by Glenn Damato
The super-snot sickness finally fades and spaceball makes a comeback. “Try to get in two games every day,” orders Blair Rizzo. “We’ve all lost muscle and cardio fitness over the past month. This will help prepare us for working under gravity.”
On 46 Taurus, Eric announces the GNC will perform a midcourse correction, another trajectory adjustment to compensate for the tiny but cumulative gravitational influences of the planets. “The thrusters will burn for just under three minutes. I don’t like this because it will use up more than half our remaining propellant.”
This time we avoid the head-spins by lying flat in our sleepers.
The oxygen generators lose one half of one percent of their output every day. The compressed reserve comes on-line intermittently to maintain enough O2 partial pressure.
I ask Eric, “What can we do to get the reserves full again?”
“They’re reserves, Cristina. If you extrapolate the decrease, every spacecraft will arrive with a fifty-percent surplus, except Endurance might be down to forty. As soon as we land we’ll be able to produce O2 directly from the atmosphere with the solid oxide units, before we even go out on the surface.”
“That’s if your assumptions hold out. We should hedge by cutting out spaceball. Uses up more oxygen, doesn’t it?”
Eric frowns. “I’ll pass that up to the captain.”
“You do what you want. There won’t be any more spaceball on Liberty.”
Schedules drift apart again. Only Shuko is around at every meal—always pleasant, too. Is he still hoping? Clearly not going to happen, so why not communicate his interest to one of the other girls? I mean, it’s two-to-one! Why should Ryder have all the fun with the other three?
Finally, a bit of joy. Ten days before landing, Senuri comes on vid. “At nine-twenty Protonilus Coordinated Time, Doctor Hannah Lacy became the first person in world history to see the disk of Mars with her unaided eyes.”
Scattered cheers and applause ring from the com. We rush to the big window. Eric says, “I’m going to adjust everyone’s attitude so the bulk of your TMI blocks the sun.”
Ryder flicks the lights off. Yes—no longer just a point of light, Mars is a teeny pink-orange dot, barely large enough to have a shape. But it’s now more than just a speck; it’s a place.
Paige whispers, “Still so far away.”
Ryder’s voice cracks with excitement. “Look close, see if you can spot the moons. There are two, and one orbits in less than eight hours.”
Darien tells us, “We’re still twelve million kilometers out, too far to see Phobos and Deimos. The disk is only two minutes of arc wide, about one sixteenth the size of a full moon from Earth. Be another few days before we can make out features.”
“Bullshit,” Ryder snarls. “I can see features right now. I see mountains and I can even see the exact spot I’m going to build a house.”
Mikki calls from her sleeper, “You are the biggest liar ever born.”
I place my hand atop his head. “Keep lying. Lie until it comes true.”
◆◆◆
The joy is short-lived. I wake to a muffled voice: Shuko in an uncharacteristic angry tone. Something must be exceptionally wrong.
Shuko’s almost snarling. “You’re wasting the cartridges. Brief exposure is harmless.”
Senuri’s on vid. She pulls the EOB from her mouth and coughs. “Easy for you to say! It’s burning the hell out of my throat.”
I stop my forward motion with Shuko’s arm. “What’s going on?”
“Air problem on Endurance.”
“Oxygen?”
“Particulate contamination. Potassium hydroxide.”
That’s the electrolyte in the oxygen generators. “Get Eric.”
Liberty’s oxygen partial pressure is what it should be, twenty-four kilopascals. But the output of all three generators is only sixteen percent, compressed reserve eighty-five percent. There’s an orange message on the warning panel: potassium hydroxide air particulate 2.6 mg/cubic meter. There’s been an upward trend for ten days.
Eric clears his throat. “I expected this. The seals are leaking. There’s something like fifty O-rings and polyethylene gaskets in each unit. The high temps and continuous operation create hot spots. This is a known issue. We’re not going to suffocate, Cristina. There’s some electrolyte precipitating out, but there’s an easy fix. Just put a HEPA filter on your O2 bleed. It’s threaded to fit.”
“So this is happening to everyone?”
“Yeah, because everyone’s O2 sets are running hot with low-flow. My projections are holding. Nobody’s under seventy percent reserve. We’ll land in nine days with forty percent or more reserve.”
“Shit, Eric! That’s twenty hours’ margin, and you’re happy?” I face Shuko. “Let’s get the filter attached and get everyone up.”
We pull the others out of their sleepers, Alison directly from Ryder’s arms. They stare at me with identical frowns.
“This is my fault,” I tell them. “I promised to come up with an alternative way to produce oxygen. I got nowhere. I need your help.”
Mikki mutters, “Imagine that.”
Ryder yawns. “Did you have any ideas at all?”
I answer, “No, but we have time, even if the O2 generators in the TMI don’t last much longer. Forty kilos of oxygen would protect us against total failure. Eric knows a lot, but he’s limited to what’s in the manuals. We need to think beyond the manuals.”
Alison asks, “Can we print a duplicate OGS and run it right here?”
“Good thinking, but the docs don’t carry the full printer spec. In theory we can try designing our own, but a weightless type OGS works with ultrasonics, and they’re complicated and difficult to design properly.”
“Each of us exhales a kilo of carbon dioxide every day,” says Shuko. “The scrubber removes it and vents it into space. Can we redirect that CO2 to a tank and strip out the oxygen?”
I think for a moment. “We have two devices that strip O2 from CO2, the two solid oxide units. They’re designed to pull oxygen right out of the Mars atmosphere because it’s almost all CO2. But they don’t work without gravity.”
Ryder grips the table edge. “Why can’t we repair the existing OGS units?”
“Eric considers that unrealistic and I agree with him. They’re inside the TMI and obstructed by other equipment. If we could reach and retrieve one unit, how would we disassemble it, replace at least fifty seals, and reassemble it so it would work—without a schematic? We need a simple idea that will work.”
Paige purses her lips. “I have something, but you’re not going to like it. There’s a four-ton tank of nitrogen tetroxide on the other side of the equipment bay. Tetroxide is seventy percent oxygen by weight. I’m not sure about the best way to decompose the oxygen out of it, or how to collect the gas without gravity. A centrifuge maybe.”
Ryder asks, “Nitrogen tet, that’s the oxidizer for the landing thrusters. Would we have enough left to land?”
“It gets worse,” says Paige. “Tet is nasty stuff, toxic and reactive. Opening up that tank and dealing with it while weightless would be a big risk. I don’t know how efficient the extraction would be. In theory, we’d only need around sixty liters, less than two percent of the total. But in practice? I just don’t know.”
I tell them, “It’s an idea, and that’s what we need, ideas. Let’s see what we can come up with by noon today. If we’re lucky, the OGS units will crap-out slowly and we’ll land with a few hours’ reserve.”
Except they don’t crap-out slowly. They crap-out rapidly, with the total failure of critical seals.
TWENTY-SEVEN
Endurance and Independence are the worst cases. Electrolyte leakage causes short circuits and sudden shutdowns. The units on Liberty aren’t much better off, and by the following afternoon, slightly less than eight full days before landing, OGS unit two goes to zero output.
ERROR CODE 004 BC
CONCENTRATOR FAILURE
DUE TO A PRESSURE ERROR
“Reserves are at seventy-nine percent,” Shuko tells us. “About thirty-eight hours, plus six hours in the BioSuit packs.”
Eric growls a general announcement. “Do not attempt to manually start a unit that went down with a zero zero four error. Once the concentrator goes, it needs to be physically replaced.”
“Then let’s print one and physically replace it,” Ryder says. “I’ll go out there and do it.”
Eric shakes his head. “You can’t disassemble the unit in-place and re-assemble the parts perfectly. Even if you could it would develop the same problems. We all need new OGS units.”
Mikki mumbles, “Thanks for clarifying the obvious, fatty.”
Is the control center rotating? I’m imagining it; the sunbeams aren’t moving. I grab the solid edge of the master panel so I can think. We discussed a handful of ideas yesterday, none of them workable. A precious day wasted.
Paige tells us, “I investigated methods decomposing oxygen from tetroxide. Doesn’t look good. We’d need to print complex equipment, and if something goes wrong the cabin would be lethally contaminated. And I’m not sure if we’d have enough left for landing.”
A chemical engineer, and she has nothing. “I didn’t like that idea anyhow. There’s got to be something else.”
Not a word from Jürgen. Is he coordinating? Tess blocks access, as usual. “Maybe he expects you to do something,” she tells me in her superior tone. “Like with the star tracker. What are you waiting for?”
Ryder refuses to abandon hope of fixing the existing units. “If they can make it, I can fix it. How do we know we can’t do it if we don’t try?”
“Get a grip,” snarls Mikki. “How could we print parts without the spec? How would you even reach the thing? Use your brain!”
“Use your own! We can print standard size O-rings. I can remove a unit whole and bring it into the cabin.”
Mikki snickers. “All the cabling, the tubing, the mounting pins, you’re going to just reach inside the TMI, disconnect all that, bring it in here?”
“I can try!”
“The airlock hatches are one hundred and two centimeters wide,” Paige tells us. “The OGS units are thirty centimeters wider, even with the solenoids removed. I checked.”
It takes less than two hours for unit three to die. Another concentrator failure.
They must know the truth. “The last unit is holding at fifteen percent. Enough to support one person. That stretches the reserve to what, forty-three hours? Then six in our suit packs. We’re a hundred and eighty-two hours from landing. Now it’s a given. We have to make oxygen.”
Mikki’s eyes are screwed shut, her arms twisted together in a death grip.
Shuko tells us, “We can reduce the partial pressure. Sleep as much as possible. That would cut consumption somewhat, but nowhere near enough.”
Is everyone else down to one or two units? Eric isn’t responding. The vid from Constitution shows an empty control deck. There’s a shadow, and Darien comes into view. Even from a distance his face sparkles with sweat.
“Darien!” I call to him. “Pull Eric out of his sleeper.”
“You know what’s going on?” He’s barely audible.
“Get Eric!”
Darien’s face fills the vid. His chin trembles. “We’re not going to make it. Not all of us. That’s what they’re saying now.”
“Who’s saying that, Darien?”
“Eric, Senuri, Norberto. They’re calculating how many people each spacecraft can support. They think three at the most.”
A sniff from behind. Mikki, now curled up into a ball. Alison asks, “What does that mean?”
“Don’t worry about it,” I tell her. “Pure bullshit.”
Shuko mumbles, “No, it’s logical. Not enough reserve for six.”
“We’re going to make oxygen. Enough for everyone.” I point to Paige. “You said you know how to pull oxygen from tet. Can we do it in two days?”
“It would be hard, Cristina. We screw up, we’re dead.”
“We can try!” Ryder yells. “I’m not ready for some kind of random-selection suicide.”
“Who said random?” Paige shoots back. “We’re going to start another generation. The number of females is all that matters. We have cryonic sperm—”
“Paige!” I bark. “Don’t mention that again. Not going to happen. Do we have the specs for the equipment? And a procedure?”
Paige wipes her hand across her eyes. “I’ll have to write the specs. We’re going to need about ten kilos of copper stock, then design a centrifuge to separate the O2 from water and nitric acid.”
What did she just say?
I grab Paige’s arm. “Centrifuge!”
“To separate the gaseous oxygen.”
“A centrifuge! Because your equipment won’t work weightless, needs an acceleration force.”
“That’s right,” she answers. “The OGS uses ultrasonic separation. A centrifuge is less compact, less efficient, but it’ll serve the purpose.”
Ryder slaps his palm against his forehead. “Son of a bitch.”
◆◆◆
This is no longer a matter of oxygen. This battle is mental. Ryder and Paige aren’t finished with the design, but I have to get it out now. If fear grabs hold, no solution can work.
“We can make more oxygen. You won’t need the OGS. We’re going to replenish our reserves and land with one hundred percent. Do you hear me? All of us. One hundred percent!”
Senuri disagrees. “We conferenced with seven engineers. Do you realize that very shortly there won’t be enough reserve for any of us to land alive? The numbers show thirteen can make it—”
“Shut it, Senuri! Has El Capitán told you to pick anyone for suicide? Then listen—”
Eric growls, “Now you listen. You’re getting ahead of yourself. You don’t understand the situation or the numbers we’re dealing with. Endurance and Independence are both below seventy percent. If they act now, two can land alive, two females. The rest of us, it’ll be three females.” His voice cracks. “We can’t wait. The numbers—”
Screams and shouts drown out his words. I get it. They’re fighting over who gets to live. My fingers tremble. What if the idea doesn’t work? Some of us must die. Today.
“This is Vijay Mehta, flight director aboard Resolute. We are standing by for your instructions, Cristina. Would you please direct our preparations and give us a time estimate to test the solution?”
The uproar subsides. I need to sound as tranquil as Vijay. “Give us one hour for the spec. Everybody! Power-up both your printers. Get the stock out. You’ll need a lot of high-density polyethylene and aluminum, steel for clips and nylon for bearings. You’ll also need to print two standard motors and a compressor. This is how it works. We’re all carrying two portable oxygen generators. They’re Chēngzhăng designs, so they need lunar-level gravity or higher. We’re going to spin both of them in a centrifuge. It won’t be that big or spin very fast. A meter wide, twenty to thirty revolutions per minute.”
Senuri asks, “If it’s spinning, how the hell are you going to get the water in and the oxygen out?”
Paige looks up from her screen. “Feed water and oxygen will spin along with the generators. Once the tank is full of compressed oxygen we can stop the spin and replenish the reserve.”
Senuri moves closer to the vid. “You have no proof this can work. You’re guessing, aren’t you? Do you understand if it doesn’t work there won’t be enough reserve for anyone?”
“So give up, Senuri. Lead the way and be the first aboard Endurance to die for the sake of oxygen conservation.”
Senuri vanishes.
Eric tells us, “It has to work on every spacecraft and it has to work soon.”
I correct him. “One spacecraft can make enough oxygen for all thirty of us, and transfer it through the airlocks in cylinders.”
Would the capacity truly be enough? If not, I told a lie. But my lie worked. The
re’s no further talk of impending death.
And not a word from Jürgen. Not one word.
The printers purr and the idea becomes real. Ryder and Paige’s spec cleverly uses the oxygen tank as the centrifuge axis. One end anchors to a seat support. Two plastic one-liter tanks for deionized water are mounted above the generator cases. The compressor and motor are close to the axis—actually there are two, for balance.
Shuko pulls the oxygen generators from their storage locker. They’re sealed white cases marked with the logo of the manufacturer, Fukai. Alison finds the documentation. The largest outside dimension is sixty-eight centimeters. The subassembly that produces the oxygen, something called a polymer membrane pack, is fifty centimeters long and only twelve wide. The cases are long and narrow so they’ll be mounted parallel to the axis.
Ryder says, “We need to figure out what to do with the hydrogen.”
I ask him, “What happens to it when the units are running as designed?”
“Vented continuously. But we can’t vent hydrogen inside the cabin. Never mind the backpressure, it’s explosive and a suffocation hazard.”
“Can’t we compress it into a separate tank, like the oxygen?”
“Way harder to compress hydrogen,” answers Paige. “Even if we print a diaphragm compressor we wouldn’t be able to cool it. And it would be huge. We can use hydride pellets to absorb hydrogen and then heat them to vent it off, but there’s not enough elemental stock to print the pellets. This is a problem.”
Mikki launches herself from her hiding spot just inside the equipment bay. She looks over the spec. Her face is red, and she’s sniffling. “Any reason we can’t we vent it from a hose off the top of the O2 tank? The connection can be the upper bearing.”
Ryder grins. “A hollow bearing! Mick, I think that can work.”
She turns away. “Make it work, because I’m not going any closer to Mars without your ugly ass with me to share the misery.”
