'The Firefighters' by Alan Fennell

A mysterious gas cloud approaches Earth, emitting huge fireballs that start blazes across the world. Commander Zero sends Fireball XL5 to investigate, but as the ship closes in on the cloud, a fire breaks out inside the vessel; while Robert takes the controls, Steve and Matt manage to fight the fire, but the damage leaves Steve no choice but to return to Earth for repairs. With just twelve hours to go before the cloud enters the atmosphere and destroys the world, Matt devises a plan to contain the cloud inside an abandoned space station – but can he complete the work in time..?

Paul Maxwell (Colonel Steve Zodiac), Sylvia Anderson (Doctor Venus), David Graham (Professor Matt Matic / Lieutenant 90 / Zoony the Lazoon / Space Station 9), John Bluthal (Commander Zero), Gerry Anderson (Robert the Robot)

Directed by John Kelly
Produced by Gerry Anderson
Associate Producer Reg Hill

TX (UK - ITV):
11th November 1963

Notes:
*Featuring Colonel Steve Zodiac, Venus, Professor Matt Matic, Commander Zero, Lieutenant 90 and Robert the Robot