BAIKONUR, Kazakhstan (AP) – Engineers made final preparations Thursday for the weekend launch of a Soyuz spacecraft to the international space station, with a U.S. scientist who paid $20 million for the journey among those aboard.

Cosmonaut Valery Tokarev and U.S. astronaut William McArthur are scheduled to blast off from the Baikonur Cosmodrome Saturday and dock with the orbiting station two days later.

Joining Tokarev and McArthur will be their paying passenger, Gregory Olsen, who will be the third non-astronaut to visit the station.

Tokarev and McArthur will replace Russian Sergei Krikalev and American John Phillips, who have been in orbit since April. Olsen will return to Earth on Oct. 11 along with Krikalev and Phillips.

At dawn, engineers began moving the 30-ton, 164-foot Soyuz rocket by rail to the launch pad. After the roughly two-hour journey, workers set the rocket and its Soyuz TMA-7 capsule upright, and began connecting and checking electrical and mechanical systems. Fueling will take place Friday.

On Thursday, Tokarev, McArthur and Olsen met with doctors, reviewed flight plans and conducted computer simulations for operating the Soyuz capsule, said Maxim Kharlamov, a Russian space official helping in preparations for the three men.

Russia's workhorse Soyuz and Progress spacecraft have regularly shuttled crews and cargo to the space station, serving as the station's lifeline after the 2003 Columbia disaster grounded the U.S. shuttle fleet until earlier this year. The shuttle Discovery visited the station in July, but problems with the foam insulation on its external fuel tank have cast doubt on when the shuttles will again be able to service the station.

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