The Dragon 1 spacecraft was designed to carry cargo to

SpaceX was shortlisted for evaluation under the Nasa cargo programme in 2006. But by 2008, SpaceX and Tesla, the electric car manufacturer in which Musk had invested, were running low on cash. Musk was faced with an impossible choice: "I could either split the funds that I had between the two companies, or focus it on one company - with certain death for the other," he told Business Insider in 2013.

"I decided in the end to split what I had and try to keep both companies alive. But that could have been a terrible decision that could have resulted in both companies dying."

Fortunately, on 23 December 2008, Nasa awarded SpaceX with a $1.6bn contract to ferry cargo and supplies to the ISS. Describing his reaction, Musk said: "I couldn't even maintain my composure, I was like: 'I love you guys'."

The company's Dragon 1 capsule could carry cargo and supplies, but not humans. Nevertheless, it represented a milestone for the company.

In November 2008, Barack Obama had been elected president. His administration kicked off a review of the human spaceflight programme, which led to the cancellation of his predecessor's plan to return to the Moon (known as Constellation). สล็อตฟรี