Fireball XL5

• Colonel Steve Zodiac (voiced by Paul Maxwell): the pilot and commanding officer of Fireball XL5. In the episode "Space City Special" he is declared "Astronaut of the Year".
• Doctor Venus (voiced by Sylvia Anderson): a doctor of space medicine, of French origin. Zodiac personally selected her to be a member of the XL5 crew. According to the episode "The Last of the Zanadus", Venus has served five years on the ship.
• Professor Matthew "Matt" Matic (voiced by David Graham): XL5's engineer, navigator and science officer.
• Robert the Robot (voiced by an uncredited Gerry Anderson using an artificial larynx): the co-pilot of XL5, a transparent robot invented by Professor Matic and Earth's most advanced mechanical man.
• Zoonie the Lazoon (voiced by David Graham): Venus' lazy, semi-telepathic pet from planet Colevio. During his early appearances, he can say no more than "welcome home". His vocabulary expands as the series progresses, often due to him mimicking other characters.
• Commander Wilbur Zero (voiced by John Bluthal): the operational commander-in-chief of the World Space Patrol and chief controller of Space City. Despite his gruff exterior, he cares deeply for his subordinates and respects them, especially Steve. Zero's rank appears to be above that of Colonel but below that of Space General.
• Lieutenant Ninety (voiced by David Graham): the assistant Space City Controller. He is young, inexperienced and the character most often on the receiving end of Commander Zero's scathing attitude (though Zero also refers to him as "the best lieutenant Space City has"). In one episode he is shown to be training as an XL pilot.

• Jock Campbell (voiced by John Bluthal): the chief engineer of Space City, of Scottish origin.
• Eleanor and Jonathan Zero (both voiced by Sylvia Anderson): Commander Zero's wife and young son.
• Captain Ken Ross (voiced by John Bluthal): pilot of Fireball XL7. He often needs to be rescued by the crew of XL5.
• Space Spies Boris and Griselda (voiced by David Graham and Sylvia Anderson): a villainous Russian husband-and-wife pair who first appear in the episode "Spy in Space".
• The Subterrains (voiced by John Bluthal and David Graham): a race of aliens from Planet 46.

The concept brochure for Century 21 described Colonel Zodiac and Dr Venus as the "Mr and Miss America" of 2962.[9] Venus' face was modelled on her voice actor, Sylvia Anderson.[19] Character dialogue was recorded at a studio in Borehamwood.[20]

Robert the Robot had a Perspex body with a head adapted from a plastic tumbler.[21] He was the only regular in a Gerry Anderson puppet series to be voiced by Anderson himself, who "spoke" the robot's lines (as well as those of supporting robot characters) through an artificial larynx.[21][22] As remembered by Anderson in a deleted scene of the documentary Filmed in Supermarionation (2014):

... [I]t was very, very difficult, if not impossible, to produce the sort of robot voice which would have to be a monotone. So we found out that at Edinburgh University, they were creating the human voice artificially. They gave us a vibrator – of course, everybody smiled at that – not that kind of vibrator! And it was a vibrator that people who had their larynx removed through cancer would be able to put under their chin, and it made a constant buzz. [Makes buzzing noise.] And then, of course, that sound was transmitted to the air inside the mouth. And I was then able to modulate that by mouthing the words. So let's get this straight, fellas – it was not my voice. It was the sound of the vibrator which I modulated.

Anderson also noted that due to the silent or aspirate nature of the letter "h", the larynx did not register its vocalisation; thus, Robert's customary exclamation "On our way home!" was rendered as "ON-OUR-WAY-'OME!".[21][22] Daniel O'Brien, author of SF:UK – How British Science Fiction Changed the World, describes Robert as a "very English homage" to the character Robby the Robot from the 1956 film Forbidden Planet.[2]

After working on the Andersons' earlier productions as a contractor, effects director Derek Meddings became a full-time employee of APF and formed his own unit with Brian Johnson as his assistant.[10][23][24] According to Meddings, some of the more action-packed episodes featured as many as "40 to 50" effects shots.[18] The rotating Space City control tower, whose filming model was made of wood and card, was inspired by contemporary revolving restaurants.[19][25][26][27] Fireball XL5 was the first TV series to employ front projection-based visual effects.[6]

The XL5 spaceship was designed by associate producer and former APF art director Reg Hill.[6][10] Three models were made: a seven-foot-long (2.1 m) version, which was used for close-up shots, and two smaller ones measuring 24 inches (61 cm) and five inches (13 cm).[6][26] XL5's rocket sled launch was based on rumoured Soviet plans to fire craft into space on a track ending in a ramp.[10][28] Although the 1951 film When Worlds Collide had featured a similar concept, Gerry Anderson denied that XL5's launch method was copied from this.[29] During the filming of the launch sequence, XL5 was pulled down its rail on wires by a technician running along a platform above the set.[30] Fast cutting was employed to conceal the shaking of the model.[27] Some of the series' rocket sound effects were created by recording a jet plane at a nearby airfield.[23]

The Jetmobiles – personal hovercraft that the XL5 crew use to explore the surfaces of planets – were conceived as a way of limiting the number of scenes that showed the characters walking, thus helping to conceal their lack of realistic articulation.[12][19] Originally the vehicles were to have been rocket-powered; however, tests with miniature explosives proved too destructive so the method of propulsion was changed.[24] The characters of APF's later series Stingray and Thunderbirds use vehicles similar to the Jetmobiles.[12]

The opening theme music features saxophones as well as series composer Barry Gray's first use of an Ondes Martenot.[25] The closing theme song – "Fireball", arranged by Charles Blackwell and performed by Don Spencer – was a minor hit in the UK. It spent 12 weeks in the country's music charts, peaking at number 32.[25][31][32]

According to Jim Sangster and Paul Condon, authors of Collins Telly Guide, "the sheer ambition of the show is its charm."[35] Matthew Millheiser of review website DVD Talk praises the series: "Fireball XL5 might be kitschy, might be chock-full of scientific inaccuracies and glaring anachronisms that was par-for-the-course for cheesy sci-fi of the time, and even might have a few clunker episodes in the mix. But the care, innovation, and sheer imagination in each episode are positively infectious." He goes on to describe the series as "simple, clean, clearly delineated fun" and "the perfect type of children's entertainment: it doesn't talk down to its audience, it doesn't bog down the characters with a faux sophistication or glib hipness, and it has enough dazzle, charm, and imagination to make the show enjoyable and entertaining for adults."[36] For Anthony Clark, Fireball XL5 "marks the start of the truly great Anderson-produced puppet show [...] [W]hen you sprinkle the episodes with humour, lace them with action and tie them up with Barry Gray's fantastic music, the result transcends the show's rudimentaries, transforming it into something enduringly special."[37] Comparing it to the Andersons' follow-up, Stingray, which he considers to be very similar, Clark describes Fireball XL5 as "[p]erhaps [...] a little more playful and a little less slick, but what it lacks in polish it more than makes up for in energy and pace."[38]

According to Paul Mavis of DVD Talk, the series is "not as ambitious ideas-wise" as Stingray yet "still charms, thanks to its simple yet nicely designed production and that velvety, strangely ethereal black-and-white world it creates." He also states that "while there aren't nearly as many elaborate 'hardware' set-ups as later Anderson outings [...] the budget-imposed simplicity adds an amusingly ironic, sleek modernist tone" to the series.[39] In contrast, Stuart Galbraith IV describes the "hardware" as "pretty retro even by 1962 standards", adding that the overall production "looks more like Rocky Jones, Space Ranger than Thunderbirds." On the writing, he notes that while earlier episodes are mostly "strange-planet/Earth-under-threat-type stories", there is an increasing focus on character development as the series progresses.[29] Mavis argues that the characters are limited by the fact that they were purposely conceived as "action/adventure stereotypes". On the writing generally, he considers the "old-school comic book"-style plots to be "less sophisticated than the production design, frequently falling into the same pattern: the UN-like World Space Patrol recognizes a threat from an alien civilisation, sending in Steve Zodiac and team to neutralise it ... before almost getting themselves killed."[39]

For John Peel, Fireball XL5 is one of several APF series to feature capable female characters who are weakened by negative gender stereotypes. Peel describes medical expert Dr Venus as being "relegated to secondary chores", calling this an example of "standard Anderson sexism".[40] Writing for Decider.com, Meghan O'Keefe praises Fireball XL5's humour and special effects but criticises the series' "almost incomprehensible level of misogyny [...] Dr Venus is criticised for not fetching coffee fast enough and later, when she praises Steve's heroism, he replies, 'Thanks, I think you're cute, too.'" O'Keefe also comments that the series "doesn't seem concerned with the morality or the larger social implications of space travel. Just as Dr Venus is constantly written off as a woman, the aliens we meet speak an uncomfortably foreign language and are painted as maniacal terrorists willing to go on suicide missions to destroy Earth [...] There's no nuance, but then, that clearly wasn't the goal. Anderson was clearly trying to make an entertaining show, and it's very, very amusing."[41]

Ian Fryer characterises the series as a Space Western, arguing that Steve Zodiac essentially plays the role of an interstellar sheriff. Fryer also compares David Graham's voice for Professor Matic to that of Western actor "Gabby" Hayes and the French-born Venus to Marlene Dietrich as Frenchy in the film Destry Rides Again (1939). According to Fryer, the series adapts Western stock characters to create an air of "warmth and familiarity".[42]

The series' music has been positively received. According to Clark, the closing theme song's opening lyric, "I wish I was a spaceman", had a "timely resonance" for audiences of the early Space Age.[43] Describing the series overall as "better than a lot of live-action movies", Mark Voger of NJ.com argues that the music "would be at home in any live-action thriller."[44]

• Archer, Simon; Hearn, Marcus (2002). What Made Thunderbirds Go! The Authorised Biography of Gerry Anderson. London, UK: BBC Books. pp. 70–84. ISBN 978-0-563-53481-5.
• Bentley, Chris (2008) [2001]. The Complete Gerry Anderson: The Authorised Episode Guide (4th ed.). London, UK: Reynolds & Hearn. ISBN 978-1-905287-74-1.
• Fryer, Ian (2016). "Fireball XL5". The Worlds of Gerry and Sylvia Anderson: The Story Behind International Rescue. Fonthill Media. pp. 68–78. ISBN 978-1-78155-504-0.
• La Rivière, Stephen (2014) [2009]. "A Wonderland of Stardust: Fireball XL5". Filmed in Supermarionation (2nd ed.). London, UK: Network Distributing. pp. 102–126. ISBN 978-0-992-9766-0-6.
• Meddings, Derek (1993). "Worlds of Illusion". 21st Century Visions. Surrey, UK: Paper Tiger Books. pp. 21–31. ISBN 978-1-85028-243-3.
• Sellers, Robert (2006). Cult TV: The Golden Age of ITC. London, UK: Plexus Publishing. pp. 83–88. ISBN 978-0-85965-388-6.