A Mini rocket was a form of rocket craft found in the 22nd century. They were very small and agile, but could only fit up to three passengers and were easily damaged.
The Second Doctor, John and Gillian found a mini rocket from 2150 on display in the Time Museum; after they came under attack by Cybermen, they attempted to use the craft to get away. Though the Doctor's swift piloting confused the Cybermen for a time, he was unable to find a way out of the Museum, and the mini rocket was eventually shot down. (COMIC: The Time Museum)