Baikonur, Kazakhstan ? U.S millionaire scientist Gregory Olsen, the world’s third space tourist, bid farewell to his family Friday during final preparations for his flight to the international space station with a Russian-American crew.

The 60-year-old founder of an infrared-camera maker based in Princeton, N.J., reportedly paid $20 million for a seat today on the Expedition 12 flight.

Olsen, who holds advanced degrees in physics and materials science, defended his presence in the capsule as a necessary step in the evolution of space travel.

“I would hope that my flight would help, if just to make space flight more routine,” Olsen said in a telephone interview with The Associated Press.

“One hundred years ago, airline flight was reserved for only a few brave souls. Everyone flies (on planes) nowadays. The same will be true of space flight.”

With the Russian-built Soyuz rocket being fueled on the launch pad Friday in Kazakhstan’s barren steppes, Russian and American officials held tough talks on the future of joint space missions, with NASA’s chief warning that Moscow’s demands for payment could end U.S participation.

NASA Administrator Michael Griffin said a 2000 U.S. law banning space station-related payments to Russia because Moscow helped Iran build a nuclear plant “could end a continuous American presence” on the station.

The cash-strapped Russian Federal Space Agency has turned to space tourism to generate money. Olsen is the third non-astronaut to visit the station: California businessman Dennis Tito paid about $20 million for a weeklong trip to the space station in 2001, and South African Mark Shuttleworth followed a year later.

Olsen made his fortune on optic inventions. He is the co-founder of Sensors Unlimited Inc., a company that makes infrared imaging cameras and fiber-optic communications components.

Asked by a reporter how his health was, Olsen replied, “This has been two years of very hard work. In 20 hours, I will feel very, very good.”