The private sector is muscling in on space exploration, and the biggest commercial opportunity could be tourism.

Ed Butler meets the star-gazers at the Future in Review conference of tech entrepreneurs in Utah. Ariel Ekblaw, who founded the Space Exploration Initiative at MIT, discusses the logic of self-assembling space hotels. Nasa chief scientist Dennis Bushnell talks cosmic beach combing.

And Chris Lewicki, head of space mining start-up Planetary Resources, explains why he thinks it makes more sense to mine water on asteroids than bring it with us from Earth.

(Picture: Fictional space station with astronauts and space ships; Credit: ZargonDesign/Getty Images)