There were five of them standing on the factory floor, encased in white spacesuits like a team of astronauts or tourists out for a jaunt on the Moon’s surface. Before them, on the broad, spacious floor of the otherwise empty factory, stood a set of spherical fuel tanks, the smaller sphere of a fusion reaction chamber, and the unfinished channel of an MHD generator, all connected by sturdy-looking piping and surrounded by crates of various powdered metals and bins of soot: pure carbon dust. Dan, Cardenas and three of her nanotechnicians stood in a group, encased in their spacesuits, watching the results of the nanomachines ceaseless work.
It was daylight outside, Dan knew. Through the open sides of the factory he saw the brilliant sunlight glaring harshly against the barren lunar landscape. But inside the factory, with its curved roof cutting off the glow from the Sun and Earth, the components of the fusion system looked dark and dull, like the unpolished diamond that they were.
“We start on the pumps next,” Cardenas said, “as soon as the MHD channel is finished. And then the rocket nozzles.”
Dan heard an edge in her voice. She did not like being out on the surface. Despite all her years of living on the Moon—or maybe because of them—being outside bothered her.
Selene’s factories were built out on the Moon’s surface, exposed to the vacuum of space, almost completely automated or run remotely by operators safe in control centers underground. “You okay, Kris?” he asked. “I’d feel better downstairs,” she answered frankly.
“Okay, then, let’s go. I’m sorry I dragged you out here. I just wanted to see for myself how we’re doing.”
“It’s all right,” she said, but she turned and started toward the airlock hatch and the tractor that had carried them to the factory.
“I know that the vacuum out here is great for industrial processing,” she said, apologizing. “It just scares the bejesus out of me.”
“Even buttoned up nice and cozy in a spacesuit?” Dan asked, walking across the factory floor alongside her.
“Maybe it’s the suit,” she said. “Maybe I’m a closet claustrophobe.”
Contamination was something that flatlanders from Earth took for granted. Living on a planet teeming with life, from bacteria to whales, thick with pollution from human and natural sources, and deep within a turbulent atmosphere that transports spores, dust, pollen, smog, moisture and other contaminants everywhere, cleanliness for Earthsiders was a matter of degree. That was why Dan, with his immune system weakened by the radiation doses he’d been exposed to in space, wore filter plugs and sanitary masks when he was on Earth.
In the hard vacuum of the lunar surface, a thousand times better than the vacuum of low Earth orbit, not only was the environment clean of external pollution sources, the contaminants inside most materials could be removed virtually for free. Microscopic gas bubbles trapped inside metals percolated out of the metal’s crystal structure and boiled off into the void. Thus Selene’s factories were out on the lunar surface, open to the purifying vacuum of the Moon.
“We don’t need to go through the carwash again,” Dan said, touching the arm of Cardenas’s suit. “We can go straight to the tractor.”
He walked around the bulky airlock and hopped off the concrete slab that formed the factory floor, dropping in lunar slow-motion three meters to the regolith. His boots puffed up a little cloud of dust that floated lazily up halfway to his knees.
Cardenas came to the lip of the slab, hesitated, then jumped down to where Dan waited for her.
Like all the lunar factories, this one was built on a thick concrete platform to keep the factory floor above the dusty ground. With no winds, there was little danger of contaminants blowing in from the outside. A curving dome of honeycomb lunar aluminum protected the factory from the constant infall of micrometeoroids and the hard radiation from the Sun and deep space.
The most worrisome source of pollution came from the humans who occasionally entered the factories, even though they had to wear spacesuits. Before they were allowed onto the factory floor, Dan and the others had to go through the “carwash,” a special airlock equipped with electrostatic scrubbers and special powdered detergents that removed the traces of oil, perspiration and other microscopic contaminants that clung to the spacesuits’ outer surfaces.