ONCE UPON a time there was a Martian named Valentine Michael Smith. The first human expedition to Mars was selected on the theory that the greatest danger to man was man himself. At that time, eight Terran years after the founding of the first human colony on Luna, an interplanetary trip made by humans had to be made in free-fall orbits—from Terra to Mars, two hundred-fifty-eight Terran days, the same for return, plus four hundred fifty-five days waiting at Mars while the planets crawled back into positions for the return orbit.
