Set in the years 2062/63 the series features the missions of spaceship Fireball XL5, commanded by Colonel Steve Zodiac of the World Space Patrol. Also aboard as part of the crew were the glamorous Doctor Venus, middle-aged navigator and engineer Professor Matthew Matic, and Zodiac's co-pilot Robert the Robot, notable for being transparent. Robert was also unique as the only character in an Anderson series that was actually voiced by Gerry Anderson himself, albeit with the aid of an artificial larynx.
Fireball XL5 is based at Space City, located on an unnamed island in the South Pacific, headquarters of the World Space Patrol headed by Commander Zero. Zero is assisted by Lieutenant Ninety (whose name was later to inspire the name of another Anderson character, Joe 90). For some unspecified reason the headquarters is based in a 25 story rotating T-shaped control tower; in one episode the alien creature Zoonie the Lazoon inadvertently makes it rotate fast enough for those inside to suffer from vertigo. The patrol rocket Fireball XL5 takes off from a mile-long launch rail which culminates a 40 degree incline, or sky ramp, which Anderson claims was inspired by an old Soviet design, a concept also used in the film When Worlds Collide.
There is a fleet of at least 30 'XL' ships (an XL30 is referred to The Firefighters), of which XL5 is the most famous . The ship itself has two detachable sections. The winged nose section, known as Fireball Junior contained the cockpit and would separate from the main body to land on planets. The rest of the ship contained a laboratory, fuel, and even small rockets for interplanetary journeys, but generally would keep station in orbit. Fireball XL5 returned to Space City intact.
Inasmuch as the series used many classic early 20th-century science fiction tropes reminiscent of the space opera of E. E. 'Doc' Smith and the like, and since it was a children's show, it was not intended to be realistic. Thus Fireball XL5 managed to travel handily around the galaxy and to other solar systems without actually going faster than light (until the episode Faster than Light); indeed, few of the limitations of rocketry were observed. While some fans speculated that Fireball XL5 must travel through hyperspace (i.e. folded space-time), no such thing was ever mentioned on the series itself. Furthermore the crew never wore space suits –instead they took 'oxygen pills' to survive in the vacuum of space, where they maneuvered in zero gravity with the aid of thruster packs or jet mobiles.
Fireball XL5 was noteworthy as the only Anderson series run on a U.S. network. NBC (the National Broadcasting Company) ran the series in its Saturday morning children's block from 1963 through September, 1965.
Be sure to download the .AVI to get a 360 degree look at the ship.