NASA and its partners in the international space station have drafted a proposal to clear California millionaire Dennis Tito for a late April flight to the orbiting complex, but only as an exception, a NASA official said Friday.

The space agencies have yet to approve the proposal but were expected to on Monday, said the official, who insisted on anonymity. The general attitude is, "OK, we'll let it happen this time," said the official.

The proposal is the result of weeklong meetings in Moscow between U.S. and Russian space officials on the subject.

If all goes as he hopes, Tito will become the world's first space tourist when a Soyuz rocket blasts off from Kazakstan on April 28. He is paying as much as $20 million to Russian space officials for the launch and almost a week aboard the space station.

For months, NASA has opposed Tito's space station visit on safety grounds. The space agency softened its rhetoric during the past week, saying it wanted to ensure that Tito, if he flew, would not jeopardize anyone's safety aboard the space station or disrupt the crew's work.

Already, flight controllers are looking at ways to rearrange the space station crew's jobs, if necessary because of Tito's presence. Space shuttle Endeavour's astronauts are bringing a new, enormous robot arm to the space station; they will install it during the next several days, but it will be left to the space station crew to practice using it.

Tito, 60, an aerospace engineer-turned-financier has been training for months at cosmonaut headquarters in Star City, Russia. He was supposed to fly to Mir, but switched his ticket to the international space station once the Russian government decided to dump Mir.

That's when NASA — and the European, Canadian and Japanese space agencies — began expressing dismay.

"The concerns about safety, training, liability are still there," NASA spokesman Bob Jacobs said late Friday afternoon from the agency's headquarters in Washington. "But those issues are being worked even at this very moment. During this past week, we've had a team in Russia working daily with the Russian Space Agency trying to resolve it."

Space station Alpha's Russian commander, Yuri Usachev, and his two U.S. crewmates, Jim Voss and Susan Helms, have said repeatedly they will welcome whoever arrives in the Soyuz.

A fresh Soyuz spacecraft is needed to replace the one that has been docked at the space station since the beginning of November. The three-person Soyuz serves as a lifeboat.

The Soyuz will lift off the same day that Endeavour undocks from the space station, and will arrive at the orbiting complex two days later, on April 30. Tito and his two Russian crewmates will spend about six days there and return to Earth in the old Soyuz in May.