And it had communication with Earth of high quality. So far the actual mail was only a one-way service, but even entertainment came up, and news. Once there was a television shot of the interior of the Shed. It was carefully scrambled before transmission, but it was a heartening sight. The Shed on the TV screen appeared a place of swarming activity. Robot hulls were being made. They were even improved, fined down to ten tons of empty weight apiece, and their controls were assembly line products now. And there was the space flight simulator with men practicing in it, although for the time being only robots were taking off from Earth. And there was the Moonship.
It didn't look like the Platform, but rather like something a child might have put together out of building blocks. It was built up out of welded-together cells with strengthening members added. It was 60 feet high from the floor and twice as long, and it did not weigh nearly what it seemed to. Already it was being clad in that thick layer of heat insulation it would need to endure the two-week-long lunar night. It could take off very soon now.
The pictured preparations back on Earth meant round-the-clock drudgery for Joe and the others. They wore themselves out. But the storage space on the Platform filled up. Days and weeks went by. Then there came a time when literally nothing else could be stored, so Joe and his crew made ready to go back to Earth.
They ate hugely and packed a very small cargo in their ship. They picked up one bag of mail and four bags of scientific records and photographs which had only been transmitted by facsimile TV before. They got into the space tug. It floated free.
"You will fire in ten seconds," said a crisp voice in Joe's headphones. "Ten ... nine ... eight ... seven ... six ... five ... four ... three ... two ... one ... fire!"
Joe crooked his index finger. There was an explosive jolt. Rockets flamed terribly in emptiness. The space tug rushed toward the west. The Platform seemed to dwindle with startling suddenness. It seemed to rush away and become lost in the myriads of stars. The space tug accelerated at four gravities in the direction opposed to its orbital motion.
As the acceleration built up, it dropped toward Earth and home like a tumbled stone.
10
There was bright sunshine at the Shed, not a single cloud in all the sky. The radar bowls atop the roof—they seemed almost invisibly small compared with its vastness—wavered and shifted and quivered. Completely invisible beams of microwaves lanced upward. Atop the Shed, in the communication room, there was the busy quiet of absolute intentness. Signals came down and were translated into visible records which fed instantly into computers. Then the computers clicked and hummed and performed incomprehensible integrations, and out of their slot-mouths poured billowing ribbons of printed tape. Men read those tapes and talked crisply into microphones, and their words went swiftly aloft again.