Russell, dictating her log, explains that Alpha has been repeatedly subjected to explosions that recur every twelve hours. "As we move closer, each succeeding shock wave is more violent." The eye of the explosion is a planet, but the shock waves are traveling only toward the moon, and not damaging the planet. The theory: an intelligence is warning the Alphans to stay away. Koenig, Alan, and Maya launch Eagle 1 to investigate. As they approach the planet, they determine it has a chlorine-gas atmosphere and that it is surrounded by several moons that form a near-perfect circle around the planet. Landing on the nearest moon, they discover no evidence of life via the sensors, but do discover a collection of balloon-shaped buildings, the source of an unnaturally high level of energy. Koenig suits up to attempt to enter one of the buildings, and soon finds himself in an elevator that deposits him in a rock-walled cavern housing several globes perched atop stands. The globes and stands resemble the exterior buildings on the moons surface. Koenig is knocked unconscious by some sort of energy ray when he approaches one of the globes. Koenig recovers, and he and Alan watch as one of the globes dislodges itself from its perch and bounces to another of the stands in the room, then another. Koenig realizes it is "some kind of probe" and eventually, is proven correct when the ball begins to communicate. Geometric figures display on a view screen, and Koenig draws a triangle to demonstrate he understands the method of communication. After the view screen prompts them to diagram their place or origin, text appears