But he must still drift and he knew now that he had started to fall. Ever so slightly, but he was heading straight for the great mass of Jupiter, and his initial direction had been almost tangent to its orbit. The massive orb seemed even more flattened at its poles than usual, and its satellites were orbiting erratically, due, he knew, to the Geejay failure that had rocked the whole system. Yet even as he watched, and as slowly as they swung, Jon Kane's practiced eye and mind detected retrograde movements, and realized that the tiny moons were slowly falling back in what he knew were approximately their former orbits. The Tinkers were somehow succeeding. But the suit was getting cold. Its insulation was surprisingly efficient, but it was still only an emergency feature of the rig, to keep a man alive for a short period in the event of heater failure. And using the heater meant radiation, yet he'd have to risk it now. And soon, the pack itself. But it would be of little avail if he wandered aimlessly, and that, he had to gamble, was where the numbers came in. With the three letter combinations, they could be spherical co-ordinates. For his life, they would have to be. 69-X. .01-Y. 86-Z. With planes of reference calculated to the median plane of planetary ecliptics relative to the Sun. Then. Swiftly, his brain analyzed the values, gave him an approximation. And it would be a point-- And where he looked there was only blackness. It was the damn time factor, of course, that was lacking. Yet Zetterman would not have given him figures for yesterday or next month. They'd have to be figures for now, or for expected time of arrival at destination, but where? How far? Near Jove? The satellites? One of them? That would make the time factor next to zero. And-- Of course! The figures would no longer be completely valid; margin of error would be wide after the gravitational imbalance that was only now beginning to be righted! If he scanned several hundred thousand miles to either side of his point of dead reckoning. And there it was! Callisto. He was almost astride its orbit, and because it was nearer to his reckoned point than any of the rest, it would have to be the most probable destination. If, of course, he was right about the time factor. If the co-ordinates referred to the location of bodies in the ship's immediate vicinity when it was attacked. He was numb from the cold, and to wait longer with his powerpack would mean to become ensnared in Jove's awful gravity field before he could make the necessary right angle break in direction and set course for the barren planetoid. His arms ached as he drew them up inside his suit, and his fingers were clumsy, senseless things groping for the power and heat toggles. Then he found them. In moments there was warmth, and then the gray satellite toward which he headed began getting larger with each passing second. * * * * *