The Calypso was a spacecraft built in 2040, and piloted by Asher and Finn with a robot called Braman. It was returning from an 8-year data-collecting mission when it developed a malfunction and headed towards Earth. According to the computer data-log, it was Braman who sent the ship back towards Earth whilst the two pilots were inside their sleeping modules.
When International Rescue came to the aid of the crew, Scott also had to collect all of the computers from the ship aboard Thunderbird 3 before it started re-entry. But, as the Calypso was still on a crash course for a city in Western Africa, Braman (on Brains' orders) guided the ship away from the city. However, it blew apart on re-entry and crashed into the water, sinking into the depths of the ocean.
The Calypso appeared in SOS Part 1.