They were very near the Platform. And it was very near to completion. Joe looked at it hungrily, and he felt a great sense of urgency. He tried to strip away the scaffolding in his mind and see it floating proudly free in emptiness, with white–hot sunshine glinting from it, and only a background of unwinking stars.
Sally's voice went on: "And I've really put up an argument about the living quarters. They had every interior wall painted aluminum! I argued that in space or out of it, where people have to live, it's housekeeping. This is going to be their home. And they ought to feel human in it!"
They passed into one of the openings in the maze of uprights. All about them there were trucks, and puffing engines, and hoists. Joe dragged Sally aside as a monstrous truck–and–trailer came from where it had delivered some gigantic item of interior use. It rumbled past them, and she led the way to a flight of temporary wooden stairs with two security guards at the bottom. Sally talked severely to them, and they grinned and waved for Joe to go ahead. He went up the steps—which would be pulled down before the Platform's launching—and went actually inside the Space Platform for the first time.
It was a moment of extreme vividness for him. Within the past hour he'd come to think detachedly of the possibility of death for himself, and then had learned that he would live for a while yet. He knew that Sally had been scared on his account, and that her matter–of–fact manner was partly assumed. She was at least as much wrought up as he was.
And this was the first time he was going into what would be the first space ship ever to leave the Earth on a non–return journey.
7
Nobody could have gone through the changes of emotion Joe had experienced that morning and remained quite matter–of–fact. Seeing a dead man who had more or less deliberately killed himself so that he wouldn't have to kill Joe—for one—had its effect. Knowing that it was certainly possible the man hadn't killed himself in time had another. Being checked over for radiation burns which would mean that he'd die quite comfortably within three or four days, and then learning that no burns existed, was something of an ordeal. And Sally—of course her feelings shouldn't have been as vivid as his own, but the fact that she'd been scared for him held some significance. When, on top of all the rest, he went into the Space Platform for the first time, Joe was definitely keyed up.
But he talked technology. He examined the inner skin and its lining before going beyond the temporary entrance. The plating of the Platform was actually double. The outer layer was a meteor–bumper against which particles of cosmic dust would strike and explode without damage to the inner skin. They could even penetrate it without causing a leak of air. Inside the inner skin there was a layer of glass wool for heat insulation. Inside the glass wool was a layer of material serving exactly the function of the coating of a bulletproof gasoline tank. No meteor under a quarter–inch size could hope to make a puncture, even at the forty–five–mile–per–second speed that is the theoretical maximum for meteors. And if one did, the selfsealing stuff would stop the leak immediately. Joe could explain the protection of the metal skins. He did.
"When a missile travels fast enough," he said absorbedly, "it stops acquiring extra puncturing ability. Over a mile a second, impact can't be transmitted from front to rear. The back end of the thing that hits has arrived at the hit place before the shock of arrival can travel back to it. It's like a train in a collision which doesn't stop all at once. A meteor hitting the Platform will telescope on itself like the cars of a railroad train that hits another at full speed."
Sally listened enigmatically.
"So," said Joe, "the punching effect isn't there. A meteor hitting the Platform won't punch. It'll explode. Part of it will turn to vapor—metallic vapor if it's metal, and rocky vapor if it's stone. It'll blow a crater in the metal plate. It'll blow away as much weight of the skin as it weighs itself. Mass for mass. So that weight for weight, pea soup would be just as effective armor against meteors as hardened steel."
Sally said: "Dear me! You must read the newspapers!"
"The odds figure out, the odds are even that the Platform won't get an actual meteor puncture in the first twenty thousand years it's floating round the Earth."
"Twenty thousand two seventy, Joe," said Sally. She was trying to tease him, but her face showed a little of the strain. "I read the magazine articles too. In fact I sometimes show the tame article writers around, when they're cleared to see the Platform."
Joe winced a little. Then he grinned wryly.
"That cuts me down to size, eh?"
She smiled at him. But they both felt queer. They went on into the interior of the huge space ship.
"Lots of space," said Joe. "This could've been smaller."
"It'll be nine–tenths empty when it goes up," said Sally. "But you know about that, don't you?"
Joe did know. The reasons for the streamlining of rockets to be fired from the ground didn't apply to the Platform. Not with the same urgency, anyhow. Rockets had to burn their fuel fast to get up out of the dense air near the ground. They had to be streamlined to pierce the thick, resisting part of the atmosphere. The Platform didn't. It wouldn't climb by itself. It would be carried necessarily at slow speed up to the point where jet motors were most efficient, and then it would be carried higher until they ceased to be efficient. Only when it was up where air resistance was a very small fraction of ground–level drag would its own rockets fire. It wouldn't gain much by being shaped to cut thin air, and it would lose a lot. For one thing, the launching process planned for the Platform allowed it to be built complete so far as its hull was concerned. Once it got out into its orbit there would be no more worries. There wouldn't be any gamble on the practicability of assembling a great structure in a weightless "world."
The two of them—and the way they both felt, it seemed natural for Joe to be helping Sally very carefully through the corridors of the Platform—the two of them came to the engine room. This wasn't the place where the drive of the Platform was centered. It was where the service motors and the air–circulation system and the fluid pumps were powered. Off the engine room the main gyros were already installed. They waited only for the pilot gyros to control them as a steering engine controls an Earth ship's rudder. Joe looked very thoughtfully at the gyro assembly. That was familiar, from the working drawings. But he let Sally guide him on without trying to stop and look closely.
She showed him the living quarters. They centered in a great open space sixty feet long and twenty wide and high. There were bookshelves, and two balconies, and chairs. Private cabins opened from it on different levels, but there were no steps to them. Yet there were comfortable chairs with straps so that when a man was weightless he could fasten himself in them. There were ash trays, ingeniously designed to look like exactly that and nothing else. But ashes would not fall into them, but would be drawn into them by suction. There was unpatterned carpet on the floor and on the ceiling.
"It's going to feel queer," said Sally, oddly quiet, "when all this is out in space, but it will look fairly normal. I think that's important. This room will look like a big private library more than anything else. One won't be reminded every second, by everything he sees, that he's living in a strictly synthetic environment. He won't feel cramped. If all the rooms were small, a man would feel as if he were in prison. At least this way he can pretend that things are normal."
Her mind was not wholly on her words. She'd been frightened for Joe. And he was acutely aware of it, because he felt a peculiar after–effect himself.
"Normal," he said drily, "except that he doesn't weigh anything."