Thrillionaires: The New Space Capitalists

Paul G. Allen’s first foray into rocketry, as he recalls it, was inauspicious.

“My cousin and I tried to build a rocket out of an aluminum armchair leg,” he said. At just 12 years old, the future billionaire raided his chemistry set for zinc and sulfur, and packed the fuel mixture into the tube. He got the formula right, but had not looked up the melting point of aluminum.

“It made a great noise,” he said, “and then melted into place.”

His rockets have gotten better since then, and a lot bigger, too. Mr. Allen, who became a co-founder of Microsoft, is responsible for SpaceShipOne, the pint-size manned rocket that won the $10 million Ansari X Prize competition last year as the first privately financed craft to fly to the cusp of space – nearly 70 miles up.