HOUSTON A crucial set of ground rules may be in place in time to clear U.S. millionaire Dennis Tito for a controversial tourist flight to NASAs International Space Station (ISS) in late April.

Thats the word at Johnson Space Center as NASA officials and their Russian counterparts meet this week to develop a wide-ranging set of criteria for vetting civilians -- and not Tito specifically -- intent on paying for round-trip excursions to the outpost.[uplink]

"Were totally supportive of flying civilians in space," former NASA chief astronaut Robert Cabana, who now is the agencys senior station project manager for international operations, told SPACE.com during a news briefing Wednesday. "We just want to make sure that when we do, we have agreed upon criteria for integrating those people into the [station] crews, and that all the international partners agree, and that were doing it safely, and in the best interest of the International Space Station program."

The so-called Bilateral Crew Operations Panel took up the topic Tuesday and is discussing the type of preflight training and medical tests a prospective civilian flyer would have to successfully complete before launching to the station.

The panel chaired by NASA chief astronaut Charlie Precourt and including veteran Russian cosmonaut Vasily Tsibliev will form recommendations that then will be passed along to project managers on the U.S. and Russian sides.

Ultimately, all ISS partners including the European Space Agency, whose chief project manager recently voiced strong opposition to a Tito flight to the station would weigh in on the screening criteria.

Cabana indicated that establishing the criteria and then getting all ISS partners to agree upon the ground rules could become a lengthy process. No firm decisions, consequently, are expected at the conclusion of the panels meetings this week.

"The key here is to come up with a set of criteria that everybody can buy in to," the veteran shuttle mission commander said. "We want to ensure that were flying safely, that our crews are assigned properly, that theyre trained properly and that they work well together onboard the International Space Station."

Still unclear, however, is whether that process will come to closure before the anticipated flight of Tito, who already has completed four months of training in Russia and also has passed rigorous cosmonaut medical tests.

A wealthy investment manager from California, Tito, 60, signed a contract in January with the Russian Aviation and Space Agency, also known as Rosaviacosmos, to make a 10-day round trip to the international station aboard a Soyuz "taxi" flight set for launch April 30.

The former NASA engineer who once designed flight trajectories for planetary exploration missions to Mars and Venus agreed to pay Rosaviacosmos and other Russian aerospace entities an estimated $12 million to $20 million for the flight.

The deal, however, has sparked a highly charged controversy, with opposition coming from senior NASA managers, much of the agencys astronaut corps, members of Congress and European space station officials.

"Whatever we do, itll be a joint decision among all the partners and we will agree that what we are doing is safe and in the best interest of the program," said Cabana. "And whether thats April or later or whenever, I think that well have agreement on it."

The joint U.S.-Russian crew that will be onboard the station in late April, meanwhile, is largely sitting on the sidelines, watching the process -- and the resulting controversy -- unfold.

Veteran Russian cosmonaut Yuri Usachev and two NASA astronauts Susan Helms and James Voss now are scheduled to launch to the station a week from today and will remain on the outpost for more than four months.

"The decisions on these types of things are made at a much different level than where we are. And weve been focused on our mission specifically -- and not necessarily who specifically is going to visit us while were up there," said Voss.

"I dont think that its up to us, and I dont think that I personally have too much of an opinion other than I think that whoever comes up needs to be properly trained," Voss added.

"It would be good if they had some time working with us so that we will know them, if theyre going to be living and working on the station with us for a while. Other than that, well welcome and will treat anyone the same that comes up to visit us."