"Heavy Metal" is the 13th episode of Thunderbirds Are Go!. It was first broadcast on Saturday June 20th, 2015.


Alan flies Brains to the Quantum Research Center in Switzerland, where the Supreme Hadron Collider is housed. There, they meet Brains’ old University friend, Professor "Moffie" Moffat who Brains has a crush on. She demonstrates the operation by activating the collider and Alan starts the atomic collision. Up on Thunderbird 5, John glimpses an unknown meteorite falling through Earth’s atmosphere and heading straight for Switzerland. He tells International Rescue that the meteorite has crashed in downtown New Geneva. Virgil lands there in Thunderbird 2 and finds out that the meteorite was a satellite. Alan thinks the Hood brought it down. Suddenly, a plane passing over Switzerland descends uncontrollably and Scott heads out in Thunderbird 1 to save it.

Scott tries to pull the jet out of its dive but Thunderbird 1 starts to fly out of control. Brains says that there was no sign of sabotage. After Alan thinks the plane is dragging Thunderbird 1 down, Brains says that the plane is a Botchley Skyliner with a crew weight of 318.7 metric tons. He then explains that Thunderbird 1 is in an inclined dive of 6.7G but with a vertical thrust of 470 000 pounds which is enough to pull 6.4 Skyliners. They guess that gravity here isn’t normal and John runs a gravity scan on Thunderbird 1. Brains tells Scott that he is caught in a gravity well. Alan thinks gravity can make him go faster and tells Scott to accelerate to 9Gs to get out of the gravity well and Thunderbird 1 and the plane safely manage to avoid crashing.

Back at the Quantum Research Centre, Moffie tells Brains and Alan that they have been scanning localized gravitational anomalies when the Supreme Hadron Collider went online. Brains explains that the collider had the right conditions to generate the gravity well when it was activated. They try to shut it down but the gravity well is still active and self-sustaining, pulling the World Wide Space Station out of orbit. As everything in the control room goes weightless, Brains says that they need to stop the collider physically. He explains that the process would require Thunderbird 4 with its compact pressurized structure.

Virgil and Gordon arrive with Thunderbird 4 and safely fly into the heart of the gravity well where Gordon is lowered into the collider's chamber. Thunderbird 2 gets caught in the gravity well and Alan takes off in the Helipod to help Virgil. As Alan struggles to get higher, Scott arrives in Thunderbird 1 to help. After several plans to shut down the collider, Gordon destroys it with Thunderbird 4's demolition missiles, causing the gravity well to dissipate. As the Tracy brothers touch down, Gordon says that he was about to get squashed and Alan jokes that he has gotten a bit shorter. When Moffie says that the collider is destroyed, Brains says that it can be rebuilt better than before and she kisses him on the cheek.


Regular CastEdit


Note: the following section is large. As such, it is hidden by default.




(under construction)

Equipment UsedEdit

International Rescue Equipment UsedEdit

Non-International Rescue Equipment UsedEdit

  • Supreme Hadron Collider
  • Botchley Skyliner
  • GDF Satellite
  • Worldwide Space Station



  • This is the final episode of Season 1's first half to air. 
  • This episode marks the first time Thunderbird 4 has been used for a rescue mission not underwater.
  • The Supreme Hadron Collider is a direct homage to the Large Hadron Collider in Switzerland at CERN.
  • Dr. Moffat refers to Brains as Hiram. This is obviously a dreadfully ill-informed reference to the alias Brains used in Alias Mr. Hackenbacker.

Foreign titlesEdit

  • Dutch: Zwaartekracht (Gravity)
  • French: Métaux lourds
  • Spanish: Metal Pesado
  • Japanese: 重力の井戸 (Well of Gravity)