When the Sun Probe rocket is unable to pull away from the Sun, Brains realizes that a powerful radio beam is needed to fire the Probe's retros.
Jeff Tracy then decides to mount a two-pronged rescue: while Thunderbird 3 heads for space to try to trigger Sun Probe's retros directly, Virgil flies Thunderbird 2 to Mount Arkan so that beams from the powerful Mobile Transmitter will have a better chance of reaching Sun Probe from high up on the mountain.
The Mobile Transmitter[]
The first attempt by Virgil and Brains from the Transmitter truck fails to fire the sunprobe's retros. Closer still, Alan makes a third attempt and succeeds in activating the Probe's retros and enables it to move away from the sun.
Thunderbird 3 in Trouble[]
Thunderbird 3's retros now fail, Tin-Tin has collapsed in the extreme heat, leaving the signal booster turned on, sapping the ship of power.
The Wrong Box[]
Brains realizes that he can jam Thunderbird 3's safety beam signal with the mobile computer in Thunderbird 2, unfortunately, Brain's prototype robot Braman has been packed by mistake. However, Braman is able to complete the necessary calculations and the realigned transmitter beam successfully jams Thunderbird 3'3 safety beam. The retros fire and Thunderbird 3 returns safety to Earth.
