An American tycoon who offered the Russians $20 million if they'd fly him to the international space station will get his wish this weekend when he's rocketed into orbit on a dream-come-true adventure.

NASA officials are not pleased, but they agreed, reluctantly, to the trip after wringing a few concessions from the Russians: The high-flying tourist, Dennis Tito, a California engineer and financier, will be carefully supervised and generally restricted to the Russian side of the station. And if he breaks anything, he pays.

NASA had strenuously objected to the Russians independently selling a space station trip to Tito. But, in the end, the U.S. agreed, along with the other international space station partners, Japan, Canada, Russia and the European Space Agency.

Tito, chief executive at Wilshire Associates in Santa Monica, Calif., will fly with two cosmonauts aboard a Soyuz spacecraft scheduled to deliver supplies to the International Space Station, called Alpha.

Tito's visit is causing a scrambled work schedule for the crewmembers already aboard Alpha, according to a NASA task force headed by former astronaut Thomas Stafford.

Stafford said in a briefing Tuesday that the task force recommended that a number of experiments be shut down or not performed, and that testing work halt on the new mechanical arm installed this week on the space station. These changes are required, said Stafford, as "risk-mitigating actions" because of Tito's presence.

"There is no doubt that this will have an impact on the activity up there," Stafford said.

The task force recommended that Tito not be allowed aboard the American portion of the space station without an astronaut escort. The group also called for Tito to sleep in or near the Russian spacecraft, in the event of an emergency when he is asleep.

"It should be made clear to Mr. Tito that his activities are limited to the Russian modules, due to his lack of adequate training on the U.S. modules, unless escorted by an (astronaut)," said Stafford.

Stafford said that the Russian space agency also "must guarantee to all of the ISS partners that it is fully liable for the flying of Mr. Tito and that in the future this type of unilateral decision will never happen again."

Mike Hawes, a deputy associate administrator at NASA, said Tito has signed a U.S. agreement, called the Crew Code of Conduct, and a Russian flight rules statement that spell out his responsibilities and limitations as a crew member.

Hawes said Tito also has agreed to pay for anything he breaks during the mission and agreed to "hold harmless" the space station partners for anything that happens during the flight.

Tito is the first person to buy his way into space, but Hawes said he probably will not be the last.

"Tourists in space are inevitable," said Hawes, but the Russian agreement with Tito made it "earlier than we anticipated." He noted that NASA is prohibited now by administrative regulations from flying tourists.

Michael A. Greenfield, a NASA member of the Stafford task force, said members of the group were very concerned about the lack of training given to Tito and his ability to respond appropriately in an emergency. Greenfield said Tito received less training than what the Russians provided two other nonprofessional space fliers, a journalist and a food expert, that took trips earlier on Russian spacecraft.

Greenfield said that the Russians had originally agreed to not have a nonprofessional fly on Alpha until the space station assembly was complete, still several years away.

The Russian insistence on flying Tito, he said, "took us by surprise."

Tito accompanied his Soyuz crewmates to the Johnson Space Center last month to undergo training, but NASA officials refused to let him participate unless he agreed to certain conditions. The Russian cosmonauts then boycotted one day of training as a protest but later returned and completed the exercises without Tito.

Tito originally was scheduled to fly to the Russian space station Mir. After that orbiting lab was decommissioned and eventually dumped in the Pacific Ocean, Tito's ticket to space was shifted to the ISS.