Igor Kutsenko, who runs an advertising firm in Moscow, told a Virgin Galactic news conference in the Russian capital that he and his business partner, Sergei Tyaglov, had bought tickets 18 months ago, and that he had also reserved tickets for his parents, both in their fifties.
Tyaglov said: "I look to fulfilling my childhood dream."
They paid $200,000 each for a thrill ride to the edge of space on the SpaceShipTwo, the first commercial six-passenger space vehicle. They will blast off from a launch pad currently being built in New Mexico
Another businessman due to take part in the flight, Timur Artemyev, said: "In buying the tickets, my wife and I wanted to be the first couple to fly toward the edge of space."
The SpaceShipTwo, due to begin test flights this year, will take the passengers to an altitude of 110 km (68.3 miles) during a two-hour flight with a four-minute period of weightlessness, when passengers will be able to release themselves from their seats and float around the cabin.
The tourists are to undergo three days of intensive training before the flight.
A total of 250 people across the world, including 11 Russians, have booked tickets for suborbital flights with Virgin Galactic. Another 85,000 people have filed flight applications on the agency's website.
The founder of the Virgin Group, British billionaire Sir Richard Branson, earlier said he and some of his family members would take a flight on SpaceShipTwo a year or so before commercial flights are launched.
A host of other companies are working on commercial passenger suborbital spaceflights, as the infant space tourism industry looks to take off. Virgin Galactic's most likely competitors include EADS Astrium, Rocketplane Limited, Space Adventures, and the Benson Space Company.
Russia is currently the only country which provides space flights for tourists. Flights blast off from the Baikonur space center in Kazakhstan. The trip, which lasts abound a week, costs around $30 million.