There was a small bright sliver of sunlight high aloft. It moved slowly toward the east. It showed the unmistakable glint of sunshine upon polished steel. It was the artificial satellite--a huge steel hull--which had been built in the gigantic Shed from whose shadow Joe looked upward. It was the size of an ocean liner, and six weeks since some hundreds of pushpots, all straining at once, had gotten it out of the Shed and panted toward the sky with it. They'd gotten it twelve miles high and speeding eastward at the ultimate speed they could manage. They'd fired jato rockets, all at once, and so pushed its speed up to the preposterous. Then they'd dropped away and the giant steel thing had fired its own rockets--which made mile-long flames--and swept on out to emptiness. Before its rockets were consumed it was in an orbit 4,000 miles above the Earth's surface, and it hurtled through space at something over 12,000 miles an hour. It circled the Earth in exactly four hours, fourteen minutes, and twenty-two seconds. And it would continue its circling forever, needing no fuel and never descending. It was a second moon for the planet Earth. But it could be destroyed. Joe watched hungrily as it went on to meet the sun. Smoothly, unhurriedly, serenely, the remote and twinkling speck floated on out of sight. And then Joe went back to the table and ate his breakfast quickly. He wolfed it. He had an appointment to meet that minute speck some 4,000 miles out in space. His appointment was for a very few hours hence. He'd been training for just this morning's effort since before the Platform's launching. There was a great box swinging in twenty-foot gimbal rings over in the Shed. There were motors and projectors and over two thousand vacuum tubes, relays and electronic units. It was a space flight simulator--a descendant of the Link trainer which once taught plane pilots how to fly. But this offered the problems and the sensations of rocketship control, and for many hours every day Joe and the three members of his crew had labored in it. The simulator duplicated every sight and sound and feeling--all but heavy acceleration--to be experienced in the take-off of a rocketship to space. The similitude of flight was utterly convincing. Sometimes it was appallingly so when emergencies and catastrophes and calamities were staged in horrifying detail for them to learn to respond to. In six weeks they'd learned how to handle a spaceship so far as anybody could learn on solid ground--if the simulator was correctly built. Nobody could be sure about that. But it was the best training that could be devised.