In 1999, the South African-born Mark Shuttleworth sold his internet company, Thawte, which provided digital certificates for websites, for more than $500m (£254m).

After spending $20m on a trip into space, he started the Ubuntu project - named after an African word meaning "Humanity to others", or "I am what I am because of who we all are" - which has since become the most popular GNU/Linux distribution.

Technology Guardian: To what extent did your space trip feed into...