Updated

He paid $21 million to soar into space. He didn't get to go. Now he wants his money back.

Japanese Internet zillionaire Diasuke Enomoto last month filed suit against Vienna, Va.-based Space Adventures, claiming the company pressured the Russians to kick him off a September 2006 Soyuz mission to the International Space Station because someone else was willing to pay more.

Enomoto had been in astronaut training for months in Moscow when the Russian Federal Space Agency suddenly told him his kidney stones had gotten too large for him to safely go into space, according to a report in Wired magazine.

With less than a month to go before launch date, he was replaced by American entrepreneur Anousheh Ansari, who became the first woman to pay her way into orbit.

Enomoto claims in his lawsuit that the kidney stones were only a ruse, since he'd passed several previous exams, and that Space Adventures forced him off the flight because he'd resisted the company's attempts to shake him down for more money.

He says Space Adventures suddenly wanted $10 million extra for a spacewalk that had been part of the original deal, and that he was pressured to become an investor in the company.

When Ansari did agree to invest in Space Adventures, Enomoto says, he was out — and the company was paid twice for one seat aboard the Soyuz.

• Click here to read the full story on Wired.com.

• Click here to read Enomoto's lawsuit (pdf).

• Click here to visit FOXNews.com's Space Center.