The Incident in Sixteen: Part Two of Three

Matthew A DeBarth
10 min readSep 19, 2022


By Matthew A DeBarth

First Rib Hall, Ahead of Fore Habitation Unit 01

Third Watch, 03:06 Hours

The High Commander, the Head of Security, and their four member security detail emerged from the airlock on the foreword end of their Hab Unit and turned anti-spinward toward Fore Ag Deck One.

They marched briskly uphill toward the elevator spoke in front of it, in the middle of the otherwise open rib hall. There was a pair of security officers behind them guarding the Hab Unit and another pair in front of them guarding the elevator. All of them crisply saluted as they swept past.

The elevator was waiting on them, and shot upwards and inwards as soon as they boarded and strapped in.

Gravity dwindled as they rose closer to the big central axis of the ship, until there was just a tiny hint of it. They weren’t quite at the centre of rotation here, so there was still a faint sensation of ‘down’.

The elevator dinged and everyone unstrapped. The door opened and they all pushed off hard and floated gracefully into the central axis in a unified arcing bound.

There were two more pairs of security officers here, one pair guarding the top of the elevator and one pair holding the command train for them.

Dwarfed by the tracks of the much larger pair of trains for going aft to the other Fore ribs and the Aft section beyond, the tiny train for moving further forward to the secure areas at the bow seemed almost a toy.

The two VIPs and their security detailed drifted through the open doors and strapped in once more. The little train moved quickly, and created a powerful ‘down’ towards the stern of the Arvad, a kilometre behind and below them.

They were carried ‘up’ to the bridge, past more than a hundred meters of nil-gee secure spaces, like a fifty story tower rising ahead of the bulk of the rest of the ship.

The whole ride, the High Commander’s Monocle was filled with a stream of chaotic emergency notifications, scrolling past her left eye faster than the bulkheads outside the train moving past her right.

49 Minutes Earlier And 0.92km Further Aft

The pressure surrounding Veronica didn’t change much, but the composition of the atmosphere certainly did. The external atmosphere telltales on her arm showed carbon dioxide shooting up and oxygen plummeting: air for plants, not animals.

As an atmospheric engineer, Veronica knew that this was a little deceptive; the ‘outrageously high’ concentration of carbon dioxide in here was only 0.11 percent of the atmosphere – a richer concentration that plants absolutely loved – but which was still about five to ten times too low to actually be dangerous to humans. It was elevated enough to be irritating and maybe cause drowsiness, but the carbon dioxide wasn’t what would kill you on an Ag Deck.

No, it was the oxygen.

Humans needed a steady, nearly uninterrupted supply of highly concentrated oxygen. It had to always be one-fifth of the atmosphere; as soon as it dropped to 19.5 percent it was officially too low. Any lower than that very quickly became dangerous.

Her mask took the plant air outside, added back in any missing oxygen from her hip tank, and filled her mask – and by extension, her lungs – with it. The hiss of the valve quickly grew louder as the mask started adding more and more.

Veronica’s forearm panel was too basic to tell her what the level of O2 in here was, other than just ‘low’, but the wall panel could. Veronica watched as it went from ‘safe’ to ‘dead within minutes’ while the airlock cycled.

She whistled in surprise. The noise was very loud inside her mask.

The airlock cycle completed and Veronica stepped inside the Ag Deck itself, like a space alien venturing into a world for plants. Some of the Ag Decks had oxygenated animal air, so that the Arvad’s livestock could breathe there, or humans could visit for recreation. Not AAD16, however. This was a working farm; a food factory. It had plant air, and the oxygen was separated out and pumped elsewhere in the ship for humans to breathe, and the waste CO2 from the inhabited areas of the ship was piped back here for the plants to process.

Beautiful balance. Infinite plant air and animal air. An incredibly ancient partnership.

Veronica was here to disrupt that. Sixteen needed to be harvested ahead of the shipbreakers’ arrival here, which meant lots of hands-on work. But thanks to having most of their supply of supplemental oxygen masks being expropriated by teams frantically prototyping spacesuits, they didn’t have enough masks left to do a simultaneous harvest on four Ag Decks at once.

No, it was easier to just switch the atmosphere to animal air and send a whole team in without masks at the start of first shift, which would be in a few hours.

Veronica was scheduled to join that team at the start of second shift, actually. After getting a meal and some sleep, at least.

These long days bleeding over into late nights were starting to wear her down, though. The schedule for shipbreaking was just brutal.

With a wry smile, she thought about just sleeping here in the Ag Deck, rather than going back to her quarters. There would be a breathable atmosphere in here before she left, after all. It would be like camping.

She smiled to herself as she logged into the atmospheric control panel on the wall by the airlock, thinking about napping on the grass until the crew started arriving in the morning. Silly, she thought to herself, it’s almost all wheat in here; there’s no grass in Sixteen.

Target oxygen level, she selected on the panel. 20.946 percent, she typed from memory. A familiar number: the partial pressure percentage of oxygen in an Earth-standard atmosphere.

She wondered idly what the atmospheric makeup of old Earth was now, around a century since the Arvad had lost contact with it. Probably not twenty-nine-four-six anymore, she mused.

Are you sure?, the panel asked her.

Yeah, I’m sure. She pressed ‘Confirm’ automatically.

Master Caution: Requested Oxygen Partial Pressure Exceeds Design Spec, the panel informed her.

Yeah, I know; it’s a plant air deck. Of course Earth-standard is out of spec, she thought impatiently.

She invoked a manual override.

ARE YOU SURE? Type “YES” to Confirm, the panel demanded.

Oh, come on, she thought, I’m too tired for this nonsense.

She pulled her Muse out and docked it to the panel to use the onscreen keyboard. ‘Y-E-S’, she typed on her Muse.

Manual Override. Adding Additional Oxygen, the panel relented.

Monitor Situation Closely, it warned her.

“That’s literally the only thing standing between me and my bed, you stupid machine,” she said out loud. She glanced up at the target value and nodded. “Yeah, Earth-standard. Why are you being so cranky?”

Of course, she knew the answer. Since shipbreaking had started, she had been telling all kinds of ship systems to do crazy, out-of-spec things for eight to twelve hours a day, and every one of them had been pushing back at every step…as they had been designed to do.

The Arvad’s builders had been a lot more cautious than their distant descendants had been forced to become.

The shipbreakers simply didn’t have the luxury of being cautious.

She’d recently watched over a team of plumbers that had spent about five minutes trying to drain the irrigation system in here without triggering a continuous alarm from the connected sprinkler system.

But no system that she’d worked with personally had fought her as hard as this atmospheric control panel had, she thought. Is Earth-standard oxygen levels really that big of an ask?

She started working her way deeper into the Ag Deck, keeping busy while huge amounts of oxygen was pumped into the long rectangular space, and some nitrogen was removed to keep the pressure within spec. Her mask could handle the overpressure of just adding oxygen without removing a corresponding amount of nitrogen, but the atmospheric system here maintained the Ag Deck’s overall pressure by automatically adding and removing nitrogen as the oxygen partial pressure moved.

There would be a lot to do tomorrow, and she went into a kind of autopilot as she moved aft, checking plant beds and moisture levels and growth states. She could feel the exhaustion in her body, and didn’t want to sit down or stop moving. She didn’t fully trust herself not to nod off.

There was a lot of food here on this deck – plus the three others in the farthest aft set – and the goal was to have as much of it for feeding shipbreaking work crews as possible, and nothing left aboard while this deck was cut away, shuttled down to the growing colony on the asteroid below, and put back into service there.

The safest place to store food was in a Shipbreaker’s stomach. Much better than in a pressure vessel being cut away with welding torches and shoved around by space tugs. No, the Ag Decks would be shipped empty.

As she busied herself with one of the many small steps in the long process of making this deck empty, her oxygen mask chimed at her. It was reminding her to turn it off and stow it now that she had entered an area of normal ship’s air.

She hadn’t, of course, actually left the Ag Deck, but her mask didn’t know that. It was a very simple and literal machine, not used to unusual situations like pumping a whole plant air Ag Deck up to ship-standard instead.

She carefully studied the all-green telltales on her inner arm, then twisted the valve on the tank on her hip closed, turned off the forearm display, and pulled off the mask.

Instantly, she could smell wet dirt and warm plants all around her. She relished this rare treat of actually being able to enjoy the aromas of her crops. She was a hard-working Aft farmer, and did not get the chance to just hang out in the park-type Ag Decks with breathable air like the more important Fore citizens.

She closed her eyes and took several slow, deep breaths in and out through her nose, filling her lungs with all the smells normally sealed away by her mask. She hummed contentedly. She felt good. Her weariness and exhaustion melted away and she smiled broadly, feeling the intensity of the plant lights above on her lips and cheeks and closed eyelids.

She felt great. She felt awake and alive and euphoric. She felt really, really good all of a sudden.

Her smile disappeared and she opened her eyes.

What she actually felt like was hyperoxic.

She frantically brought up her left arm and stabbed at the power button on the panel there.

One row of telltales – the external only – lit up: green, green, orange.

She relaxed a bit. Good oxygen and carbon dioxide levels. Just a caution on the nitrogen level, slightly low.

Wait, what? Low nitrogen!? Why? she thought. I didn’t ask for lower nitrogen.

You couldn’t even set a lower nitrogen level normally. The system just automatically controlled it to keep the air pressure within the standard range.

She felt confused…and oddly euphoric, still.

She quickly put on her mask and opened the valve on her hip; she didn’t trust the air in here at the moment. She looked at the internal atmosphere telltales: green, green, low nitrogen again.

She moved briskly aft, since she was now closer to that airlock than the forward one she had entered by. She needed better instruments to troubleshoot with, and there was an atmospheric control panel back there, too.

As she moved down the long rows of tall golden wheat, she watched the telltales on her wrist closely. The internal atmosphere remained the same, even as she breathed out the low nitrogen air in her lungs and was fed oxygenated air from the little tank of pure oxygen at her hip.

No, that’s not it, she noticed. The fill rate is zero. And I’m panting. I’m burning a lot of oxygen, and it’s still even and none is being added by the mask.

Inattentive to her surroundings, she walked into an empty waist-high irrigation pipe at a brisk pace and doubled over in pain. The pipe echoed hollowly.

When she folded forward, the faceplate of her mask tapped against the forearm panel on her outstretched arm, with the six telltales and the little pair of arrows bracketing each one. It was all just inches from her eyes.

No that’s not right, there are only five arrows in each row, she realized. Little up and down arrow outlines on the carbon dioxide and the nitrogen telltales – with the down arrow lit on the external nitrogen – but only a down arrow below each oxygen telltale.

Oh no, she thought.

Farmers cared deeply about low or high carbon dioxide levels, because their plants needed it. Everyone cared about low oxygen, because all humans needed that. But no one really thought about the nitrogen all that much; it was just kind of there. It didn’t do anything, other than replace removed oxygen. They monitored it because it was always changing, but no one took it very seriously.

And no one worried about high oxygen levels, in spite of how dangerous they could be, because oxygen was precious and carefully rationed and could only be added to an atmosphere manually, like from the tank at her hip or from the ship’s oxygen reserve tanks.

She panicked.

How much oxygen have I just manually added to this Ag Deck’s atmosphere, exactly?

She sprinted for the aft airlock’s control panel, taking huge gasping breaths.

And even as she burned through all the oxygen in her lungs, the familiar sensation of cold, recently decanted compressed gases filling her mask never came.

She slammed into the wall beside the atmospheric control panel, arms outstretched to slow her sprint. Her fingers stabbed at the screen, digging into a menu and then a submenu.

The oxygen partial pressure in here was 29.46 percent.

Not the 20.946 percent she had meant to type, thought she had typed, was sure she had typed.

That was way, way too much oxygen.

“Oh, fu – “

The fire alarm klaxon drowned out the rest of her shout.