- "I fail to see why you're still laughing, Virgil. I just don't like mice, that's all."
— Lady Penelope Creighton-Ward
A year after The Hood's first attempt to steal the secrets of an Australian nuclear power plant ended in disaster, he's ready for another go - but, this time, with a very different, and utterly unorthodox, approach...
Having stolen a new anti-espionage device called the "Mighty Atom" - cleverly guised as an ordinary-looking pocket mouse - he uses the high-tech little creature's photographic acumen to secure detailed images of an atomic plant in the Sahara Desert.
Flush with his new success, he elects to take his nefarious plans one big step further - by deliberately sabotaging the installation, to lure out International Rescue...
- Main article: The Mighty Atom/Storyline
- Main article: The Mighty Atom/Transcript
- Jeff Tracy - Peter Dyneley
- Scott Tracy - Shane Rimmer
- Lady Penelope Creighton-Ward - Sylvia Anderson
- Virgil Tracy - David Holliday
- Alan Tracy - Matt Zimmerman
- Brains - David Graham
- Parker - David Graham
- Tin-Tin Kyrano - Christine Finn
- Gordon Tracy - David Graham
- John Tracy - Ray Barrett
- Kyrano - David Graham
- Grandma Tracy - Christine Finn
- The Hood - Ray Barrett
- Eddie Kerr (2nd Reporter) - Matt Zimmerman
- Reactor Controller Wade - Ray Barrett
- Reactor Controller Collins - David Graham
- General Speyer - Ray Barrett
- Professor Holden - Peter Dyneley
- Reactor Control Assistant - Shane Rimmer
- Press Officer - Matt Zimmerman
- Australian Plant Tour Guide - David Graham
- 1st Reporter - Peter Dyneley
- 3rd Reporter - David Graham
- Australian Plant Fire Chief (voice only, not seen on screen)- Ray Barrett
- Australian Plant Guard - David Graham
- 1st Scientist - Ray Barrett
- 2nd Scientist - David Graham
- 3rd Scientist - David Holliday
- Australian Plant Tannoy - (voice only, not seen on screen) Sylvia Anderson
- Australian Plant Control (voice only, not seen on screen) - David Graham & Ray Barrett
- ?? - John Tate (?)
- Atomic Irrigation Station Tour Bus occupants
- Press Conference (Australia) attendants
- Research Unit Guard
- Two scientists at Professor Holden's Demonstration
International Rescue Equipment UsedEdit
Non-International Rescue Equipment UsedEdit
- Atomic Irrigation Station (Australia)
- Atomic Irrigation Station Tour Bus
- Eastern Australian Fire Department
- Government Research Unit
- The Hood's Temple
- Melbourne Herald Newspaper
- Press Conference (Australia)
- Saharan Atomic Station
- Sea Water Intake (Atomic Plant)
- The Mighty Atom is noteworthy for being the only series episode in which all five Thunderbirds craft appear (excluding the feature films).
- It's also the only episode in which all of the series' major characters appear (the Tracy (7) and Kyrano families (3, including The Hood), plus Brains, Penelope and Parker - 13, in all!).
- Originally a half-hour episode filmed in late 1964, it was extended in mid-1965.
- For subsequent 'cliffhanger' formats broadcast in some countries, the first installment ends with The Hood gloating in his temple that the secrets of the world will soon be his.
- The Target Carrying Aircraft first seen in Trapped in the Sky returns, and is used by the Australian Atomic Station workers to escape from the nuclear explosion at the start of the episode.
- The Conference Hall's exterior set makes an appearance, and would go on to be reused in Cry Wolf, The Impostors, and Ricochet as entirely different buildings.
- The newspapers seen rolling off the presses after the radioactive cloud is blown away are actually copies of the Coventry Evening Telegraph.
- One of the very few times Thunderbird 2 is seen flying without a pod.
- At the meeting with Professor Holden, The Hood has assumed the guise of one 'Professor Langley'.
- This is the only episode where the first line of text ("The") is in a smaller font size than the next line of text ("Mighty Atom").
- Main article: The Mighty Atom/Goofs
- French: Sabotage à l'usine atomique
- German: Die Supermaus
- Spanish: El poderoso átomo; El átomo poderoso (DVD)
- Italian: Nube sull'Australia
- Dutch: De geheime foto's (TV) De machtige atoom (VHS, DVD)
- Japanese: 原子炉の危機
- ↑ According to IMDb.com, John Tate voiced "various characters" in this episode.