CAPE CANAVERAL, Fla. -- The International Space Station may provide the setting for a 500-day pretend trip to Mars in another few years.

NASA said Tuesday that consideration is under way to use the space station as a dry run for a simulated trip to and from Mars.

It would be patterned after Russia's mock flight to Mars that lasted 520 days at a Moscow research center. Six men were involved in that study, which ended late last year. They were locked in a steel capsule.

NASA's space station program manager Mike Suffredini said before astronauts can fly beyond low-Earth orbit, they'll have to spend more than six months aloft at a time. That's the typical stint for space station crews. Five hundred days is more than 16 months.

The human endurance record of 14 months was set by a Russian cosmonaut aboard the Mir space station in the mid-1990s. Only two others - both Russians - have spent as long as a full year in space.

No NASA astronaut has spent more than seven months in space on a single mission.

Suffredini doesn't expect any such Mars simulation aboard the space station to occur any sooner than two to three years. Physical as well as psychological questions will have to be addressed before anything of that sort is attempted, he said.

Steps are under way, however, for such an effort, and scientists and flight surgeons already are working on it. The goal would be to have all the data in hand so the space station can be used as a Mars test bed before its projected demise in 2020 or thereafter.

Suffredini said he expects the consensus ultimately will be to simulate "at least the first leg of a trip to a distant planet."

NASA's future for manned exploration is up in the air as the debate drags on as to where astronauts should head in the decades ahead: the moon, asteroids and/or Mars. The cost promises to be a major factor, along with the development of rocketships big enough to travel so far.