The Utopia Project rocket was an immense rocket. Its purpose was to transport the last humans in the year 100,000,000,000,000 to the fabled planet of Utopia and escape the reaches of the savage Futurekind.
The rocket used some kind of combusting fuel to power the engines, but due to its size an immense "foot" was required to get it off the ground.
The Tenth Doctor, Martha Jones, and Jack Harkness helped a man named Professor Yana finalise the launch of this rocket with his assistant, Chantho. However, it was during these final preparations that Martha discovered a fob watch in Yana's possession, which he had unknowingly used as the receptacle of a Chameleon Arch. It held the dormant personality of the Master, Yana's true identity. After Yana opened the watch, he reverted back to the Master's original persona. He immediately betrayed Chantho and attempted to sabotage the rocket launch. Despite the Master's interference, the rocket successfully made liftoff. (TV: Utopia) Unfortunately, upon arriving at their destination, they found the world dark and deserted and cold, and they were still at mercy from the collapse of the universe. To survive, they changed themselves, cannabalised themselves, regressing into children before they changed completely into a race of cyborgs and aligned themselves with the Master, who named them Toclafane. (TV: The Sound of Drums)