Lucid's Long Road Home

IT'S NOT THAT SHANNON LUCID WAS getting cabin fever. True, the 53-year-old astronaut had been hitting the M&M's, potato chips and other goodies pretty hard. But that was because regular food often tastes odd in zero gravity (for reasons scientists can't explain), not because spending six months aboard the Russian space station Mir with two cosmonauts had given her the stress-induced munchies.

And it's not like she was losing patience, exactly. Yes, the space shuttle that was originally supposed to bring her home got yanked from the launch pad in August when NASA suspected a problem with its booster rockets. Then her return was postponed again when Hurricane Fran forced Atlantis back into the hangar. But the delays landed Lucid--a biochemist, the mother of three grown children and a veteran of four previous space missions--in the record book: she had already broken the American space endurance record in July, and on Sept. 7 she took the women's world record with 169 days (the men's record is 439 days, held by a cosmonaut). Still, when the space shuttle Atlantis finally blasted off from Cape Canaveral last week for its rendezvous with Mir, Lucid wanted to make her wishes clear. So she asked mission control in Houston to radio up a special song to the six-man crew: the 1965 Fontella Bass hit ""Rescue Me.''

Atlantis is scheduled to finish that job later this week. After a postcard-perfect docking three days into the shuttle's flight, Atlantis and the silver-and-white Mir remained docked for five days, orbiting 240 miles above Earth while the crews exchanged cargo. About 2,200 pounds of broken equipment, scientific samples--and a very eager Lucid--floated through the docking tunnel from Mir to Atlantis. Some 4,600 pounds of equipment, garlic, onions, cucumbers, oranges (requested by the cosmonauts), fresh air and astronaut John Blaha moved to Mir. But when Lucid lands this Thursday, her rescue will not be over: she will be lifted out of Atlantis on a recumbent chair.

Spending six months in zero g brings one beneficial effect, Lucid deadpanned in an interview from space. She described herself as younger-looking, since gravity hadn't been pulling on her face muscles. After that, it's all downhill. Lucid may have lost as much as 25 to 30 percent of the mass in such extensor muscles as the calves and thighs, says physiologist Kenneth Baldwin of the University of California, Irvine, who chairs a NASA panel looking for ways to minimize the biological damage from spaceflight. Cardiac muscle also atrophies: with each beat, Lucid's heart pumps less blood, which will put a crimp in her plan to Rollerblade with her daughter and ride her bike to celebrate her return to terra firma. Within a few weeks rehab exercises should restore most of the lost muscle, however, just as it does for someone who has been confined to a wheelchair. But Lucid has also lost calcium from her bones. Everyone who travels into space loses about 1 percent of bone mass every month without gravity. If Lucid is postmenopausal (NASA doesn't ask and doesn't tell), she could have lost an additional .5 percent a month unless she is on estrogen-replacement therapy. That calcium might be truly lost in space. ""There is some evidence that the bone loss cannot be reversed,'' says osteo-researcher Christine Snow of Oregon State University.

Just as a sailor returning to port wonders why the land won't stop rolling, Lucid's sense of balance will likely be off for a while. She may have trouble coordinating her steps and even holding her head up. In orbit, explains physiologist Reggie Edgerton of UCLA, the nervous system continuously activates the flexor muscles in the knees and elbows, to bring all parts of the body closer to the center of mass. That seems to make moving in zero gravity easier. But the extensors, which work against gravity to hold the body erect, fall into disuse. As a result, the junctions where nerves fire to move muscles become stronger at the flexors and weaker at the extensors. It takes time to restore the balance, and until then Lucid may have great difficulty walking. Her hand-eye coordination will also become shaky, possibly for a period as long as six months, says Baldwin. After 45.5 million miles in orbit, she can also expect to black out, or at least feel dizzy, whenever she stands up, due to a sharp drop in blood pressure that is caused by prolonged zero g. Because of these ill effects, any mission of more than six months--a flight to Mars, say--will require artificial gravity.

No shower: What Lucid won't suffer, NASA believes, is psychological after-effects. Ever since Mir's 40-foot-long core was launched, in 1986, the Russians have tried to give it all the comforts of a little dacha in the sky. With dark green carpeting, light green walls and a white ceiling, the ""operations area'' (diagram) is cool and visually soothing. The private crew cabins have a porthole, hinged chairs and a sleeping bag. Behind a curtain are a shared suction-operated toilet, sink and place for sponge baths (no shower). Each crew member has ample privacy, says former astronaut Norman Thagard, the only other American to live on Mir: ""We could go for long periods of time without seeing each other.'' Still, it's not for everyone. Astronauts have to ace psychological tests of self-sufficiency, patience and ability to tolerate isolation. Beyond that, those with a ticket for Mir go through training developed by the Russians, which emphasizes coping with anything, from danger to boredom, that space might throw at them. ""For flights out to six months,'' says Thagard, ""there are no problems except, potentially, crew compatibility. Longer than that, we don't know.'' But he suspects that the problems would be fewer on a flight to Mars, ""because it would be more goal-oriented. That's a lot different than orbiting the Earth over and over.'' Or, in Lucid's case, over and over and over and...

Though American astronaut Shannon Lucid wasn't exactly living in luxury for the past six months, the Russian space-station Mir is not as claustrophobic as you might think. It consists of seven modules brought together over 10 years, and has more than 13,000 cubic feet of habitable space.

Core module: Mir's central compartment has a maximum diameter of 13.5 feet and a length of 43.3 feet. It has a kitchen, exercise bike and private crew cabins.

Kvant 2: Contains life-support equipment, solar arrays and a new bathroom, which replaced one in the core module. It has a privacy curtain and a suction toilet.

Spektr: Lucid slept in this 43-foot-long module, apart from the cosmonauts. It's used for atmospheric research and monitoring background radiation

Source: NASA, AP. Research by Brad Stone. Graphic by Dixon Rohr and Christoph Blumrich