'Convict in Space' by Alan Fennell

When a criminal named Deblis steals some top-secret plans from Earth and escapes into space, Steve Zodiac sets off in Fireball XL5 in pursuit. He eventually captures Deblis, but the villain has managed to hide the plans and refuses to reveal their location. Three months later, Deblis has been sentenced to spend the next twenty years in the Space Pen. However, Mr. and Mrs. Space Spy have devised a plan to rescue Deblis, learn the location of the blueprints, and then kill him once they have the plans; they send a fake distress call, and when XL5 tries to help, the two villains capture Matt and use him to bargain for Deblin’s release…

Paul Maxwell (Colonel Steve Zodiac / Research Control), Sylvia Anderson (Doctor Venu / Griselda Space Spy), David Graham (Professor Matt Matic / Lieutenant 90 / Boris Space Spy / Grothan Deblis), John Bluthal (Commander Zero / IPN Newsreader), Gerry Anderson (Robert the Robot)

Directed by Bill Harris
Produced by Gerry Anderson
Associate Producer Reg Hill

TX (UK - ITV):
13th May 1963

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