Prof. Brian Cox looks at the next stage of space travel, by private individuals.
Cox interviews people behind the private companies and billionaires who are funding their way to space: not just tourism, but also mining asteroids and creating colonies on Mars. Much of this comes down to the X-prize, to create reusable space craft.
Among the people featured include Sir Richard Branson with Virgin Galactic and Amazon founder Jeff Bezos of Blue Origin.
The 21st Century Race for Space is on BBC Two at 21.00.