But they are not harmless to the crew of a ship in space, or to the staff of that combined way station and observatory which is the Space Platform, or to the occupants of the bases on the moon. The Space Platform itself was set in orbit only three thousand miles out from Earth because of the Van Allen belts of just such particles that have been swung into paths around the earth and form invisible rings more or less resembling the visible rings of Saturn. At three thousand miles out these particles are not deadly. Farther out they are. It was not until the Bramwell-Faraday screen was devised that it became possible for a man to land upon the moon. With the screen, a man could survive passing through the Van Allen belts in screened ships and set up moon bases. But the margin of safety was not great. It was enough, but barely so. The Venus shoot was planned because this state of affairs would not last. Astrophysicists had developed a system for predicting solar flares. Then they'd found evidence and, later, proof that the flare frequency was due for an enormous and probably permanent rise. Dense clouds of flare particles would be released. The Van Allen bands would be intensified. Within a year, any man who went beyond Earth's protecting atmosphere could expect to get a fatal dose of radiation burns within an hour's exposure, a flare particle being "radiation" in the same sense as the particles thrown off by radioactive materials. The Bramwell-Faraday screen had to be improved, or else. And the only way to know that it was improved was to try it against stronger and stronger streams of the deadly particles until it failed--or worked. Which meant that somebody had to go out to where flare particles were abundant. So McCauley labored on the ship that was already nearly set to dive sunward. It would be equipped with the screen that had made Earth-moon travel possible. It would have on board Bramwell, who'd designed the screen to begin with. It would plunge into flare-particle radiation of such intensity that the ship's crew _might_ survive--with the present screen on full--but this was by no means certain. The ship would dive sunward to Venus, swing around that planet, and drift back out to the orbit of Earth. On the way, Bramwell would try to adapt his screen to protect the ship and himself in it. It was a highly melodramatic proceeding, and Bramwell looked very heroic. But he was a most unpleasant man. Having met him, McCauley estimated his personal attractiveness as much less than one-tenth the personal charm of an irritated skunk. * * * * * Ten days after his assignment to the Venus shoot, Randy came to McCauley with a sort of grim humor in his expression. "I took Bramwell over the ship," he said. "Since he's going to live and work in it, he thought he ought to see it." "That's reasonable," admitted McCauley. Randy held up his hand and ticked off on his fingers.