The '''''Zero-X''''' (spelling variants include: "''Zero X''" or "''Zero - X''") is a fictitious Gerry and Sylvia Anderson's Thunderbirds'' feature film ''Thunderbirds are GO'' (1966) and in the first episode of the next Supermarionation series, ''Captain Scarlet and the Mysterons'' (1967). 

==Construction==
The first manned craft to land on aerofoils) are attached to the main body at the front and rear of the craft. Finally, a heatproof nose cone with an aluminum exoskeleton protects the MEV during lift-off; it is jettisoned shortly after leaving the Earth's atmosphere, and is the only non-reusable part of the spacecraft.

The lifting bodies act as wings to allow the craft to operate from a runway like a conventional aeroplane, and carry multiple jet engines to reduce the amount of fuel needed for the main body's chemical engines. They separate from the main body when the craft is at a sufficiently high altitude and fly back to base; on re-entry, they rendezvous with the spacecraft and dock with it to again act as wings and provide propulsion in the atmosphere. On reaching Mars, the MEV detaches from the main body, which is left in orbit piloted by a single astronaut, and descends towards the planet's surface. At the surface the MEV extends caterpillar tracks to negotiate the rocky terrain.<ref name="TaG">''Thunderbirds are GO'' (1966), Century 21 Cinema/United Artists</ref>

The concept of a reusable first-stage lifting body (or in this case, bodies) boosting a smaller spacecraft to high altitude for more efficient use of its propulsion was in direct competition with the vertical-ascent rocket doctrine in the 1960s as a means of achieving spaceflight, and ultimately lost out to it, as even the Space Shuttle - which lands as a conventional aircraft - makes a vertical rocket powered ascent in the 'classical' manner. The ''Zero-X'' contrasts in this way with the ''Thunderbird 3'', which, though nominally more advanced (hinted at because of its secrecy), is still a vertical-ascent rocket.

==Appearances==
===''Thunderbirds Are GO''===
The first manned mission to Mars ended in failure after the ''Zero-X'' spacecraft was accidentally sabotaged by the Hood, who had stowed aboard the craft to photograph its wing mechanisms. The crew managed to escape and two years later a second ''Zero-X'' craft successfully reached Mars in September 2065. However, soon after touching down on the surface, the MEV was attacked by Martian Rock Snakes. While the astronauts managed to escape, the lifting body control-systems onboard the MEV sustained damage during the confrontation, causing the ''Zero-X'' to crash upon its return to Earth, landing in Craigsville, U.S., roughly 20 miles from its launch site, the fictitious Glenn Field Spaceport, Nevada. The crew survived, having been saved at the last minute (quite literally) by International Rescue.<ref name="TaG" />

In both missions, the ''Zero-X'' was manned by three crew and two scientists:

* Paul Travers (Captain)(for the overall mission)
* Greg Martin (Space Captain)(for the flight)
* Brad Newman (Space Navigator) 
* Dr. Tony Grant (Astrophysicist)
* Dr. Ray Pierce (Astronomer)

===''Captain Scarlet and the Mysterons''===
A further ''Zero-X'' mission returned to Mars in 2068 sponsored by Spectrum in search of the source of alien signals detected from Earth. The crew's hostile actions lead to a "war of nerves" with the Captain Black, gave the order to fire upon the facility after mistaking scanning devices for weapon emplacements and fearing they were about to be attacked. Following its devastation, the three men crew of the MEV then witnessed the miraculous rematerialisation (retrometabolism, in the language of the television program) of the Mysteron city, and for their act of aggression the Mysterons took control of Captain Black’s mind and body as the principal agent of their vengeance.<ref>''Captain Scarlet and The Mysterons'' (1967), Century 21 Television/ITC - episode 1: "The Mysterons"</ref>

It is never specified whether Black and the crew actually died on Mars, but when the ''Zero-X'' returned to Earth with Black as its only occupant, he vanished after the craft reached Glenn Field Spaceport, and it wasn’t long after this that the people of Earth received their first threat from the Mysterons from Mars.<ref>''Captain Scarlet and The Mysterons'', audio adventure, MA-151 - introducing Captain Scarlet</ref>

thumb|Speelgoeduitvoering van Zero-X.
De '''Zero-X''' (soms ook gespeld als "Zero X" of "Zero - X") is een fictief ruimteschip dat voorkomt in meerdere Gerry en Sylvia Anderson. Hoewel het publiciteitsmateriaal voor de verschillende Supermarionationseries en het stripboek ''TV2000'' referenties bevatten over connecties tussen de verschillende series, is de Zero-X de enige bevestigd connectie tussen twee series. Het ruimteschip verscheen namelijk in de eerste ''Thunderbirds'' film ''Thunderbirds are Go'' (1966), en in de eerste aflevering van de serie ''Captain Scarlet and the Mysterons'' (1967). 

==Constructie==
De Zero-X was bedoeld voor de eerste bemande vlucht naar Mars. Zero-X bestond uit een hittebestendige neuskegel met een aluminium exoskelet. Het hoofdgedeelte van het voertuig bleef in een baan om mars. Verder kon een onderdelen van de Zero-X, De Martian Exploration Vehicle (MEV), loskoppelen van het hoofdgedeelte via twee herbruikbare en op afstand bestuurde "lifting bodies". Deze MEV was bedoeld voor onderzoek op het oppervlak van de planeet. <ref name="TaG">''Thunderbirds are GO'' (1966), Century 21 Cinema/United Artists</ref>

==Verschijningen==
===''Thunderbirds Are GO''===
De eerste Zero-X werd gelanceerd aan het begin van de film. Door toedoen van The Hood, die aan boord was geglipt om foto’s te maken, stortte de Zero-X echter in zee. De bemanning kon ontkomen via de ontsnappingscapsule.

Twee jaar later werd een tweede Zero-X gelanceerd, ditmaal onder toezicht van International Rescue. Dit keer was de missie succesvol, en de MEV landde op Mars in september 2065. De missie werd geleid door drie crewleden en twee wetenschappers:

* Paul Travers (Kapitein)
* Greg Martin (Copiloot)
* Brad Newman (Ruimte Navigator) 
* Dr. Tony Grant (Astrofysicist)
* Dr. Ray Pierce (Astroloog)

Op Mars kwam de bemanning oog in oog met enkele rotsslangen, en kon maar net ontkomen. Wel raakte Zero-X dermate beschadigd dat bij terugkeer op Aarde het toestel neerstortte en de ontsnappingscapsule dienst weigerde. Door tussenkomst van International Rescue kon de capsule worden gerepareerd en de crew gered, maar de Zero-X zelf stortte neer in Craigsville. <ref name="TaG" />

===''Captain Scarlet and the Mysterons''===
In 2068 vond nog een Zero-X missie plaats, ditmaal gesponsord door Spectrum. De reden dat deze missie werd ondernomen was om vreemde signalen die van de planeet kwamen te onderzoeken. De crew, onder leiding van Captain Black, vernietigde op Mars een stad van de Mysterons, waardoor dit ras een terreuractie tegen de Aarde begon. Als onderdeel hiervan namen de Mysterons Captain Black over via hun proces van retrometabolisme en gebruikten hem als hun belangrijkste agent.<ref>''Captain Scarlet and The Mysterons'' (1967), Century 21 Television/ITC - aflevering 1: "The Mysterons"</ref>

Het werd niet duidelijk wat er met de rest van de Zero-X crew gebeurde, maar bij terugkeer op aarde was Captain Black de enige aan boord. Kort na de landing verdween hij spoorloos, waarna Spectrum de eerste bedreiging van de Mysterons te horen kreeg. <ref>''Captain Scarlet and The Mysterons'', audio adventure, MA-151 - introducing Captain Scarlet</ref>