As Elon Musk vows to head into Mars in the next few years, space travel is no longer just for the movies. Companies across the globe are competing to commercialise space - and these four are close to winning the race.
1. Richard Branson
The billionaire made his move into space tourism with Virgin Galactic, founded in 2004. The company – which describes itself as the “world’s first commercial spaceline” – plans to run with the reusable plane, SpaceShipTwo, released in 2016 after the original space plane model broke apart midair in a test, killing its pilot. Branson has said that he will be very disappointed if he is not in space himself in 2018.
2. Jeff Bezos
The Amazon chief executive founded Blue Origin in 2000 to help aspiring astronauts head by rocket into space, although it has quickly turned into a rivalry with Musk's SpaceX. Progress has been notably slow, but this year Bezos announced he is hoping to make “Amazon-like” deliveries to the moon by 2020, where items needed for experiments and future human settlement on the moon will be delivered.
3. Jose Mariano Lopez-Urdiales
The founder of Spanish company Zero2Infinity does not see the need for large rockets when it comes to space travel. Started in 2009, Lopez-Urdiales and his team are currently working on getting passengers near space using only pressurised capsules beneath helium balloons. Passengers could go to the top of our atmosphere to see the Earth from above and back in one day.
4. Denis Tito
This American businessman became the first orbital space tourist in 2001. The space rookie paid $20m to get on to the Russian Soyuz Spacecraft and spent a week in space. He has since outlined his plans for a private mission to Mars in 2018 - although he seems to have gone rather quiet since he unveiled his plans in 2013.
... and one politician: Wan Hu
Branson, Musk et al aren't the first lone rangers to try to get into space. A Chinese official attempted to get to the moon some time in the 16th century by attaching rockets made of bamboo filled with gunpowder to the bottom of a wicker chair. It goes without saying that this was not a successful attempt at space travel...