Many people on Earth would have been excited by the chance to work for two years with Professor Glover on the ten-thousand-billion-volt proton synchrotron which they called the Lunatron. Most physicists thought they were lucky if they could spend a few months with the fifty-billion-volt antique at Brookhaven. But at Brookhaven you are only a few minutes from New York. Up on the space laboratory Britten was a year from any place, and every day that went by made it a day less. "Johnny, what's the first thing you're going to do when you get back to Rhodesia?" he asked his roommate. Britten sat, twanging half-heartedly at his guitar, while Johnny lay undressed on his bunk, his body hard and black against the white sheet. "Oh, I have a good job lined up in a brand new research institute in Salisbury." "I don't mean that," Britten said, impatiently. Johnny was such a serious boy. "I mean don't you think of all the fun you're going to have when you get back to Earth? Don't you think of getting a girl friend and living like everybody else lives?" But Johnny's deep brown eyes remained serious, and he said, "Coming up here has been a great opportunity to learn something so that I will be able to do good work when I get back. Everybody down there does not get such a chance." Well, Britten thought, that's how it had been with him at first. Now he could think of nothing but walking arm in arm with a pretty girl—his girl—down the street of a big city at night, drinking in the excitement, the feeling of being with other people among the bright lights, under a sky that would be dark blue instead of black, that might have clouds in it, that might even send down rain, instead of being the stark changeless interstellar space that existed up above. Scientists aren't supposed to have thoughts like these. But Britten was young, he was homesick, and he was bored. A young, homesick scientist cannot remain a solemn, dedicated, single-minded scientist. The next day at work he absentmindedly switched on some pieces of apparatus in the wrong order and burned out a minor piece of electronics. "Damn it, Britten," Professor Glover shouted at him. "Where are your brains? Replacements are expensive up here. Time is expensive!" Britten began shaking with rage. Words rushed to his tongue which he choked down