Alpha astronauts: Trip to Mars is doable

Susan Helms, left, Yury Usachev, center, and Jim Voss lived on the space station more than five months.

ATLANTA, Georgia (CNN) -- Astronauts should have little trouble adapting to Mars after a long flight in zero gravity, said departing residents of the international space station in a live interview with CNN.

After more than five months and 2,500 sunsets in orbit, the second space station crew is scheduled to return home on space shuttle Discovery on Wednesday.

Taking their final laps around the planet, the three took part in a long distance conference call with CNN Space Correspondent Miles O'Brien on Tuesday.

Noting that the duration of their flight was similar to the time necessary to send a manned mission to Mars, O'Brien wondered if humans arriving at the red planet would "be able to do any useful work" or "stand up in the one-third gravity of Mars?"

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Certainly, if the crew worked out with specialized exercise equipment, like that onboard space station Alpha, said Jim Voss, who spent 5 1/2 months on the orbiting outpost, along with fellow NASA astronaut Susan Helms and Russian Cosmonaut Yury Usachev.

"We have a pretty good program for keeping ourselves in good shape. We have two bicycles, a treadmill and an exercise device that simulates weightlifting," Voss said.

"I think the same thing would be true of going to Mars. As long as people worked very hard, they would be in reasonably good shape and they would quickly recover, especially with a little bit of lighter gravity there."

Despite the exercise regimen, which lasted at least an hour each day, the old Alpha crew can expect weeks of physical therapy to regain muscle and bone strength lost during the flight, the second longest in NASA history.

Usachev could have an easier time recovering, having spent two long-duration missions on the retired Russian space station Mir.

Pining for beach smells

As far as adjusting, when they began their trip from normal gravity to the weightlessness of space, Helms said it was a breeze:

"We definitely became accustomed to the space environment very quickly. And after five and one-half months, it seems completely natural."

Space station Alpha

But there is much that Helms longs for on the ground: family, friends, bandmates in an all-astronaut rock band, and even simple, everyday sensations.

"I think we have all missed certain smells, such as the smell of the beach and pine trees. We have a very sterile environment on the space station and you just don't get the variety that you get on Earth, as far as the different smells of nature," she said.

Helms should have a chance to breathe in ocean air soon. The shuttle Discovery is scheduled to land at 12:46 p.m. EDT Wednesday at Kennedy Space Center in Florida, which borders miles of surf on the Atlantic Ocean.

Discovery deposited the third Alpha crew on the space station last week. U.S. skipper Frank Culbertson and Russians Vladimir Dezhurov and Mikhail Tyurin will spend four months aboard the modular complex.