"The Testament of Arkadia" is the twenty-third episode of the first series of Space: 1999. The screenplay was written by Johnny Byrne; the director was David Tomblin. The final shooting script is dated 5 February 1975, with a revised final shooting script dated 25 February 1975. Live-action filming took place Tuesday 11 February 1975 through Tuesday 25 February 1975. Story Late into the simulated Alpha 'night', John Koenig sits alone in his office, updating the official log. As he reviews the past several days, the viewer can hear his thoughts courtesy of a voice-over narration. He reflects on how their struggle to survive in a hostile universe had long erased casual recollection of the cataclysm that hurled the Moon out of Earth orbit; however, recent events on the planet Arkadia have revived this painful memory, as the Alphans were forced to reconsider their purpose in space. The Commander's solemn words lead into an extended flashback... Days earlier, an off-duty Koenig is in the gymnasium when an urgent summons to Main Mission interrupts his Kendo work-out with resident martial-arts enthusiast Luke Ferro. The Moon has suddenly and inexplicably changed course; it is now heading directly for a solar system containing what may be habitable planet. Long-range scanners are activated—and immediately malfunction; a sudden five-percent power loss is the cause of the failure. The next minute, all personnel are hurled forward by a colossal lurch. Incredibly, their forward motion is slowing. Once in range of the planet, the Moon comes to a dead stop... At an emergency meeting, Victor Bergman muses that, while gravity or magnetic forces could alter the Moon's speed or trajectory, neither could completely halt its progress. Koenig is certain a third force, emanating from the planet, is responsible. Reports come in on the mounting power loss: diagnostics of the generators reveal no faults, but the energy output continues to drop. To Koenig's frustration, Computer identifies the cause as 'external forces'. If this trend continues, Moonbase Alpha will suffer a complete power failure in thirty-eight hours; a programme of power-conserving economies may provide an additional ten hours. Their only chance for survival may be the planet. With forty-eight hours of life-support remaining, Koenig quickly organises a survey mission. The team will consists of himself, Bergman, Helena Russell, Alan Carter, two Security guards and two mission specialists to be selected by Computer. These individuals will be chosen for having the