“Oh,” said Greg.

She went on, “We wanted to get the maximum of protection for the EVC. We can go for a couple of days without water, but if the air goes bad — blooey,everybody in the base is dead in an hour or so, I betcha.”

“But the water plant’s up front, near the main airlock?”

“Yeah,” Anson replied. “Plumbing’s easier that way. Cost an arm and a leg to dig the EVC in so deep. We had to run big exhaust tunnels through the solid rock. Corporation decided once was enough, so when we built the water plant we put it where we had easy access.”

Greg nodded. He knew all about the exorbitant costs of digging new living and working spaces on the Moon.

“I’ve been talking to some people at the University of Texas.” Anson said, “where my husband-to-be teaches. They think our water recycling system might be useful for big cities like Houston and Dallas.”

Really?”

“Really.” Anson said, with just a hint of sarcasm at Greg’s doubting tone. I’ll be talking with some people from Houston when I get back Earthside.”

Despite himself, Greg was impressed. “You could start a whole new product line for the corporation,” he said.

“Water recycling systems for major cities,” Anson chirped happily. “We could make a mint on it, I betcha.”

Once in the adjacent tunnel she led him to its front end.

“Main airlock is through that hatch.” Anson pointed. “That’s where we garage the tractors and decontaminate surface equipment.”

“Decontaminate?”

“Vacuum off the dust, mostly,” she said, leading him away from the hatch. “Freakin’ dust gets into everything, especially moving parts. It’s a real pain in the butt.”

They walked along the front face of the tunnel until they came to another airtight hatch. Greg saw WATER FACILITY stencilled on the smoothed rock wall next to the metal hatch. Beneath the neatly stencilled letters someone had daubed in orange dayglo. You make water; we make water. And over the hatch, another graffito: Recycling is a piss-poor way of life.

“You leave them there?” Greg jabbed a finger at the graffiti.

With a half-smile Anson replied, “We scrub them off every now and then. Matter of fact, I was going to have the whole base cleaned up in your honor, but you got here too quick. These are new, though.”

Greg snorted with disdain.

“Don’t knock it too much’ Anson said. “Graffiti help people let off steam. And cleaning them up takes water that’s better used for more important things. Like living.”

He kept his silence as Anson showed him through the maze of pipes on the other side of the hatch.

“Everything in here is fully automated, so it’s not built for human comfort. Operators monitor the equipment, of course, but it runs by itself most of the time.”

“You need access for repair personnel, don’t you?” Greg asked.

“Sure. This is it, where we’re walking.”

The chamber was dimly lit, its ceiling oppressively low. Narrow walkways threaded through the convoluted piping. The place felt cold, but not dank, as a cave on Earth would. The pipes were all wrapped in insulation, Greg saw. Not a molecule of water was being wasted.

“Oxygen from the nanoprocessors comes in there,” she stretched an arm toward the shadowed recesses between the largest pipes, anodized green. “It’s in gaseous form, of course. Hydrogen comes in along those red lines. They’re mixed in those vats and the water is pumped out to the rest of the base along the blue pipes.”

“And the yellow pipes?” Greg asked.

“Used water coming in for recycling. Never eat yellow snow and never drink from a yellow pipe.”

Greg nodded in the shadowy dimness. Grinning, Anson seemed to be waiting for a reaction from him. After a few moments, though, her grin faded and she resumed her explanations.

“Hydrogen’s getting more and more expensive,” she said.

“How come? The nanomachines—”

“We have to go farther and farther out from the base to find hydrogen. We’ve picked the regolith clean of the stuff nearby.”

“Really?”

“Hey, we’re talking about individual atoms trapped in the regolith. There’s just not that much hydrogen out there. One hundredth of a percent, by mass, tops.”

“Still, the cost should be negligible.”

“Nanomachines ain’t cheap,” she said. “We have to produce them here and they won’t let us build the kind mat can reproduce themselves. Scared of runaways that could eat up the Moon, or some equally buttheaded scenario.”

Greg kept silent. He knew all about the reasons for the strict safety regulations.

“So the bugs are designed to operate only during the lunar night. After a few day-night cycles they break themselves down and we have to produce another batch.”

“But they can’t cost very much. A few kilograms can produce their weight in hydrogen thousands of times over, from the reports I’ve seen.”

Anson waved one hand in the air. “Yeah, but at our current rate of consumption we’ll have cleaned out the whole crater floor of hydrogen in another five years. Then it’ll be cheaper to import hydrogen from Earthside.”

“But you recycle…”

“Sure, but recycling isn’t a hundred percent efficient, of course.”

Greg thought a moment. “That’s why Brennart’s mission to the south pole is important.”

“Water’s valuable, even if it’s a thousand klicks away. We can use nanomachines to build a pipeline easily enough.”

“I wonder how much water they’ve found down there,” Greg said.

“Enough to last us until we’re ready to scoop volatiles from passing comets, I hope.”

Greg knew about the comet-scooping idea; it had been relegated to the realm of far-future projects that had neither funding nor anything else except the sketchiest of conceptual drawings.

“Won’t that be expensive?” It was the usual question, expected.

Anson laughed. “Sure it will, but then we won’t have to depend on Earthside for water. Our goal is to be self-sufficient.”

That surprised Greg. “Self-sufficient? When was that made a goal?”

“It’s our goal,” Anson said, “not the corporation’s. The goal of the Lunatics who keep coming back here no matter how many times they return Earthside.”

“Self-sufficient,” Greg repeated. It was a distant dream, he knew. These people are kidding themselves.

“Self-sufficient,” Anson repeated firmly.

“Then why aren’t you drilling for ammonia?” Greg asked.

The sudden shift of subject caught Anson by surprise. “Huh? Ammonia?”

“Nitrogen is your biggest import from Earth. The reason this base is sited at Alphonsus is that there have been seepages of ammonia and methane from below the crater floor. If you want to be self-sufficient you should be drilling for the ammonia.”

“That’s in our long-range plan,” Anson said defensively.

“Maybe we should move it up,” said Greg. “The methane could provide carbon. And hydrogen, too.”

“Not a helluva lot, according to our geological probes.”

“Shouldn’t you say selenological, rather than geological?”

She planted her fists on her hips. “I hope you’re joking.”

Greg let a ghost of a smile cross his lips. “Certainly.”

“Good. Come on, it’s almost time for dinner and we’ve got a lot of cost comparisons to do.”

The Cave was less than half full when they came in and got into line for the meal dispensers. Greg noticed that Anson studied her choices carefully before selecting soyburgers, salad and fruit drink. He punched the same buttons she did, and they carried their trays to a small table off in a corner by a pair of potted ficus trees.

They chewed through numbers with their meal, Anson pulling a palm-sized computer from her thigh pocket to call up data from the base’s main files. Greg quickly saw that while her immediate priorities were to keep costs as low as possible, her long-term goal was to make Moonbase independent of life-support imports from Earth.