(Time passed after Ed McCauley became Major Ed McCauley, and most people forgot him. If his name was mentioned, someone might say vaguely: "McCauley ... McCauley? It seems to me I've heard the name." This was because remarkable events don't stay remarkable as time goes past. There was a two-hundred-pound satellite circling the moon these days, industriously sending back not only pictures of the moon's far side, but pictures of cloud masses on Earth which told much more about Earth's weather than had been known before. A drone missile had gone out to Mars, and its instruments suggested that men had better not come out just yet, and other drones had gone past Venus and said definitely that men better not come out just yet. So something had to be done to make those journeys possible. Men had to work in space, testing this and trying that, staying days or weeks at a time when solar flare-particles were not too much in evidence. This meant that there had to be a place for them to live and work. There were plenty of men who'd done spectacular things lately, but this needed somebody who would be worrying not about fame, but about getting a job done right. So Major McCauley received certain orders.) On as much of the Space Platform as existed so far, a working day lasted an hour and forty minutes. There wasn't much of the Platform, as yet. The greatest bulk was a squat, clumsy metal object which had come up from Earth, pouring out rocket flames, to be the Platform's nucleus. From it now sprouted spidery, flimsy metal girders which reached out in apparent aimlessness. They formed an incomplete skeleton of joined triangles whose final form seemed indefinite. But in time they would form a most unlikely icosahedron traced in threads of silvery metal in emptiness. Although the Platform was barely begun, it grew noticeably as time went by, even though the working day was so brief. Some people would have challenged the word "day." There was no true night where the first part of the Platform floated hurriedly in orbit some three thousand miles out from the planet Earth. There was light when the sun shone on it, which was two hours and five minutes out of three hours and seven. Despite Luna, Earth's ancient and untidy moon, there was abysmal darkness when the Platform plunged into Earth's shadow. This was not nightfall. When sunlight ended, cut off by Earth's eight-thousand-mile bulk of stone and metal, the phenomenon was an eclipse. Once in each revolution about the world which was building it, the Platform was eclipsed by Earth. When light returned, it was not sunrise, it was the ending of an eclipse.