WASHINGTON -- NASA and Russian study groups are meeting this week to hammer out issues surrounding the possible flight of U.S. millionaire Dennis Tito to the International Space Station.

The Dennis Tito Story

Russians Refuse NASA Training Without Tito An international incident cropped up at Johnson Space Center Monday when Russian cosmonauts headed for the ISS in April refused to begin training after fellow crewman Dennis Tito was excluded from the exercises.

Cosmonauts Told to Resume Training, Station"s First Skipper Comments New marching orders to cooperate and resume work are on their way thismorning from Moscow to the Russian cosmonauts in Houston who staged a Texas standoff with NASA officials on Monday.

Canadian Space Agency Says Tito Needs More than Money to Visit ISS The Canadian Space Agency opposes Dennis Tito"s trip to the ISS, as SPACE.com learned during a conversation with Canadian astronaut Marc Garneau.

In a March 22 phone conversation, NASA chief Daniel Goldin spoke with Yuri Koptev, head of Rosaviacosmos, the Russian space agency, on the Tito matter. The two agreed on issues that need resolution concerning the flight of Tito, said Kirsten Williams, a NASA spokeswoman.

"There is a whole list of things that they agreed to do. They agreed to talk again once some of these things are done," she told SPACE.com.

David Drachlis, a NASA spokesman, said that discussions are continuing between NASA and the International Space Station partners, including Rosaviacosmos, concerning the Russian proposal to fly Tito to the station in April.

During a news conference on Wednesday, NASA scientists said the launch date had been moved up two days, to April 28.

Upon completion of the assessment, there will be presentations to both NASA and Rosaviacosmos, Drachlis said. No date has been set, but Goldin and Koptev are expected to discuss the group's recommendations.

NASA and Rosaviacosmos have agreed to a series of steps that help evaluate safety considerations associated with Titos proposed flight, Drachlis told SPACE.com.

The specific steps include a joint safety assessment by a NASA Advisory Council Task Force on International Space Station Operational Readiness. Former Gemini, Apollo and Apollo-Soyuz Test Project astronaut, Thomas Stafford, leads that task force.

Staffords task group will be working with an advisory expert council in Russia, which is delving into Tito flight issues.

The council and Stafford will assess the safety and operational issues associated with flying a non-professional astronaut/cosmonaut to the International Space Station during the upcoming April Soyuz taxi flight, Drachlis said.

The two groups are meeting this week in Russia, Drachlis said.