Kayo finds Captain Lee Taylor, whom International Rescue need to help a space vehicle, the Helius, transporting colonists to Mars. A proton storm cause a systems malfunction and the ship overshoots Mars and heads straight for the asteroid belt. Thunderbird 3 launches with Alan, Scott and Taylor and a POD to fend off the asteroids. When trying to avoid a large asteroid the Helius is damaged and International Rescue must try and find a way to land the ship on Mars, even though it was only designed to orbit the planet.
Kayo: "It's Kayo. And I wish you'd find less dangerous ways to spend your retirement."
John: "The Helius is a Transport ship designed to reach Mars and send landing pods to the life support systems on the surface. Dozens of families are on board and would be the first to actually live on the planet."
Alan: "Unless you count all the aliens!"
John: "Ignore him."
Taylor: "Like you boys say, Thunderbirds are off! Wait that's not it, Thunderbirds have left the building! Thunderbirds are, eh-"
Taylor: "That's the one."
Scott: "Settle in, everyone, even with our enhanced engine power we got a long flight ahead of us.
Alan: "No problem, I've got hours of alien footage to pass the time!"
Scott: "A really 'long' flight."
Scott: "You and Dad were the first team to land there."
Taylor: "Nearly didn't. Dust storm almost made us call off the descent, but we took the risk and went anyway. Jeff said humanity never got anywhere taking it easy, I've always remembered that. Gordon here should take it to heart every time he pilots Thunderbird 3."
Alan: "Uh.. I'm Alan, sir. Gordon's in Thunderbird 4."
Taylor: "Right.. maybe I better pull up that chart."
Scott: "Head in and make contact with the passengers."
When going down into Thunderbird 3's hangar Alan is sitting on the right hand side (screen left) instead of the left but still comes out in the pilot seat position.
This marks the second occasion that one of Thunderbird 3's Pods have been destroyed, the first being Comet Chasers and the fourth time a pod has been destroyed in the entire series.
There is a continuity error involving the talk about aliens, Lee Taylor tells Alan that he's never seen any and it's dismissed as there being no such thing in existence, however in Deep Searchearlier in the season, Alan and Gordon come into contact with an alien life form while in Thunderbird 4 on Europa. It is possible that this episode was intended to be broadcast before Deep Search.