Word: crewed
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Dates: during 1980-1989
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...after week, bearing construction modules and fuel supplies to a giant space station in earth orbit. There, skilled workers have been assembling the ship that will take the first humans to Mars. After more than a year of construction, the million- pound, ungainly looking spacecraft is ready. With a crew of eight, it separates from the space station and heads for Mars, following the Hohmann ellipse, a space trajectory that may one day be as familiar as a great-circle route over the North Atlantic...
Twenty days later, the blue-white earth has shrunk to a bright dot of light against the background of stars in the eternal night of outer space. Looking back, the crew members are filled with a sense of isolation, a feeling that will never quite leave them during the 280-day outbound leg of their journey. A busy schedule provides some distraction. The space travelers perform scientific experiments, practice taking shelter against solar-flare radiation, tend vegetables in their hydroponic greenhouses, exercise vigorously for several hours each day and tap into digital libraries for music, light reading matter and courses...
...they head farther into space, the time required for their radio signals to reach earth lengthens to minutes, and the ever widening gap between questions and answers makes conversation difficult. Now, with the earth more than 100 million miles away, Mars is looming in the spacecraft portholes, and the crew begins preparing for a yearlong adventure on another world...
...long the voyagers stay on Mars will depend in part on the homeward-bound route. To await the proper alignment of Mars and the earth for an economical Hohmann-ellipse return, the crew would have to remain on Mars for more than a year -- increasing the mission length to what now seems an unbearably long 1,100 days. But with the expenditure of more fuel, the explorers could blast off earlier, head toward Venus and loop around it, using the planet's gravity to whip their craft toward earth at a higher speed. That would cut the mission time...
...peak physical and mental condition. The medical consequences of long periods of weightlessness are still not fully understood. And radiation, says NASA's Michael Bungo, "is going to be a showstopper." Once beyond the earth's atmosphere and magnetic field, which protects terrestrial life from most lethal radiation, crew members would be vulnerable to cosmic rays. These highly energetic particles travel through space at close to the speed of light and can produce hazardous secondary radiation when they strike atoms in the aluminum walls of a spacecraft. During a single Mars mission, says Frank Sulzman, chief of NASA's space...