Fit, and on a Mission
Can the human body survive a lengthy Martian sojourn?
'They are huge!" exclaimed astronaut turned construction worker Joseph Tanner last week from a zero-gravity perch more than 200 miles above Earth's clouds. With millions of people sharing their views--via helmet-mounted cameras feeding ground control, the Internet, and TV networks--he and fellow NASA spacewalker Carlos Noriega had just attached a folded set of solar panels to the growing International Space Station and were watching a portion slowly stretch itself out from accordion-style stowage. Told that the electricity-generating expanse of gleaming silicon was only two-thirds extended, he could only marvel, "You mean there's more?"
There will indeed be lots more. The new solar panels span 240 feet, but when done the million-pound facility will stretch 356 feet. Astronauts on future flights must install three more sets of panels, six large laboratories, extensive trusswork, and living accommodations for crews of seven people at a time. Its first three modules have made up the spartan residence for American commander William Shepherd and Russian cosmonauts Yuri Gidzenko and Sergei Krikalev since early November. The shuttle Endeavour and its five crew members arrived last week with the new panels plus water and other basics. In February, the shuttle Discovery is to bring the first crew home and leave a second trio for the next four-month shift.
And so it will go for another five-plus years. It is a dazzling project, but sheer spectacle cannot stop some taxpayers from wondering what, exactly, this multibillion-dollar labyrinth of airtight corridors, cylinders, and gleaming, custom-designed research facilities is for. While scientists from 16 nations will pursue a variety of research projects, biomedical researchers are mostly interested in the bones, muscles, and organs of the station's long-term residents.
Feeble and flabby. For while Tanner and Noriega labored through three spacewalks--and just moving one's arms in a spacesuit inflated like a balloon is not easy--their muscles were steadily, slowly growing feebler, their bones flimsier, and their hearts flabbier. For billions of years, life on Earth has evolved to thrive in a steady gravitational field. Scientists are not surprised that from the cellular level up, things start going haywire without gravity. Brief shuttle flights pose few health threats, but cosmonauts and the several NASA astronauts who have spent months aboard the smaller, soon-to-be scuttled Russian space station Mir returned so weak they could barely stand. After floating freely, many wanted nothing more than the nearest, softest easy chair when they got back.
And the underlying motive for controlling the slow debilitation of the human body in very low gravity can be summarized in one word: Mars. NASA has not formally proposed a Red Planet expedition, but Administrator Dan Goldin recently declared flatly that the station gives the means to "ensure the continued health and safety of our astronauts, so that they will be able to leave low-Earth orbit to travel to Mars or beyond." It will be a long trip. NASA estimates it will take six months just to get people to Mars. They then might spend a year and a half in Martian gravity--38 percent of Earth's--and six months getting back. Without measures to counteract the effects of weightlessness, some experts fear the voyagers could die or never recover from debilitation once home.
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