The Heinleiners weren't the first to work on the problem of adapting the human body to the Lunar surface. They were just the first ones to find a more or less practical answer. Most of the lung Aladdin put inside me was just an air bottle, filled with compressed oxygen. The rest was an interface device that allowed the oxygen to be released directly into my bloodstream while at the same time cleansing the carbon dioxide. A few other implants allowed some of the gas to be released through new openings in my skin, carrying off heat. None of it was new; most of it had been experimented with as early as the year 50.
But the year 50 wasn't railroad time. The system wasn't practical. You still had to wear a garment to protect you from the heat and the cold, and it had to protect you from both-extremes never seen on Earth-while at the same time keeping the vacuum from your skin, bleeding off waste heat, and a host of other requirements. Such garments were available; I'd bought two of them within the last year. They were naturally much improved from the mummy bags the first space explorers wore, but they worked on the same principles. And they worked better than the implanted lungs. If you're going to have to wear a suit, after all, what's the point of a thirty-minute supply of air in place of a lung? If you plan much of a stay on the surface you're going to have to back-pack most of your air, just like Neil Armstrong did.
And the Heinleiners did, too, for longer stays. But they'd solved the problem of what to do with the suit: just turn it off when not in use.
I supposed they'd also solved the psychological problem of the suits, which was the panic reflex when one has not breathed normally for some time, but I suspected the answer was the same one a child learns in her first swimming lesson. Do it enough, and you'll stop being afraid.
I'd done it for fifteen minutes now, and I was still frightened. My heart was racing and my palm was sweating. Or was that Gretel's?
"You'll sweat quite a bit," she said, when I asked. "It's normal. That layer of air will stay pretty hot, but not too hot to handle. Also, the sweat helps to bleed off the heat, just like it does inside."
I'd been told the suit's distance from one's body fluctuated by about a millimeter in a regular rhythm. That varied the volume considerably, sucking waste air from inside you and expelling it into vacuum in a bellows action. Water vapor went along with it, but a lot just dripped down your skin.
"I think I'd like to go back in now," I mouthed, and must have done it well enough, because I heard her say "Okay," quite clearly. That was the same circuitry the CC used to talk to me in private, back when I was still speaking to him. Aside from the respirator/air supply/field generator, and a few air ducts, not much had needed to be done to prepare me for field suit use. Some of that's because I was already wired to a fare-thee-well, as the CC had pointed out on my direct interface jaunts. Some adjustments had been made to my eardrums to keep them from hurting in fluctuating pressures, and a new heads-up display had been added so that when I closed my eyes or just blinked, I saw figures concerning body temperature and remaining air supply and so forth. There were warning alarms I'd been told would sound in various situations, and I didn't intend ever to hear any of them. Mostly, with a field suit, you just wore it. And all but a tiny portion of that, you wore inside.
The air lock I'd used to get into the secret warrens was only for inanimate objects, or people wearing inanimate objects, like the old-style suit I'd been wearing. If you had a field suit in, you simply stepped into the wall of mirror and your own suit melted into it, like a drop of mercury falling into a quicksilver pool. That was the only way to get through a null-field barrier other than turning it off. They were completely reflective on both sides. Nothing got through, not air, not bullets, not light nor heat nor radio waves nor neutrinos. Nothing.
Well, gravity got through, whatever gravity is. Don't seek the answer to that one in these pages. But magnetism didn't, and Merlin was working on the gravity part. Follow-up on that still to come.
Just before Gretel and I stepped through I saw part of the mirror wall distorted in the shape of a face. That was the only way to see through the wall, just stick your face in, and even that was tough to get used to. Gretel and her brother-what else?-Hansel did it as naturally as I'd turn my head to glance out a window. Me, I had to swallow hard a few times because every reflex I had was telling me I was going to smash my nose against that reflection of myself.
But I had no trouble this time because I wanted very badly to be on the other side of that mirror. I was running by the time I hit it. And of course there was no sensation of hitting anything-my suit simply vanished as it went through the larger field-with the result that, because some part of me had been braced for impact, had been flinching, wincing, bracing myself, it was like reaching for that non-existent top step, and I did a comical cakewalk as if the floor was coated with banana peels and came that close to a pratfall any silent film comedian would have envied.
Before you snicker, you go and try it.
Gretel claimed to be able to distinguish people's faces when covered by a null suit. I supposed that if you grew up in one it would be possible; they were still all chrome-plated masks to me, and probably would be for a long time. But I'd figured it was Hansel who poked his face through, since that's where we'd left him, watching Winston, and it was indeed him who greeted me after my maiden voyage in the new suit. Hansel was a lad of fifteen, a tall, awkward, rather shy boy with a shock of blonde hair like his sister's and a certain look in his eye I'm sure he got from his father. I thought of it as the mad scientist's gleam. As if he'd like to take you apart to see how you worked, only he was too polite to ask if he could. He'd put you back together, I hasten to add, or at least he'd intend to, though the skills might not always be up to the intent. He got that from his father, too. Where the shyness came from I had no idea. It was not inherited paternally.
"I just got a phone call from the ranch," Hansel said. "Libby says the palomino mare is about to foal."
"I got it, too," Gretel said. "Let's go."
They were off while I was still catching my breath. It had been a long time since I'd tried to keep up with children, but I didn't dare let these get out of my sight. I wasn't sure if I could find my way back to the Heinlein alone. Sounds unlikely, doesn't it? If there's one thing Lunarians are good at, it's negotiating a three-dimensional maze, or at least we'd like to think so. But the mazes of King City tend to be of two types: radiating out from a central plaza, with circular ring roads, or a north/south up/down grid. The paths of the Delambre Dump were more like a plate of spaghetti. Two days in Delambre would have any urban planner ready for a padded cell. It just growed.
The paths I was now hurrying down had been made by nothing more mysterious than obsolescent tunneling machines-one of the other things Lunarians are good at. They usually bored their way through rock, but the sort of techno-midden stratigraphy found in Delambre presented them no problems; they'd laser their way through anything. The Heinleiners had a dozen of them, all found on site, repaired, and seemingly just sort of set loose to find their own way. Not really, but anyone who had tried to find a rhyme or reason in the pathways had to figure an earthworm would have done a tidier job.
Once the wormholes were there, human crews came in and installed the flooring out of whatever plastic panels were at hand. Since those panels had been a construction staple for over a century, they weren't hard to find. The last step was to provide an ALU every hundred meters or so. An ALU was an Air Lock Unit, and consisted of this: a null-field generator with logics to run their odd locking systems at each end, a big can of air serviced weekly by autobots, and a wire running to a solar panel on top of the heap of garbage to power the whole thing. When somebody got around to it glow- and heat-wires were strung along the top of the tunnel so they wouldn't be too cold or dark, but these were viewed as luxuries, and not all parts of the tunnels had them.