The Impossible Voyage Home

Marlowe didn't need to glance at the charts; the curve was beginning to flatten. Mathematically, it was determinable when it wouldn't rise at all. According to analysis, Man someday might be able to endure the radiation encountered in space as long as three years, if exposure times were spaced at intervals. It always ended here—younger, tougher, the finest the race produced—and still not good enough. And after years of training, they had twenty-five months to function as spacemen. It was a precious thing, flight time, and each trip was as short as science could make it. Conjunction was the magic moment for those who went between the planets.