The Lichen Farmer of Luna

• Chapter 1 Dust and Spores
• Chapter 2 The Green of Shackleton
• Chapter 3 Pressure Check
• Chapter 4 Shadows in the Ice
• Chapter 5 The Harvest Shift
• Chapter 6 Signs of the Fade
• Chapter 7 The Oxygen Drop
• Chapter 8 The Warden's Decree
• Chapter 9 Quarantine Sector 4
• Chapter 10 The Microbe Logs
• Chapter 11 Whispers in the Regolith
• Chapter 12 The Forbidden Strain
• Chapter 13 Breaking Protocol
• Chapter 14 Into the Shadow Tunnels
• Chapter 15 The Secret Bio-Lab
• Chapter 16 Cultivating the Renegade
• Chapter 17 Alarms Over Luna
• Chapter 18 The Spreading Gray
• Chapter 19 A Desperate Mutation
• Chapter 20 The Lunar Surface Run
• Chapter 21 Inoculating the Dome
• Chapter 22 The Final Countdown
• Chapter 23 A Breath of Fresh Air
• Chapter 24 The Council's Judgment
• Chapter 25 A New Symbiosis
• Chapter 26 The Tomorrow Crop

The fine, gray powder of Shackleton Crater had a way of creeping through even the tightest seals. No matter how meticulously Milo brushed his boots before entering the airlock, a stubborn film of regolith always managed to hitch a ride inside, clinging to his synthetic coveralls like static electricity. At twelve years old, Milo had spent more than half his life on Luna, and he knew the first rule of survival off Earth: respect the dust. It dulls drill bits, jammed air valves, and scratched suit visors until the pitch-black sky turned into a blurry smudge.

Inside Bio-Dome 3, however, the dry gray yielded to an entirely different landscape. Here, the air smelled rich and damp, saturated with moisture and the sharp, earthy scent of Cladonia lunaris—the heavy-duty, genetically modified lichen that kept the fifty thousand residents of the Shackleton Lunar Colony breathing.

Milo unlatched his outer helmet and tucked it under his arm, letting out a long breath as the atmospheric regulators whistled overhead. The artificial lighting was currently set to the low, amber glow of a simulated terrestrial dawn. Row upon row of terraced vertical racks stretched toward the curved ceiling of the dome, clad in dense mats of vibrant, bluish-green foliage. To anyone fresh off a shuttle from Earth, it might have looked like a massive, overgrown cellar mold. To Milo, it was the most beautiful garden in the Solar System.

"Morning, sleepyhead," a voice rasped from the upper catwalk.

Milo looked up to see his grandfather, Marcus, leaning over the handrail with a light-meter tucked into his top pocket. Marcus had been one of the original botanists assigned to the Shackleton terraforming initiative thirty years ago. His skin was lined like dry leather, his gray hair cropped close to avoid getting caught in the dome’s circulating fans.

"I wasn't sleeping," Milo said, stepping onto the metal mesh floor of the main corridor. "The seal on locker four was sticking again. I had to grease the gasket before I could pull my boots."

Marcus chuckled, his boots clanking soft against the steel grating as he descended the spiral staircase. "Fair enough. A stuck suit seal is a bad excuse for being late, but a blown seal is no excuse at all. Grab your moisture probe. We’ve got forty racks of the Grade-A broad-leaf to index before the sunlight concentrators track over the crater rim."

Milo nodded and reached for his tool belt hanging by the workstation. He clipped the hand-held moisture meter to his waist, next to the digital recorder and his pocket magnifier.

The lichen did not grow in soil. In the vacuum outside, the regolith was entirely devoid of organic nutrients, rich in silicates, iron, and titanium, but barren of life. Inside the dome, the engineered lichen grew directly on suspended mesh plates fed by an aerosolized nutrient mist. The organism’s fungal host anchored it firmly to the matrix, while its photosynthetic algal partner absorbed energy from the concentrated sunlight bounced down from massive mirrors orbiting high above the Moon’s south pole.

Together, the two parts of the lichen worked an quiet miracle: they absorbed the carbon dioxide scrubbed from the colony's residential sectors and pumped out continuous, steady streams of pure oxygen.

"Look at Sector Seven," Marcus said, pointing his pen toward a cluster of high racks near the central trunk of the dome's air duct. "The stomatal activity on the broad-leaf strain is up two percent from yesterday's shift. The new genetic patch for cold-tolerance took remarkably well."

Milo walked over to the designated rack, pulling out his hand-held scanner. He pressed the copper tips of the probe gently against the thick, rubbery body of a lichen thallus. The display flickered to life, glowing blue with vital statistics.

Cellular Moisture: 84%
Photosynthetic Yield: 98.2%
Oxygen Production: 1.42 L/m²/hr
Spore Density: Nominal

"Everything is running at peak," Milo reported, logging the data into the colony’s main agricultural grid. "If the output stays this high through the next rotation, Warden Vance might actually have to give us that extra water allocation for Sector Nine."

Marcus snorted softly, pulling a pocketknife from his belt to trim a tiny dry patch near the edge of a growth tray. "Don't count on Vance giving up a single drop of frozen water from the deep shadowed crater floors. The Warden looks at water the way a miser looks at gold. To him, every liter used in the bio-domes is a liter that isn't being refined into rocket fuel for the Earth shuttles."

"We need the water to make the air," Milo pointed out, stepping up on a low footstool to reach the second tier of the rack. "No air, no shuttles. Even Vance knows that."

"Vance knows numbers, kiddo," Marcus said gently, leaning against the structural frame of the rack. "He knows that the colony’s margin of safety is three percent. If oxygen generation drops by even a fraction, he doesn't see a biological problem—he sees a supply chain failure. That's why we keep our heads down, do our logs, and make sure these tiny green workers keep churning out gas."

Milo adjusted his magnifier and peered closely at the micro-structure of the plant. Under magnification, the lichen looked like a tiny, frozen forest of crystal branches. Tiny droplets of condensed water clung to the velvety surface, glittering under the artificial dawn lights. It was easy to forget, sitting in the quiet warm humidity of the dome, that just thirty centimeters beyond the reinforced glass and composite walls lay a absolute vacuum, where temperatures plunged lower than minus one hundred degrees Celsius in the deep shadows.

For a twelve-year-old raised in the underground tunnels of Shackleton, the dome was the closest thing to an outdoors. Earth was a blue marble that hung low on the horizon, seen only through the high observation ports in the main administrative spire. Milo had never felt real wind, nor had he ever seen open water resting in a lake. To him, nature was something constructed engineered precisely to keep thousands of human beings from suffocating under the endless lunar night.

"Hand me the spore collector," Marcus said, interrupting his thoughts. "It's time to check the reproductive baseline for the next batch."

Milo unclipped the vacuum-spool from his tool belt and handed it over. Marcus swept the nozzle smoothly over the surface of the mature lichen, catching the microscopic, light-sensitive spores in a sealed glass vial.

"See that?" Marcus held the vial up to the light. A faint greenish dust clung to the glass walls. "That's the future of this rock. Ten years ago, we were importing half our bio-filters from orbital stations. Now? We grow everything right here in the shadow of Shackleton."

Milo reached out to take the vial back, but as he did, his eye caught a small anomaly near the base of the structural frame of Rack Nine. It was a tiny speck no larger than a thumbprint, nestled deep within the lower folds of a broad-leaf cluster.

Unlike the rich, bluish-green hue of the healthy growth, this tiny patch was dull. It looked drained, faded to a chalky, neutral gray, almost the exact color of the raw regolith dust outside the airlock.

Milo leaned in closer, bringing his hand-held magnifier down to his eye. "Hey, Grandpa. Look at this spot on the tray nine foundation."

Marcus stepped over, shifting his reading glasses down his nose. "Where?"

"Right here," Milo said, pointing with the tip of his moisture probe. "It's lost its color. It looks... dry."

Marcus leaned down, his eyes narrowing as he stared through his glasses at the gray patch. He reached out with a gloved thumb and gently brushed the faded area. The gray lichen didn't spring back or feel spongy like the rest of the mat; instead, it crumbled instantly into a fine, colorless dust that floated down through the metal floor grating.

For a second, Marcus stayed completely still, his hand hovering over the empty spot on the tray. The light humor that usually softened his face evaporated instantly, replaced by a sharp, tight concentration.

"Is it just a dead spot?" Milo asked, looking up at his grandfather's rigid profile. "Maybe the nutrient spray nozzle got clogged?"

Marcus didn't answer immediately. He took the hand-held scanner from Milo's belt, set the sensor directly against the edge of the healthy lichen surrounding the gray void, and waited for the readout.

The screen flickered. The copper tips read the biological activity of the adjacent tissue.

Cellular Moisture: 41%
Photosynthetic Yield: 12.0%
Oxygen Production: 0.05 L/m²/hr
Status: Rapid Degeneration

Marcus pressed a few buttons, overriding the automated display to run a secondary diagnostic scan. The blue light from the screen cast deep shadows across his wrinkled brow.

"Is the nozzle clear?" Milo pressed, stepping around to check the misting line that ran beneath the tray.

"The nozzle is fine," Marcus said softly. His voice had lost its relaxed, morning rhythm. He reached into his coat, pulled out a sterile sample slide, and carefully scraped the remaining gray residue off the edge of the rack into a plastic sleeve. "The nutrient line is flowing at normal pressure."

"Then why did it die?"

Marcus sealed the sample slide with a firm snap and slipped it into his inner pocket. He looked around the vast, silent aisles of Bio-Dome 3, where thousands of green racks shimmered quietly under the artificial morning sun.

"I don't know yet," Marcus said, turning back to Milo. "And until we do, we don't say a word about this to the shift manager or the Warden's office. Understood?"

Milo blinked, surprised by the sudden edge in his grandfather's voice. "Not even to the shift log?"

"Not yet," Marcus emphasized, putting a heavy hand on Milo's shoulder. "We run a full spectroscopic analysis in the back lab first. Vance is looking for any excuse to tighten water rations and centralize authority over the bio-domes. If he thinks there's a problem with the crop yield, he'll lock down Sector Three before we can even find out what caused a single dry patch."

Milo looked back at the small, empty spot on Rack Nine where the green had turned to gray dust. A cold prickle of uneasy curiosity touched the back of his neck. Outside, the endless lunar vacuum waited silently beyond the glass, held at bay only by the vast green carpet breathing rhythmically in the quiet dome.

"Come on," Marcus said, gesturing toward the lab hatch at the end of the corridor. "Let's put this under the microscope."

The back lab of Bio-Dome 3 was tucked into the structural ring where the transparent fluoropolymer hull met the dense titanium foundation embedded in the crater wall. It was a tight room, crammed with racks of glass culture flasks, centrifugal separators, and the hum of a low-noise cryogenic chiller. Sunlight did not reach this room directly; instead, soft overhead LEDs cast a cool white illumination over stainless steel counters cluttered with pipette boxes, calibration solutions, and petrified samples of terrestrial moss preserved in epoxy block displays from Marcus’s early career on Earth.

Milo watched as his grandfather slid the plastic sleeve onto the optical tray of the high-resolution digital spectrometer. Marcus adjusted a focus knob, his thumbnail clicking against the metallic bezel of the lens assembly. On the wall-mounted screen above the workstation, the image snapped into sharp relief.

At thousand-fold magnification, the healthy structure of Cladonia lunaris looked like a dense web of woven cables. The fungal hyphae formed translucent, armor-like sheaths that encapsulated vibrant green clusters of single-celled algae. In a healthy specimen, the two organisms lived in seamless harmony: the fungus anchored the mass to the synthetic mesh, pulled trace minerals from aerosol mists, and shielded the delicate algal cells from the harsh ultraviolet rays bounce-reflected off the crater walls. In return, the algae converted carbon dioxide into energy-rich sugars and discharged pure oxygen into the dome's atmosphere.

The sample on the screen, however, looked completely different.

The clear structural filaments of the fungus were brittle and fractured, covered in minute, ragged fissures. Worse, the internal algal cells—the tiny metabolic factories responsible for the green hue—were shriveled and colorless, their cell walls collapsed like deflated balloons.

"Look at the cellular matrix," Marcus murmured, zooming in on the boundary where healthy tissue met the gray decay. "The fungal sheath hasn't just withered from lack of water. It’s lost its structural integrity. The cross-linked polymers we engineered to endure severe desiccation are dissolving."

Milo stepped closer to the screen, tracing a thumb along the bottom edge of the display frame. "Did a virus get into the misting lines? Or maybe a bacterial infection?"

"A bacterial rot would leave metabolic byproducts," Marcus replied, pointing to the baseline chemical readout scrolling down the side monitor. "Look at the gas chromatography scan. No methane, no organic acid spikes, no trace of standard bacterial breakdown. It’s completely inert. It’s as if the organic bonds just... unraveled."

Sample ID: BD3-9-0012 Fungal Integrity Index: 14.3% [CRITICAL] Algal Viability: 0.0% Trace Elements: Silica (high), Iron Oxide (nominal), Titanium (trace) Biological Pathogen Markers: NULL Contamination Status: UNKNOWN

Milo stared at the numbers. "If there's no pathogen, what caused it?"

Marcus took off his reading glasses and let them hang from the lanyard around his neck. He ran a hand over his face, leaving a streak of pale regolith dust across his temple. "That is the question of the day, Milo. And until I have an answer, we double-check the environmental feeds across the entire sector. Grab the broad-range atmospheric reader from the charging station. We’re going to inspect the whole dome floor."

Stepping back out into the main volume of Bio-Dome 3 felt like stepping into an entirely different world. The scale of the dome was overwhelming, even to someone who had grown up beneath its vast ceiling.

Shackleton Crater itself was a massive impact structure situated at the lunar south pole, spanning twenty-one kilometers in diameter. Because the Moon’s rotational axis had an tilt of only one and a half degrees, the deep interior of Shackleton had sat in perpetual darkness for over two billion years. The floor of the crater contained billions of tons of water ice mixed into the frozen regolith—the absolute lifeblood of human presence on the Moon.

However, while the floor was plunged into eternal shadow, the high mountain peaks along the crater's rim were bathed in almost constant sunlight. Decades earlier, the first engineers of the Shackleton Terraforming Project had built array after array of massive solar concentrator mirrors along those tall rim ridges. These mirrors tracked the distant sun, reflecting concentrated beams of light down into the shadows, where heavy glass bio-domes sat anchored to the basalt floor.

Bio-Dome 3 was one of five identical structures forming the agricultural heart of the colony. It was two hundred meters wide at its base, rising eighty meters to a reinforced central spire. The entire interior was arranged in concentric rings of vertical growing racks, designed to maximize the light cast down by the rim mirrors.

To walk through the outer ring of the dome was to experience the engineered paradise that made survival possible. The air moved in gentle, continuous currents, driven by massive low-velocity fans mounted along the structural ribs. The current was engineered to simulate a light terrestrial breeze, just enough to move stagnant air away from the dense mats of lichen without dislodging the delicate spore beds.

Milo walked beside his grandfather down the wide center aisle of Sector 3, holding the portable atmospheric reader out before him like a tracking device. The brass sensor wand hummed faintly as it sampled the local micro-climate every few seconds.

"Relative humidity is seventy-two percent," Milo reported, checking the digital display on the wand handle. "Carbon dioxide content is at four hundred and ten parts per million. Temperature is holding steady at twenty-one degrees Celsius."

"Check the floor level near the main drain grating," Marcus instructed, waving his hand toward the low end of the terraced array. "Heavy gases like to pool down in the drainage troughs if the lower fans lose power."

Milo ducked under a low hanging support arm of Rack Twelve, crouching near the gray composite flooring. He pressed the sensor wand against the perforated drain screen where runoff moisture was collected and directed back to the central recycling plant.

"CO2 drops slightly near the drain," Milo said. "Three hundred and ninety-five ppm. But that's normal for the drainage vector. Nothing out of spec."

Around them, the automated farming infrastructure operated with rhythmic efficiency. High above their heads, on thin steel guide wires running between the structural ribs, a pair of maintenance droids slid silently along their tracks. The droids looked like mechanical spiders, their articulated arms equipped with optical sensors, pruning blades, and targeted misting nozzles. Every few minutes, one of the droids would stop over a specific tray, extend its sensor array, deliver a precise five-milliliter jet of nutrient liquid to a thirsty patch of Cladonia lunaris, and then glide on.

"The droids aren't flagging anything either," Milo observed, watching a quad-legged unit hover over Rack Fifteen. "If there was a systemic problem with the mist composition, the automated system would have locked down the main supply line."

"The automated system only checks for things it's been programmed to recognize," Marcus said, stepping up to inspect the upper trays of Rack Eight. He pulled a fresh paper wipe from his pocket, wiped down the nutrient spray bar running beneath the shelf, and held the paper up to his eyes. It came back slightly wet with clear liquid. "Vance replaced the main sensor array last year with cheaper models from the low-orbit transport hub. They look for total dissolved solids, nitrogen ratios, and basic pH levels. If there's an exotic contaminant—or a structural failure in the engineered strain itself—those budget sensors will miss it entirely until half the crop goes gray."

"You really don't like Warden Vance, do you?" Milo asked, leaning against the rack frame while his wand finished a thirty-second atmospheric trace log.

Marcus stopped his inspection and looked down at his grandson with a dry smile. "I don't dislike Vance as a man, Milo. I dislike Vance's job, and I dislike what it does to a person's priorities. A colony director is judged by one metric back on Earth: efficiency. How much water did you extract? How many kilograms of oxygen did you produce per kilowatt-hour of power? How cheap can you keep the operational costs?"

Marcus gestured out toward the sprawling green terraces that filled the dome. "Vance looks at all this green and sees an industrial chemical plant. He thinks of it like a machine: input electricity and water, output oxygen and sugar. But it isn't just a machine. It's a living ecosystem. It's fragile. You push a machine too hard, a gear breaks and you replace it. You push an ecosystem too hard, it collapses, and everyone in the crater dies while waiting for a supply ship that is six months away."

Milo felt a familiar knot of tension form in his stomach. It was easy to forget the danger when you were surrounded by green leaves, humid air, and the comforting hum of irrigation pumps. But every kid raised in the colony was taught the basic mathematics of lunar survival before they were taught long division.

Fifty thousand people lived in the interconnected tunnels carved into the basalt walls of Shackleton Crater. Each adult human consumed roughly eight hundred grams of pure oxygen per day. The colony's mechanical scrubbing units—the massive cryogenic carbon dioxide traps located in the lower industrial sectors—could only handle a fraction of that load if the bio-domes went offline. The green mats of Cladonia lunaris weren't just decorative; they provided over eighty percent of the colony's daily atmospheric renewal.

"If Rack Nine had a dead spot," Milo said, his voice dropping slightly as a pair of shift workers carrying maintenance toolboxes walked past on the upper catwalk, "how long before it could spread to the rest of Sector Three?"

"We don't know if it can spread," Marcus corrected, though his tone was cautious. "It might have been an isolated genetic defect in that particular tissue sample—a bad clone that finally reached the end of its cellular lifespan. Genetically modified organisms, especially hyper-specialized ones like lunaris, sometimes suffer from cellular degradation after a certain number of cell divisions. It's called clonal decay."

"Can we patch it?" Milo asked. "If it's just clonal decay, can't we extract fresh wild-type DNA from the vault in Sector One and splice it back into the strain?"

"We could," Marcus said, walking slowly toward the central hub of the dome where the heavy environmental lines plunged through the floor into the colony’s primary utility shaft. "If we had authorization from the agricultural board. But accessing the deep genetic vault requires a Level Four clearance stamp from the Warden's office. And if we file a request for vault access, Vance will demand to know why our current crop yield isn't self-sustaining."

Marcus paused at the edge of the central railing. Below them, through a thick quartz viewing window, lay the dark, icy depths of the primary sump shaft. Deep pumps thrummed with a low, bone-rattling vibration, bringing up melted water from the permanently shadowed ice deposits thousands of meters down in the crater floor.

"Let's check the secondary trays in Sector Four," Marcus said, turning away from the sump window. "I want to know if this gray dust is an isolated incident on Rack Nine, or if we’re looking at something larger."

They spent the next two hours moving systematically through the adjacent corridors. Sector Four housed the specialized nursery arrays—smaller, tightly monitored trays where young lichen cultures were grown from microscopic spore clusters until they were tough enough to be transferred to the high-yield production racks in the main dome volume.

The nursery was quieter than the rest of the dome. The air here was slightly warmer, kept at twenty-four degrees Celsius to encourage rapid cell division, and the light was tuned to a warmer, reddish spectrum that promoted algal photosynthesis.

Milo moved his sensor wand over Tray Array 4-B. The young lichen mats here were barely two centimeters thick, growing in neat, emerald-green squares on dark porous ceramic tiles.

"Tray 4-B looks nominal," Milo called out, reading the statistics off his wand display. "Moisture index is eighty-eight percent. Spore density is high. No sign of discoloration."

"Same here on 4-C," Marcus replied from two aisles over. "The growth rates are tracking perfectly against the seasonal baseline."

Milo relaxed his shoulders slightly. The tension that had been building since they scraped the gray dust off Rack Nine began to ease. Maybe his grandfather was right. Maybe it was just an isolated genetic defect—a single dud square in a sea of millions of healthy, oxygen-churning organisms.

He walked down to the end of Row 4-B, where the primary air intake vent drew air from the colony's residential sectors through a thick series of particulate filters. The vent made a steady, deep rushing sound, like a distant waterfall.

Milo leaned against the safety rail near the intake housing and looked down at the base of the duct assembly.

A small access panel near the floor had been left unlatched, resting half an inch open on its hinges. It was a minor code violation—all maintenance panels were supposed to be screwed flush to prevent dust accumulation in the lower air channels. Milo reached down to press the hatch shut, but stopped short.

Drifting out from the narrow gap between the metal panel and the duct frame was a faint streak of pale gray powder.

It had settled in a delicate, powdery line across the black rubber seal of the frame, caught in the low draft of the intake vent.

Milo knelt on the cold floor grating. He extended his hand-held magnifier and pointed it at the latch mechanism.

The powder wasn't regolith dust from the outside surface. Regolith particles were sharp, jagged, and glass-like under magnification, the result of billions of years of micrometeorites smashing lunar rock without an atmosphere to smooth the edges.

The dust clinging to the access panel was different. It consisted of smooth, tiny, hollow spheres—the exact same collapsed, dry fungal fragments they had examined under the microscope in the back lab an hour ago.

"Grandpa," Milo called out, his voice sharp in the quiet nursery aisle. "You need to see this."

Marcus came around the corner quickly, his boots clicking hard against the steel floor. He didn't ask questions; he simply followed Milo's gaze down to the bottom of the intake vent.

Marcus squatted beside Milo, pulling his pocket flashlight out to illuminate the interior of the hatch frame. Through the narrow crack, the light revealed a thin coating of gray dust coating the inside walls of the air channel. It looked as though a small puff of the withered material had been carried directly through the ventilation system from somewhere else deep inside the colony's infrastructure.

"That vent doesn't feed from the dome," Marcus said quietly, his brow furrowing as he traced the path of the ductwork back toward the rear bulkhead. "That's an intake line coming directly from the main circulatory loop of Sector Four Residential."

"How could lichen dust get into the residential air supply?" Milo asked. "They don't grow lunaris in the living quarters. The air there is just scrubbed gas moving through the mechanical ducts."

Marcus didn't answer immediately. He unsheathed his utility tool, slipped the flat edge into the latch release of the access hatch, and turned it with a firm click.

The heavy metal panel swung open, revealing the dark interior of the four-foot-wide air channel. The air rushing through the vent smelled dry, warm, and metallic—the distinct scent of human living quarters, mixed with something else. A faint, bitter smell, like scorched paper or dried tea leaves.

Sticking his flashlight deep into the duct, Marcus illuminated the long metal tube.

The floor of the main ventilation pipe was covered in a thin, continuous trail of gray dust that stretched backward into the dark, curving out of sight toward the outer bulkheads of the dome.

"It's not just Rack Nine," Marcus whispered, the beam of his flashlight shaking slightly against the interior wall of the duct. "It’s coming from outside Sector Three entirely."

Milo looked at the trail of gray powder stretching into the darkness of the utility pipe. Beyond that pipe lay miles of dark, cold tunnels, the heavy concrete walls of the colony, and fifty thousand people who went to sleep every night trusting that the green plants of Shackleton would never stop breathing.

Marcus pulled his flashlight back and slammed the metal hatch shut, turning the latch until it locked with a heavy snap. He stood up, turning to face Milo with an expression that Milo had never seen on his grandfather's face before. It wasn't just concern or annoyance at administrative red tape. It was genuine, cold apprehension.

"We need to run a full system diagnostic on the atmospheric intake fans," Marcus said, his voice clipped and precise. "And we need to check the pressure differentials across the main seal bulkheads before the mid-day shift change."

"What about the log?" Milo asked softly. "If this is coming through the main vents, the shift manager is going to see the drop in intake air quality during the noon report."

"Then we have until noon to figure out what is coming through those pipes," Marcus replied, grabbing his tool bag from the workstation shelf. "Pack up the sensor wand, Milo. We're going down to the lower pressure stations."