Old Tom - Season 1 Episode 4 Blast Off!

Angela goes shopping for a playhouse for Old Tom and ends up buying an old rocket ship. Old Tom loves it and, with his best friend Lucy, they decide to fly it to Mars. Angela thinks they are just playing (after all, the booster rockets have been taken off) and she goes along with their little 'fantasy'. However, while she is cleaning the rocket, it takes off - Old Tom had used one of Angela's vacuum cleaners as the propulsion. The rocket flies off into space with Old Tom on the inside, and Angela on the outside, battling meteors and satellites. Finally, Old Tom lets her in, just as the rocket careens out of control and crash lands on an unknown planet. Angela is sure they're on Mars - but one of the aliens looks familiar. It's Lavinia, and they have literally 'crashed' her garden party.