Through the oval porthole Jack Lamar watched their approaching shadow crawl steadily closer.
The moon's low gravity had returned a few minutes ago, and it felt as if they were already on the surface. A strong wind smoothed the terrain. The exhaust from their descent rocket illuminated the ground, revealing flashes of color in the bare rock.
   The auto landing was the easy part. At the start of their flight from Equator Base, they had been forced to make a rather urgent correction to avoid a mountain. Mission Control could almost be forgiven: it had been nearly forty years since astronauts had last visited the moon's north pole, way back in 2038 . . .
   "Ten meters, prepare for cut-off," Mission Control said.
   Jack was glad they would soon be walking, not flying. The moon wasn't round enough for satellites to stay in orbit for long - too lumpy and uneven. The gravity from a medium-sized crater could induce a measurable change, raising one end of the orbit, lowering the other.
   The rocket quit, and the lander fell smoothly on its four legs.
   "Control, we are down," Janet Melville said. "Two point two degree tilt, stable on all axes. Rover ready for deployment."
   Jack and Franz Dorfer from EuroSpace exchanged high-fives. The cramped, equipment-filled cabin was lit by matrix screens. Machinery hummed softly all around.
   "Settle down," Janet commanded. "Work to do." Franz switched control stations.
   "Activating fuel cells," he said. "Thorium gel should last 6.8 weeks at medium power." It could also make a most impressive explosion, should that prove necessary.
   The three astronauts sat in the cabin of the exploration rover Shackleton, suspended from the lander framework like a robot millipede. Its twelve folded legs hung half a meter above the dry soil.
Franz pressed a button, and the rover dropped down and bounced back on springy joints.
   "A tad too gentle," Janet said.
   "I can do even better," Franz promised.
   He steered the rover out from under the lander, straightened its legs to walking height, and began the long trek between the boulders.
With each step, rocks crunched underfoot. The ride was very smooth as the legs shuffled over the jagged terrain. The legs had thousands of tiny actuators that made a musical marching sound, step dancing in unison.
   Behind them the sun cast long shadows toward the horizon. As they advanced, the forbidding mountain range ahead rose higher.
The crew settled into their routine. Officially, this was a rescue mission.

   Jack thought about the early days of lunar colonization. Around 2025, a new generation of low-cost launchers had become available. The Energia-2 rockets weren't reusable, but putting a hundred tons in low Earth orbit became cheaper than launching one old Delta rocket. The Japanese had led the way with an outpost in the Ocean of Storms. The Chinese unexpectedly established a tiny base in 2037, and began to ship colonists to start new lives on the moon. A major ice deposit was discovered near the North Pole under deep rock.
The first Deep Base was completed just before the Insanity War broke out on Earth.
   It was hard to remember a time before the war. Alliances had changed constantly, pitting most nations against each other.
Only Franz had emerged relatively unscathed as one of the few conscientious objectors. Jack had somehow survived three pointless campaigns without permanent disability. Janet still had scars from the catastrophically misguided occupation of Tibet, and needed neural implants to control her legs.
   The inexplicable madness had finally faded out five years ago.
Shackleton's mission was to renew contact with North Base. Somehow, the colonists had survived, but how much had they changed? Cut off from the Net as a viral precaution, they would be amazed by all the new technology the rover was delivering: universal vaccines, power packs, and the latest nanbots.
Still, Jack felt bad about their secret orders.

   "Here comes obstacle one," Janet said.
   On one side a dark, jagged fissure cut a path through the lunar crust. This was the Bottomless Canyon; oblique radar surveys hadn't established its depth yet. Dense fields of rocks gave a Mars-like appearance.
On the far side, they were surprised to see an immense boulder almost the size of a small asteroid. Sunk into the regolith, its base was narrower than its middle and appeared eroded with undulating striations.
   "Let's scrub the EVA," Franz said. "There's a safe path through the rock zone."
   Jack had been hoping to test the new exo-pod. Spacesuits had mostly gone out of fashion. It wasn't practical to spend many hours inside them. These days, people ventured out in rolling bubbles with expandable sections. Astronauts called them hamsterballs, but they could almost be mobile homes.
   Despite its cramped interior, the rover was very comfortable. The ceilings were low, but crouching was easy in low gravity. High-pitched fans created a chorus of airstreams. The adventurous breeze kept them alert.
   "I wonder if North Base invented any interesting gadgets," he said. "The others have."
   "Hopefully not too many," Janet said. "Pogo Base was just weird."
   Despite their minimal populations, the isolated lunar colonies had been forced to invent much original technology during the thirty years of fighting. Genetically engineered bacteria separated useful isotopes inside nuclear reactors. Microscopic nanbots could make entire moonbases from dirt.
   It was a harsh life, and most colonies had turned isolationist. That would have to change when humanity came for the lunar resources. The abundant oxygen, metals, and minerals locked in the rocks and soil would be harvested by kilometer-high mechanical spiders crawling over the surface.
   "We're approaching the Wedge," Janet noted.
   On the forward screen, the horizon crept closer. When the rover walked over the crest, the three astronauts stared down a long descending slope at least two kilometers deep. The Wedge had been formed by the collapse of a raised crater wall. Because of its polar orientation, the Wedge was illuminated, but the surrounding mountains were in deep shadow.
An angled plain extended ahead, smooth in every direction. The slope appeared to be the only thing in the universe. Their eyes insisted it was level, with gravity pulling at an angle. Dark rocks gleamed as if embedded with tiny diamonds. The Earth's crescent was wiped away by an unseen ridge as they descended, and they lost contact with mission control.
   Franz concentrated on steering. Jack asked Janet "What's it like working for the Institute of Exodiplomacy?"
   "Boring, until Witten Observatory discovered that non-periodic pulsar."
   Two years earlier, an apparently artificial radio source had been discovered in the largest galaxy in the observable universe, almost six billion lightyears from Earth. It was called BGRX, and it took weeks for the disappointing truth to emerge.
   "Very interesting that two neutron stars can exchange matter semi-chaotically," Janet said. "We really got our hopes up there."
   "We're learning a lot from that pulsar," Jack said. "The biggest particle accelerator we'll ever see."
   "I need aliens to test my skills." After several false alarms, everyone had given up hope. Humans might be the only aliens in the universe.
   "The colonists will test us plenty," he responded. "They're the closest thing to lunar life, probably." Last year, a few bacteria from Earth had been discovered living inside the carbonaceous asteroid Nubia.
   Janet stared at the almost featureless terrain. The rover dislodged small rocks ahead of the vehicle that were apparently tumbling uphill.
   "The colors from the Apollo and Orion videos mostly seem dull gray and brown, but those rocks look almost blue, and that rubble has a yellow-tan color."
   Jack responded, "We don't see things the way a newcomer would. Our eyes adapt by exaggerating small nuances. Some of the colors aren't there. The first Mars expedition reported the landscape changed from orange-red to brown-yellow."
   "The colonists would probably go nuts on Earth."
   "There are other illusions. See that mountaintop over there?"
   "That shining peak?"
   "It's only fifty meters away."
   The rover lurched to a halt. "Achtung!" Franz said. "We have company."
   A giant metal beetle had emerged from the murk at the bottom of the slope, mandibles chewing through the dirt as it edged closer.
   "It's an extractor gathering helium-3 from the dust. The angle between this slope and the Sun is ideal to capture solar alpha particles. I thought it was too smooth to be natural. The colony has advanced technology."
   Slowly, the harvester made its way up the angled plain, ignoring the rover.
   Soon they were moving through a bizarre maze of rock formations, jutting finger-like protrusions and leaning pillars.
   "This is the Stealth Garden," Jack said, reading the 3D map. "The radar orbiter couldn't get a good echo."
   "Coming up on our left," Franz said. "The last stop before Epcot."
   At first glance, the small crater looked like every other. It wasn't perfectly round, and the surface deposits were brighter than usual.
   Janet stared at the thirty-meter trough. "Looks like it formed yesterday," she said.
   "Indeed," Franz responded. "One of the newest craters, made in 1970 by a Soviet Luna stage. By extreme coincidence, the northernmost manmade impact crater happens to be on our route."
   An hour later, the rover edged over a final rise before a deep chasm. It took several minutes for the pit's full scope to become evident. After a high-angle chain impact billions of years ago, the connected craters had collapsed in steps. No sunlight ever reached the chaotic terrain at the bottom.
Franz started their descent down a natural spiral groove along a crater wall.
   "We're being watched," Janet said.
   "They've known since we landed," Jack said.
   Looking out a small window, he saw strange rocks beside the natural roadway. Were they crystals? They looked bright enough in the glare of the rover's lights. The pressure at the moon's core was high enough for diamonds to form, but those gems rarely reached the surface. The moon had been geologically dead for eons.
   Imperceptibly, the ramp became an artificial roadway carved into the side of the pit. Steep walls and dark shapes blocked the stars. Many caves could be found in this area.
   Jack thought some of the shapes might be moving.
   "We're inside a building," Franz said finally.
   "Full stop," Janet ordered.
   Looking at the rear screen, Jack saw a door lowering behind them. Total darkness, and then a soft but rising hiss. A winter wind blew the dust off the rover.
   "Outside pressure rising fast," Janet said.

   Overhead floodlights blinked on. At first, they seemed to be in a large stadium. A round workbay surrounded them, filled with vast arrays of equipment.
   In all directions people were cheering, jumping, and waving. Almost every colonists had to be assembled in the vast chamber. Their average age appeared to be only twenty-something. Random details set everyone apart: luminescent tattoos, metallic fashions, oddly colored hair. They dressed asymmetric, unlike most cultures. Their taboos, traditions, hierarchies, and even language were still completely unknown. Jack felt a moment of profound isolation.
   Then he noticed the area beyond the work bay. It was quite a contrast. Their rover was a scientific masterpiece covered with antennas, actuators, pipes and logos, all gleaming curves and lines.
North Base looked about as messy as possible. Everywhere were seemingly haphazard support frames, improvised pipes and cables, translucent membranes, crowded rooms within rooms. The design, if it had been designed, seemed almost organic.
   "Now comes the hard part," Janet said. "You have been briefed. We can't alter their culture in any way yet."
   They recognized the colony's elderly commander from their files. Bruce Ramsary approached and looked in a porthole.
In the long seconds before Janet opened the airlock, Jack considered what they had to do.
   This colony was the most unusual one of all. The thirty remaining founders all knew the truth, but well over one hundred offspring had been raised to believe a lie. They thought their colony was thousands of years old - and that they were living in the year 5837.
   The colonists believed many strange things. They lived underground (their elders claimed) because they were hiding from the Bilarians, a horrific alien species . . .
   In the years immediately before the war, ethics had evolved beyond Jack's understanding. Bruce Ramsary had claimed a heroic heritage was necessary to prevail in this harsh environment, a virtual religion to justify their hardships.
The plan had succeeded better than anyone had dreamt. North Base was a unique experiment on the nature of truth.

   The largest collapsed crater was three kilometers deep. Below was soft rock filled with ancient air pockets. The inert gasses had escaped long ago, but the rock was excellent for tunneling. The North Base network formed a maze of random corridors.
At its heart was a great covered crater, with sunlamps hanging on cables from the high ceiling, and multi-story buildings of many types of rock.
   Jack only had attention for one thing, something he had never expected to see in his lifetime. Oversized flattened raindrops slowly fell around him like surreal pearls before walls of leaves.
   The contact team stood in the rain forest that filled the cave, which provided the colony's food and oxygen. A colonist flew a small hang glider through the mist and simulated thunder, a strange soaring kite in the low gravity. He'd leaped off a platform attached to a bungee cord that hung from the green sky. The ceiling was an upside-down forest itself.
   "An incredible accomplishment for such a small group," Jack told Al Ramsary. "Possibly the greatest achievement ever."
   The oldest offspring was a thin individual in his thirties, who looked at least a decade younger. Despite popular misconceptions, the colonists were no taller than Earthers, but the visitors did seem squat and bloated by comparison.
According to local custom, Al was a role model for his generation (B1). The whole colony had assembled for a celebration around the astronauts.
   Their society was usually very formal, to add needed complexity to their lives. They had a credit-based economy with user fees for everything, even air. Jack wondered what happened if someone couldn't afford oxygen. Apparently that had never come up.
   Jack saw Janet standing near a giant tree trunk, holding an almost full glass while talking to the commander.
   "Amazing how your civilization held out for almost four thousand years, while retaining its original culture," Jack said. "Most MicroPolises experience degenerative drift within a few centuries."
   The young-looking man said: "Actually, none of us believes that story anymore. We just humor our elders by pretending to take it seriously. We built all this, you know. They claim the Bilarians destroyed all the previous caves, but we would have found evidence of that."
   Jack managed to hide his complex emotions. "Say what?"
In Al's imagination, the astronauts from Earth probably admired his cleverness. Could this be a double bluff?
He selected the proper contingency plan.
   Jack clapped Al on the back and pushed him around a tree into a clearing, a secluded outpost where colonists probably snuck away for illicit liaisons.
He balanced his purple-green ethanol cocktail on a convenient branch, and said: "Let's make a deal."
   "About what?" Al asked.
   "My career, for one thing." Jack looked around. "Let's put it this way: you may or may not be part of a very important sociological experiment. Either way, you're not supposed to even think the current year doesn't match your official calendar. Both our bosses would get very mad."
   Al smiled. "The experiment would be ruined, and they might hold you responsible."
   "That's my conundrum," Jack agreed.
   Al's smile widened as he motioned Jack back to the party. "Don't worry," he said. "We have no intention of telling. It's more interesting this way." He thought a moment as they approached the improvised jungle bar. "In fact, we have some ideas to make this experiment even more interesting . . ."
   "Tell me everything," Jack smiled in return.

   Across the clearing, Janet and Bruce had overheard every word. The experiment was proceeding nicely; Jack had done his job better than he could know. Never suspecting his falsified identity, he had reinforced Al's belief system, who would transmit it to the other members of his generation.
Nothing more effective than reverse psychology.
Hopefully the Bilarians would be pleased.

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Probably the best hard SF novel ever written: Infinite Thunder by Jack Arcalon.
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