Mr Simonyi, who will blast off from Kazakhstan at 23:31 local time (17:31 BST) today, oversaw the creation of Microsoft's office applications Word and Excel.
Speaking to reporters alongside friend and lifestyle guru Martha Stewart, with whom he has been romantically linked, Mr Simonyi said he was excited about conducting scientific experiments on the ISS.
"We don't know what we will find but we have to go and find it," the Hungarian-born software developer said.
The adventurous tourist will blast off in the Soyuz TMA-10 spaceship with two Russian cosmonauts, Fyodor Yurchikhin and Oleg Kotov, who have been helping out the computer geek-turned-astronaut.
"They gave me a lot of advice - not to move my head, not to drink too much before the launch," Mr Simonyi joked.
While in space Mr Simonyi will share with his fellow travellers a deluxe menu chosen by Martha Stewart herself including roast quail, duck breast with capers and rice pudding.
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