Charles Simonyi has successfully blasted off from the Baikonur cosmodrome to become the last space tourist for the foreseeable future, and the first to make the trip twice.
Simonyi, 60, paid $35m (£24m) for his second trip into orbit, having visited the International Space Station in 2007. On this visit he will spent 13 days in orbit after docking on Saturday.
The launch was watched by Simonyi's wife Lisa Persdotter and his former colleague at Microsoft Paul Allen.
"It's fantastic to see a launch, but when it's one of your friends it's just something so special," Allen told Associated Press.
Allen said he would not be interested into getting into orbit using Russian technology, but is hoping to using his own spacecraft. He is a major investor in SpaceShipOne, the first commercial space operation.
"We applaud Charles on his continued commitment and investment to commercial spaceflight. Having a repeat orbital client demonstrates to the world that participating in a space mission is truly a magnificent and awe-inspiring experience," said Eric Anderson, president of Space Adventures, which organised the trip.
"Charles is an inspiration and it has been a pleasure and an honour to assist him in living his dream, twice."
Simonyi is likely to be the last space tourist for a while. The International Space Station is shortly to be expanded to house six permanent crew, and the Russian boosters that supply it will not have space for paying passengers.
This is potentially bad news for Google co-founder Sergey Brin, who has already paid a deposit for a proposed 2011 flight. However, Space Adventures has not ruled out flights at some later date.
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