The soldiers fell silent awhile. Robin turned these words over carefully. He had read nothing of any Red Sands operation, and he remembered nothing of any talk about atomic fuels. In fact he'd understood that the problem was still one they had failed to solve--though the idea was intriguing. Chemical fuels, he knew, had definitely limited drive capacities. The most powerful chemical fuels possible even theoretically were those already in use, and were basically merely liquid oxygen and liquid hydrogen. And he knew that the main obstacle that always had to be faced by rocket engineers was the tremendous quantities and weights of the fuels to be burned in order to lift even a single pound of cargo. Atomic power, if liberated, had on the other hand almost unlimited possibilities as fuel. A mere pound or so of atomically liberated material could probably drive a spaceship a million miles with a full pay load too. But how to combine atomic explosions with controlled rocket fire? The problem had never been answered--at least not in the magazine and newspaper stories he had ever read. He thought about it awhile. Then the bus honked its horn. Robin craned his neck, looked forward. He saw they were paralleling a high wire fence and coming to a lighted area. A large sign on a wide road entrance branching off caught his eye and he read the magic words, _White Sands_. For a moment he thought the bus was going to enter as the driver slowed down. They came abreast of the gateway but the driver merely honked and waved and passed it by, Robin catching a glimpse of whitewashed barracks and low hangarlike structures beyond the gate. Then they roared on into the moonlit night, on toward the empty reaches of the desert where the mountains loomed dark in the horizon. Where was Red Sands? How far? Robin speculated on it. He had evidently hit on something more than he'd reckoned. This was a development unknown to the public. This was something that must have combined the special nature of the Los Alamos atomic testing grounds with the rocket grounds. And it was obviously tucked far away from them all. Suppose they caught him there, would he get off as lightly as he might at White Sands? Where atomics was concerned, secrecy was still enforced, despite the release of much information due to the installation of peaceful atomic plants in various parts of the world. But everyone knew that the world was still merely at the threshold of atomic glories and the nations were still anxiously vying with each other for leadership. He supposed that perhaps he might be sent to jail. He might perhaps be confined to the Red Sands grounds until such time as what he was to learn had become public property. That might take years! Robin squirmed a little as he thought over this possibility. It didn't appeal to him. Yet, the die was cast and there was now little he could do about it.