Launched in 196X and manned by Glenn and Fuji, the P-1 was an interstellar craft able to travel through space at ungodly speeds. The ship would give mankind first hand views of other planets and galaxies. It was in fact during one of the ships orbits around Earth, did the World Space Authority technicians began to receive strange radio waves. Emitting from a previously unknown planet on the blind side of Jupiter, the P-1 was set on mission to find the source of the disturbance. Setting their ship down on the unusually warm Planet X world, the pair of astronauts found an alien race named the Xilien. A group of beings that pleaded for their help in eliminating the being Monster Zero: King Ghidorah. The Xilien requested for the team of Godzilla and Rodan in order to ban the threat of the golden demon from their lives forever. With this request at hand, the astronauts returned to Earth in the P-1 to seek the council of the world's leaders.

Much later, after the requested had been fulfilled, Glenn, Fuji and doctor Sakurai found themselves as guests of Planet X. For their return voyage home, the Xilien had created a duplicate of the P-1. Its mission was to see Fuji, Glenn and Sakurai safely home along with the tape that supposedly contained the cure to all disease. The ship had minor justification's done to it in comparison to the P-1,such as the ability to carry an extra crew member in the cockpit. The Xilien's P-1 was successful in its mission of bringing Fuji, Glenn, and Sakurai back to Earth. However, the craft was later destroyed by the Xilien during there takeover.