The Mighty Atom
Season 1, Episode 14
The Mighty Atom 01
Original Transmission December 30, 1965
Written by Dennis Spooner
Directed by David Lane
Edited by Harry Ledger
Production Order
The Uninvited
Vault Of Death
Broadcast Order
Attack Of The Alligators!
City Of Fire

The Mighty Atom is the 6th produced episode and the 14th broadcast episode, of the first series of Thunderbirds.


International Rescue have to stop a nuclear reactor in Africa from exploding while they unknowingly are being spied upon by The Hood.


The episode begins some months prior to the formation of International Rescue. Deep in the Australian outback a seawater-purification plant has been built under heavy secrecy. It is designed to pump seawater from the ocean, desalinate it and then pump it out into the desert in a bid to reclaim land from the desert. In order to achieve this, the plant contains its own nuclear fission reactor at the heart of the complex.

A press-tour is being conducted around the plant by a plant tour-guide, in a publicity event intended to reveal the new project to the world, and prove the safety of nuclear power. In somewhat fate-tempting words, the tour guide tells the reporters,

"The reactor is under the complete control of the project staff. Nothing can go wrong."

Unbeknownst to anyone, The Hood is also in the plant that day, intending to acquire secret details of the project and sell them on the black market for a fortune. However, he is discovered by a security guard and in the ensuing gun-battle, manages to start a gas explosion which leads to a major chemical fire. The plant is evacuated of all non-essential personnel, but the plant controllers remain in a bid to avert a nuclear accident. They attempt to shut down the plant by fully inserting the graphite control rods, as the fire is now raging out of control and has reached the reactor containment buildings. However the rods are immovable due to unknown reasons, and the reactor overheats to the point that a runaway reaction occurs and a steam explosion becomes inevitable. The plant is abandoned and the evacuation of the remaining staff occurs just in time before a steam channel bursts, causing a catastrophic nuclear explosion, completely destroying the plant and severely contaminating central Australia with radioactive materials. A state of emergency is declared and an emergency press conference is called, held by General Speyer, who states that,

"Unless the weather takes a hand and a strong wind picks up... Melbourne will have to be evacuated."

Luckily a wind does pick up, and the cloud of radioactive materials is blown out into the Indian Ocean where it is dispersed.

Following this disaster, The Hood continues his campaign to steal nuclear state secrets. He attends a top-secret scientific meeting in the guise of Professor Langley, which is being held by Professor Holden, an expert in scientific espionage. Holden demonstrates the latest gadget - a robotic camera, which is designed to take photographs of the profile of the human face. Therefore if introduced into a top-secret laboratory, the robot would continually photograph the technicians, who would be working at the dials and would therefore appear in the photographs as well. In order to remain unnoticed, the robot looks and behaves like an ordinary mouse, including running and hiding. The Hood, recognising the potential of such a device, overpowers the scientists by hypnosis and steals it.

Events move forwards by a year. International Rescue has begun operations, and Lady Penelope is visiting Tracy Island, which coincides with Alan flying to Thunderbird 5 to relieve John. However not a lot is happening, as there have been no emergency call-outs for some time, and Penelope is frustrated by this as she wants to attend her first rescue mission before she leaves.

Meanwhile, The Hood is infiltrating a new (and controversial) nuclear-powered desalination plant situated in the Sahara Desert. The crew (including a former-member of the Australian control staff) are unaware of his presence, and he successfully uses the miniature robot to obtain detailed photographs of the plant. However, he then realises the potential with this plant for luring International Rescue to the scene and using the robot again to obtain their secrets. He therefore sets and detonates a large number of incendiary devices around the plant, and causes a similar chemical fire to the one in Australia. This one, however, burns out of control almost immediately, and quickly engulfs the reactor buildings, initiating a runaway chain reaction. The control staff realise that the Australian disaster was partly caused by a plant design flaw - the inability to shut down the seawater intake feeding both the desalination plant and the nuclear reactors. Fearing an even more catastrophic disaster than previously, and with the plant and fire completely out of control, they make an emergency distress call, which is picked up by Alan in the space station.

Thunderbirds 1, 2 and 4 are scrambled (including the delighted Penelope) and arrive at the plant with mere minutes before the predicted steam explosion occurs. Thunderbird 4 containing Gordon Tracy has been dropped into the sea off the North African coast and Gordon positions himself in front of the seawater intake pipes, deep underwater. While Penelope is told to remain on board Thunderbird 2, Virgil and Scott rush to the plant control room, and enter the reactor containment building in order to manually insert the graphite control rods in coordination with Gordon. They successfully insert the rods, and Thunderbird 4 destroys the intake pipes at the exact moment, shutting down the entire plant and the nuclear reactors simultaneously, and averting the nuclear disaster by less than a minute.

The Hood, in the meantime, has deployed the Mighty Atom inside Thunderbird 2, and is hoping to obtain photographs of the top-secret aircraft's interior. However Penelope is still on board, and the robot takes pictures of her while she stands on the pilots seat screaming. The episode ends with The Hood back in his jungle temple hideout, examining the photos the robot took. When he realises that he has a roll of film full of Penelope screaming and none of the aircraft, he flies into a rage and smashes the robot, destroying it and all the film (including that taken previously in the Saharan plant.)


Regular CastEdit

Guest Voice CastEdit


  • Penelope makes her first visit to Tracy Island since International Rescue became operational and also takes part in her first rescue mission. It is stated that International Rescue were not operating when the Australian plant exploded 12 months ago.
  • A teletype printout gives the date on which the atomic cloud is blown away from Melbourne as October 6th and it is then stated that the explosion of the plant took place the previous Monday. If this is 2064, October 6th is a Monday, so the explosion occurred on September 29th.
  • The rescue plane that evacuates the personnel of the Australian plant is the TX 204 target-carrying aircraft from Trapped In The Sky.
  • This is the only episode out of the entire series to feature all of the Regular Cast members and all of the Thunderbird Crafts.
  • This episode shows the first actual appearance of Thunderbird 4.


  • The Mighty Atom is programmed only to photograph the profiles of human faces, yet it is seen taking photographs of the control panels at the Saharan plant when no one is in the room.
  • An edition of the Melbourne Herald newspaper is seen to be dated Friday, December 24, 1964. This date is also seen on newspapers in Edge Of Impact, The Impostors and Cry Wolf but was not intended to be legible to television viewers. (Oddly, December 24th, 1964 was actually a Thursday.)
  • When the 2nd Reporter says to the 1st Reporter, "Panics over then. Did you hear the cloud got blown away." It is said by David Graham in stead of Matt Zimmerman.

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