Chapter no 25

Project Hail Mary

‌We did it!‌

We actually did it!

I have Earth’s salvation in a little tank on the ﬂoor. “Happy!” Rocky says. “Happy happy happy!”

I’m so giddy I might throw up. “Yes! But we’re not done yet.”

I strap myself into my bunk. A pillow tries to ﬂoat away, but I snag it in time and wedge it under my head. I’m all wired up, but if I don’t go to sleep soon, Rocky will start hassling me. Sheesh—you almost ruin a mission one time and all of a sudden you have an alien-enforced bedtime.

“Taumoeba-35!” Rocky says. “Took many many generations but ﬁnally success!”

It’s a weird feeling, scientiﬁc breakthroughs. There’s no Eureka moment. Just a slow, steady progression toward a goal. But man, when you get to that goal it feels good.

We linked the ships back up together weeks ago. Rocky was pretty stoked to have access to his much larger ship again. First thing he did was set up a tunnel directly from his portion of the Hail Mary to the Blip-A. It meant another hole in my hull, but at this point I trust Rocky to do any engineering task. Heck, if he wanted to do open-heart surgery on me, I’d probably let him. The guy is amazing at this stuﬀ.

With the ships linked, I can’t have the Hail Mary’s centrifuge going, which means we’re back to zero g. But now that we’re just breeding Taumoeba in tanks, I can live without my gravity-dependent lab equipment for now.

Over the weeks, we watched generation after generation of Taumoeba become more and more nitrogen-resistant. And now, today, we ﬁnally have

Taumoeba-35: a strain of Taumoeba that can survive 3.5 percent nitrogen in a

0.02 atmosphere overall air pressure—the same situation found on Venus. “You. Be happy now,” Rocky says from his workbench.

“I am, I am,” I say. “But we need to get to 8 percent so it can survive on

Threeworld. Until then, we’re not done.”

“Yes yes yes. But this is moment. Important moment.” “Yeah.” I smile.

He ﬁddles with some kind of new gadget. He’s always working on one thing or another. “Now you make exact Venus atmosphere in one tank and do detailed tests on Taumoeba-35, question?”

“No,” I say. “We’ll keep going until we get to Taumoeba-80. It should work on Venus and Threeworld. I’ll test everything then.”

“Understand.”

I turn to face his side of the room. The whole “watching me sleep” thing doesn’t creep me out anymore. If anything, it’s comforting. “What are you working on?”

The device is clamped to his workbench to keep it from drifting away. He works on it from many angles with many hands holding many tools. “This is Earth electricity unit.”

“You’re making a power converter?”

“Yes. Convert from Eridian prime-sequence electric amplitude to ineﬃcient Earth direct-current system.”

“Prime sequence?”

“Would take long time to explain.”

I make a mental note to ask about it later. “Okay. What will you use that for?”

He puts down two tools and picks up three more. “If all plans work, we make good Taumoeba. I give you fuel. You go Earth and I go Erid. We say goodbye.”

“Yeah, I guess,” I mumble. I should be happier about surviving a suicide mission, returning home a hero, and saving my entire species. But saying goodbye to Rocky forever will be hard. I put it out of my mind.

“You have many portable thinking machines. I ask favor: You give one to me as gift, question?”

“A laptop? You want a laptop? Sure, I have a bunch of them.”

“Good good. And thinking machine have information, question? Science information from Earth, question?”

Ah, of course. I’m an advanced alien race with knowledge far beyond Eridian science. I think the laptops have terabyte drives. I could copy the entire contents of Wikipedia over to him.

“Yes. I can do that. But I don’t think a laptop will work in Eridian air. Too hot.”

He points to the device. “This is just one part of thinking-machine life- support system. System will give power, keep Earth temperature, Earth air inside. Many redundant backups. Make sure thinking machine not break. If break, no Eridian can ﬁx.”

“Ah, I see. How will you read the output?”

“Camera inside convert from Earth light readout to Eridian texture readout. Like camera in control room. Before we leave, you explain written language to me.”

He certainly knows enough English to look up any words he doesn’t know. “Yeah, sure. Our written language is easy. Kind of easy. There are only twenty-six letters, but many strange ways to say them. Well, I guess there are actually ﬁfty-two symbols because capital letters look diﬀerent even though they’re pronounced the same. Oh, and then there’s punctuation…”

“Our scholars will solve. You just get me started.”

“Yes. I’ll do that,” I say. “I want a gift from you too: xenonite. Solid form and liquid pre-xenonite form. Earth scientists will want that.”

“Yes, I give.”

I yawn. “I’m going to sleep soon.” “I watch.”

“Good night, Rocky.”

“Good night, Grace.”

I fall asleep easier than I have in weeks. I have Taumoeba that can save Earth.

Modifying an alien life-form. What could possibly go wrong?

—

Back when I was a kid, like most kids, I imagined what it would be like to be an astronaut. I imagined ﬂying through space in a rocket ship, meeting aliens, and just generally being awesome. What I didn’t imagine was cleaning out sewage tanks.

But that’s pretty much what I’m doing today. To be clear, it’s not my poop I’m cleaning. It’s Taumoeba poop. Thousands of kilograms of Taumoeba poop. Each of my seven remaining fuel bays has to be cleared out of all that gunk before I can put new fuel in.

So, on the one hand, I’m shoveling poop. On the other, at least I’m in an EVA suit while I do it. I’ve smelled this stuﬀ before. It’s not great.

The gunky methane and decomposing cells aren’t a problem. If that were all I had to deal with, I’d just ignore it. Twenty thousand kilograms of gunk in a two-million-kilogram tank? Barely worth paying attention to.

The problem is there’s probably surviving Taumoeba in there. The contamination ate all the available fuel several weeks ago, so they’ve mostly starved by now. At least, according to recent samples I checked. But some of the little bastards will probably still be alive. And the last thing I want to do is feed them 2 million kilograms of fresh Astrophage.

“Progress, question?” Rocky radios. “Almost done with Fuel Bay Three.”

Fully inside the tank, I scrape black gunk oﬀ the walls with a homemade spatula and ﬂing it out through a one-meter-wide hole in the side. Where’d the one-meter-wide hole come from? I made it.

The fuel tanks have no human-sized entry hatches. Why would they? Valves and piping lead in and out, but the largest of them is only a few inches wide. I don’t have anything to ﬂush the tanks with—I left my “ten thousand gallons of water” collection back home. So for each tank I have to cut a hole, clean the gunk out, and then reseal it.

I have to say, though, the cutting torch Rocky made for me works like a charm. A little Astrophage, an IR light, some lenses, and I have a freakin’

death ray in my hands. The trick is keeping the output low. But Rocky put extra safeties in. He made sure the lenses had some impurities and they aren’t made of transparent xenonite. They’re IR-permeable glass. If the light output from the Astrophage inside gets too high, the lenses will melt. Then the beam will defocus and the cutter will be useless. I’d have to sheepishly ask Rocky to make me another one, but at least I wouldn’t cut my leg oﬀ.

So far, that hasn’t happened. But I wouldn’t put it past me.

I scrape a particularly stubborn crust of gunk oﬀ the wall. It ﬂoats away and I use the scraper to bat it out the hole. “Status on breeder tanks?” I ask.

“Tank Four still have live Taumoeba. Tank Five and higher all dead.”

I shuﬄe forward in the tank. It’s narrow enough that I can hold position by putting both boots on one side of the cylinder and a hand on the opposing side. This leaves my remaining hand free to scrape sludge. “Tank Four was

5.25 percent, right?”

“Not right. Five point two zero percent.”

“Okay. So we’re up to Taumoeba-52. Doin’ good.” “How is progress, question?”

“Slow and steady,” I say.

I ﬂick a wad of gunk oﬀ into the void. I wish I could just ﬂush the tanks with nitrogen and call it a day. After all, this Taumoeba has no nitrogen resistance at all. But it wouldn’t work. The gunk is several centimeters thick. No matter how much nitrogen I pumped in, there would be some Taumoeba it doesn’t get to—shielded by a centimeter-thick wall of their brethren.

All it takes is one survivor to start an infestation when I reﬁll the tanks with Rocky’s spare Astrophage. So I have to muck the tanks out as best I can before doing the nitrogen cleanse.

“You fuel tanks are big. You have enough nitrogen, question? I can give ammonia from Blip-A life support if you need.”

“Ammonia wouldn’t work,” I say. “Taumoeba doesn’t have a problem with nitrogen compounds. Just with elemental N2. But don’t worry, I’m ﬁne. I don’t need as much nitrogen as you think. We know 3.5 percent at 0.02

atmospheres will kill natural Taumoeba. That’s a partial pressure of less than

1 Pascal. These fuel bays are only 37 cubic meters each. All I need to do is to

squirt a few grams of nitrogen gas in here and it’ll kill everything. It’s amazingly deadly to Taumoeba.”

I put my hands on my hips. An awkward pose in the EVA suit and it causes me to ﬂoat away from the wall, but it ﬁt the situation. “Okay. Done with Fuel Bay Three.”

“You want xenonite patch for hole now, question?”

I ﬂoat out of the fuel bay and into space. I pull on my tether to bring me back to the hull. “No, I’ll do all the cleaning ﬁrst, then close them up in a separate EVA.”

I use the handholds to get to Fuel Bay Four, anchor myself in place, and ﬁre up the Eridian AstroTorch.

—

Xenonite makes for some pretty darn good pressurized gas containers.

My fuel bays are all freshly cleaned and resealed. I gave them all about a hundred times as much nitrogen as it takes to kill any natural Taumoeba hanging around. And then I just let it stay there for a while. I’m taking no chances.

After a few days of sterilizing, it’s time for a test. Rocky gives me a few kilograms of Astrophage to work with. I remember when “a few kilograms of Astrophage” would have been a godsend to everyone on Stratt’s Vat. But now it’s just, “Oh hey. Here’s a few quadrillion Joules of energy. Let me know if you want more.”

I divide the Astrophage into seven roughly equal blobs, vent the nitrogen, and squirt one blob into each fuel bay. Then I wait a day.

During this time, Rocky is aboard his ship plugging away on a pumping system to transfer Astrophage from his fuel tanks to mine. I oﬀer to help, but he very politely declines. What good could I do aboard the Blip-A anyway? My EVA suit can’t handle the environment in there, so Rocky would have to build me a whole tunnel system…it’s not worth it.

I really want it to be worth it. It’s an alien freakin’ spaceship! I want to see the inside! But yeah. Got to save humanity and stuﬀ. That’s the priority.

I check the fuel bays. Any live Taumoeba will have found the Astrophage and snacked on it. So if the Astrophage is still there, the bay is sterile.

Long story short: Two of the seven bays weren’t sterile. “Hey, Rocky!” I yell from the control room.

He’s aboard the Blip-A somewhere, but I know he can hear me. He can always hear me.

After a few seconds, the radio crackles to life. “What, question?” “Two fuel bays still have Taumoeba.”

“Understand. Not good. But not bad. Other ﬁve are clean, question?”

I steady myself with a handhold in the control room. It’s easy to ﬂoat oﬀ when you’re concentrating on conversation. “Yeah, the other ﬁve seem good.”

“How Taumoeba in bad two bays survive, question?”

“I probably didn’t clean them well enough. Some gunk remained and shielded live Taumoeba from the nitrogen. That’s my guess.”

“Plan, question?”

“I’m going back into those two, scraping them down some more, and I’ll sterilize them again. I’ll leave the other ﬁve sealed for now.”

“Good plan. Do not forget to purge fuel lines.”

With all the tanks infected, it’s safe to assume the fuel lines (currently sealed oﬀ) will also be infected. “Yes. They’ll be easier than the tanks. I just need to blow high-pressure nitrogen through them. It’ll clean out the chunks and sterilize the rest. Then I’ll test them the same as the fuel bays.”

“Good good.” He says. “What is status of breeder tanks, question?” “Still making good progress. We’re up to Taumoeba-62 now.” “Someday we ﬁnd out why nitrogen was problem.”

“Yeah, but that’s for other scientists. We just need Taumoeba-80.” “Yes. Taumoeba-80. Maybe Taumoeba-86. Safety.”

When you think in base six, arbitrarily adding six to things is normal.

“Agreed,” I say.

I enter the airlock and climb into the Orlan EVA suit. I grab the AstroTorch and attach it to my tool belt. I turn on the helmet radio and say, “Beginning EVA.”

“Understand. Radio if problem. Can help with my ship hull robot if you need.”

“I shouldn’t need it, but I’ll let you know.”

I seal the door behind me and start the airlock cycle.

—

“Screw it,” I say. I press the ﬁnal conﬁrmation button to jettison Fuel Bay Five.

The pyros pop and the empty tank ﬂoats oﬀ into the nothingness of space.

No amount of scrubbing, cleaning, nitrogen-purging, or anything else could get the Taumoeba out of Fuel Bay Five. No matter what I did, they survived and chowed down on the test Astrophage I put in afterward.

At a certain point, you just have to let go.

I cross my arms and slump into my pilot’s seat. There’s no gravity to properly slump with, so I have to make a conscious eﬀort to push myself into the seat. I’m pouting, darn it, and I intend to do it right. I’m missing a total of three of my original nine fuel bays. Two from our adventure over Adrian, and another one just now. That’s about 666,000 kilograms of fuel storage I no longer have.

Do I have enough fuel to get home? Sure. Any amount of fuel that can make me escape Tau Ceti’s gravity is enough to eventually get home. I could get home with just a few kilograms of Astrophage if I didn’t mind waiting a million years.

It’s not about getting there. It’s about how long it’ll take. I do a ton of math and I get answers I don’t like.

The trip from Earth to Tau Ceti took three years and nine months. And it was done by accelerating constantly at 1.5 g’s the entire time—which is what Dr. Lamai decided was the maximum sustained g-force a human should be exposed to for almost four years. Earth experienced something like thirteen years during that time, but time dilation worked in our favor for the crew.

If I do the long trip home with just 1.33 million kilograms of fuel (which is all my remaining tanks can hold), the most eﬃcient course is a constant acceleration of 0.9 g’s. I’d be going slower, which means less time dilation,

which means I experience more time. All told, I’ll experience ﬁve and a half years on that trip.

So what? It’s only an extra year and a half. What’s the big deal? I don’t have that much food.

This was a suicide mission. They gave us food to last several months, and that’s about it. I’ve been working my way through the food stores at a reasonable rate, but then I’ll have to rely on coma slurry. It won’t taste good but it’s nutritionally balanced, at least.

But again, this was a suicide mission. They didn’t give us enough coma slurry to get home either. The only reason I have any at all is because Commander Yáo and Specialist Ilyukhina died en route.

All told, I have three months of real food left and about forty months’ worth of coma slurry. That works out to be just barely enough food to survive the trip home with full fuel and a bit to spare. But nowhere near enough to last the ﬁve and a half years of a slower trip.

Rocky’s food is useless to me. I’ve tested it over and over. It’s chock-full of heavy metals ranging from “toxic” to “highly toxic.” There are useful proteins and sugars in there that my biology would love to make use of, but there’s just no way to sort out the poison from the food.

And there’s nothing here for me to grow. All my food is freeze-dried or dehydrated. No viable seeds or plants or anything. I can eat what I have and that’s it.

Rocky clicks along his tunnel to the control-room bulb. He goes in and out of the Blip-A so often now I often don’t know what ship he’s on.

“You make angry sound. Why, question?”

“I’m missing a third of my fuel bays. The trip home will take more time than I have food.”

“How long since last sleep, question?”

“Huh? I’m talking about fuel here! Stay focused!”

“Grumpy. Angry. Stupid. How long since last sleep, question?”

I shrug. “I don’t know. I’ve been working on the breeder tanks and fuel bays…I forget when I last slept.”

“You sleep. I watch.”

I gesture violently to the console. “I have a serious problem here! I don’t have enough fuel storage to survive the trip home! It’s 600,000 kilograms of fuel. It would take 135 cubic meters of storage! I don’t have that much space!”

“I make storage tank.”

“You don’t have enough xenonite for that!”

“Don’t need xenonite. Any strong material will do. Have much metal aboard my ship. Melt, shape, make tank for you.”

I blink a couple of times. “You can do that?”

“Obvious I can do that! You are stupid right now. You sleep. I watch and also design replacement tank. Agree, question?” He starts down the tube toward the dormitory.

“Huh…”

“Agree, question?!” he says, louder. “Yeah…” I mumble. “Yeah, okay…”

—

I’ve done a lot of EVAs now. But none were as tiring as this one has turned out to be.

I’ve been out here for six hours. The Orlan is a tough old suit and it can handle it. The same can’t be said about me.

“Installing ﬁnal fuel bay now,” I wheeze. Almost there. Stay on target.

Rocky’s ad-hoc fuel bays are perfect, of course. All I had to do was detach one of my existing bays and give it to him for analysis. Well, I gave it to his hull robot. However he uses that robot to measure stuﬀ, it does a good job. Every valve connection is in the right place and the right size. Every screw threading is perfectly spaced.

All told, he made three perfect copies of the fuel bay I gave him. The only diﬀerence is the material. My original bays were made of aluminum. Someone on Stratt’s team had suggested a carbon-ﬁber hull but she shot that down. Well-tested technology only. Humanity had sixty-odd years of testing aluminum-hulled spacecraft.

The new bays are made of…an alloy. What alloy? Dunno. Rocky doesn’t even know. It’s a mishmash of metals from non-critical systems aboard the Blip-A. Mostly iron, he says. But there’s at least twenty diﬀerent elements all melted together. It’s basically “metal stew.”

But that’s okay. The fuel bays don’t need to hold pressure. They only have to keep the Astrophage aboard the ship—nothing else. They do need to be strong enough to not break apart from the weight of the fuel inside when the ship accelerates. But that’s not hard. They could literally be made out of wood and be just as eﬀective.

“You are slow,” he says.

“You are mean.” I ratchet the large cylinder into place with straps. “Apologies. I am excited. Breeder Tanks Nine and Ten!”

“Yeah!” I say. “Fingers crossed!”

We’re up to Taumoeba-78 as of the most recent generation. That strain is breeding away in the tanks while I work on these fuel bays. The spacing is

0.25 percent, which means for the ﬁrst time ever, some breeder tanks actually have 8 percent or more nitrogen inside.

As for installing the tanks…sheesh. I’ve learned that the ﬁrst bolt is the hardest. The fuel bay has a lot of inertia and it’s hard to keep aligned with the hole. Also, the original mounting system for the bay is gone. The pyros saw to that. They never ﬁgured I’d be adding in new bays after jettisoning old ones. The pyros don’t just open a clamp. They shear the bolts clean oﬀ. And they don’t care about the damage to the mounting points.

I spend a lot of time un-suiciding this suicide mission.

While the threaded mounting holes are in reasonable shape, every one of them has a sheared-oﬀ bolt to deal with. With no bolt head, they’re a real pain in the patoot to unscrew. I’ve found that the best approach is to bring sacriﬁcial steel rods and the AstroTorch. Melt the bolt a little, melt the rod a little, and weld them together. The result is ugly but it gives me a lever arm with enough torque to remove the bolt. Usually.

When I can’t remove the bolt, I just start melting stuﬀ. Can’t be stuck if it’s liquid.

Three hours later, I ﬁnally have all the new fuel bays installed…sort of.

I cycle the airlock, climb out of the Orlan, and enter the control room.

Rocky is in his bulb waiting for me. “It went well, question?”

I wiggle my hand back and forth—a gesture interestingly common to both

humans and Eridians and with the same meaning. “Maybe. I’m not sure. A bunch of the bolt holes were unusable. So the bays aren’t connected as well as they should be.”

“Danger, question? Your ship accelerate at 15 meters per second per second.

Will tanks hold, question?”

“I’m not sure. Earth engineers often double requirements for safety. I hope they did this time. But I will test to be sure.”

“Good good. Enough talk. Check breeder tanks, please.” “Yeah, yeah. Let me get some water ﬁrst.”

He bounces and skitters down his tube to the lab. “Why humans need water so much, question? Ineﬃcient life-forms!”

I chug a full liter bag of water I’d left in the control room before the EVA. It’s thirsty work. I wipe my mouth and let the bag ﬂoat oﬀ. I push oﬀ the wall to ﬂoat down the tunnel to the lab.

“Eridians need water, too, you know.”

“We keep inside. Closed system. Some ineﬃciencies inside, but we get all water we need from food. Humans leak! Gross.”

I laugh as I ﬂoat into the lab where Rocky is waiting. “On Earth, we have a scary, deadly creature called a spider. You look like one of those. Just so you know.”

“Good. Proud. I am scary space monster. You are leaky space blob.” He points to the breeder tanks. “Check tanks!”

I kick oﬀ the wall and ﬂoat over to the breeders. This is the moment of truth. I should check them one at a time starting with Tank One, but to heck with that. I go straight to Tank Nine.

I shine a penlight into the tank and get a good look at the glass slide that was earlier covered in Astrophage. I check the tank readouts, then check the slide again.

I grin at Rocky. “Tank Nine’s slide is clear. We have Taumoeba-80!”

He absolutely explodes with noise! His arms ﬂail, his hands clatter against the tunnel walls. It’s just random notes in no discernable order. After a few seconds he calms down. “Yes! Good! Good good good!”

“Ha-ha, wow. Okay. Easy there.” I check Tank Ten. “Hey, Tank Ten is also clear. We have Taumoeba-82.5!”

“Good good good!”

“Good good good, indeed!” I say.

“Now you do much testing. Venus air. Threeworld air.” “Yes. Absolutely—”

He shifts back and forth from one tunnel wall to the other. “Exact same gases in each test. Same pressure. Same temperature. Same death ‘radiation’ from space. Same light from nearby star. Same same same.”

“Yes. I’ll do that. I’ll do all of that.” “Do now.”

“I need rest! I just did an eight-hour EVA!”

“Do now!”

“Ugh! No!” I ﬂoat over to his tunnel and face him through the xenonite. “First I’m going to breed up a bunch more Taumoeba-82.5. Just to make sure we have enough for testing. And I’ll make several stable colonies of it in sealed containers.”

“Yes! And some on my ship too!” “Yes. The more backups the better.”

He bounces back and forth some more. “Erid will live! Earth will live! Everyone live!” He curls the claws of one hand into a ball and presses it against the xenonite. “Fist me!”

I push my knuckles against the xenonite. “It’s ‘ﬁst-bump,’ but yeah.”

—

There has to be liquor somewhere. I can’t imagine Ilyukhina going on a suicide mission without insisting on some booze. I can’t imagine her going across the street without some booze, honestly. And after looking through every box in the storage compartment, I ﬁnally ﬁnd it—the personal kits.

The box has three zipped duﬀels. Each one is labeled with a crewman’s name. “Yáo,” “Ilyukhina,” and “DuBois.” I guess they never replaced DuBois’s personal kit, because I never got a chance to make mine.

Still a little mad about how that played out. But maybe I’ll get a chance to tell Stratt my feelings on the topic.

I pull the kits into the dormitory with me and Velcro them to the wall. Deeply personal belongings of three people who are now dead. Friends who are now dead.

I may have a somber moment later and spend some time looking at all these bags have to oﬀer. But for now, this is a time of celebration. I want booze.

I open Ilyukhina’s bag. There are all sorts of random knickknacks inside. A pendant with some Russian writing on it, a worn old teddy bear she probably had as a kid, a kilogram of heroin, some of her favorite books, and there we are! Five 1-liter bags of clear liquid labeled водка.

It’s Russian for “vodka.” How do I know that? Because I spent months on an aircraft carrier with a bunch of crazy Russian scientists. I saw that word a lot.

I zip up her bag and leave it Velcroed to the wall. I ﬂy through to the lab where Rocky waits in his tunnel.

“Found it!” I say.

“Good good!” His usual jumpsuit and tool-belt bandolier are nowhere to be seen. He has an outﬁt on I’ve never seen before.

“Well, well, well! What have we here?” I say.

He juts out his carapace with pride. It’s covered with a smooth cloth underlayment that supports symmetrical rigid shapes here and there. Almost like armor, but not as fully covering, and I don’t think they’re metal.

The top hole, where his vents are, is ringed with rough gems. Deﬁnitely jewelry of some kind. They’re faceted, similar to how Earth jewelry might be cut, but the quality is horrible. They’re blotchy and discolored. But they’re really big and I bet they sound great to sonar.

The sleeves leading oﬀ the shirt stop about halfway down his arms and are similarly ornamented at the cuﬀs. Each shoulder is connected to its neighbors

by loose braided cords. And for the ﬁrst time I’ve ever seen, he has gloves on. All ﬁve hands are covered in coarse, burlap-like material.

This outﬁt would severely limit Rocky’s ability to move freely, but hey, fashion isn’t about comfort or convenience.

“You look great!” I say.

“Thank! This is special clothing for celebration.”

I hold up a liter of vodka. “This is special liquid for celebration.” “Humans…eat to celebrate?”

“Yeah. I know Eridians eat in private. I know you think it’s gross to see.

But this is how humans celebrate.” “Is okay. Eat! We celebrate!”

I ﬂoat over to the two experiments mounted to the lab table. Inside one is

an analog of the atmosphere of Venus. Inside the other is the atmosphere of Threeworld. In both cases, I made them as precise as I could. I used the best reference data I have, which is considerable thanks to my collection of every human reference book ever and Rocky’s knowledge about his own system.

In both cases, Taumoeba have not only survived but thrived. They breed as fast as ever, and even the smallest amount of Astrophage injected into either experiment gets eaten immediately.

I hold the bag of vodka up. “To Taumoeba-82.5! Savior of two worlds!” “You will give that liquid to the Taumoeba, question?”

I unclip the fastener on the straw. “No, it’s just a thing humans say. I am

honoring Taumoeba-82.5.” I take a sip. It’s like ﬁre in my mouth. Ilyukhina apparently liked her vodka strong and rough.

“Yes. Much honoring!” he says. “Human and Eridian work together, save everyone!”

“Ah!” I say. “That reminds me: I need a life-support system for Taumoeba

—something that feeds them just enough Astrophage to keep the colony alive. It has to be completely automatic, has to work on its own for several years, and it has to weigh less than a kilogram. I need four of them.”

“Why so small, question?”

“I’m going to put one on each beetle. Just in case something happens to the Hail Mary on the way home.”

“Good plan! You are smart! I can make these for you. Also, today I ﬁnish fuel-transfer device. Can give you Astrophage now. Then we both go home!”

“Yeah.” My smile fades.

“This is happy! Your face opening is in sad mode. Why, question?”

“Going to be a long trip and I’ll be all alone.” I haven’t decided if I want to risk a coma on the way home. I may have to for my own sanity. Total solitude and nothing to eat but chalky, nasty coma slurry might just be too much. For the ﬁrst part of the trip, at least, I deﬁnitely plan to stay awake.

“You will miss me, question? I will miss you. You are friend.”

“Yeah. I’m going to miss you.” I take another swig of vodka. “You’re my friend. Heck, you’re my best friend. And pretty soon we’re going to say goodbye forever.”

He tapped two gloved claws together. They made a muﬄed sound instead of the usual click that comes along with the dismissive gesture. “Not forever. We save planets. Then we have Astrophage technology. Visit each other.”

I give a wry grin. “Can we do all that within ﬁfty Earth years?” “Probably not. Why so fast, question?”

“I only have ﬁfty years or so left to live. Humans don’t”—I hiccup—“don’t

live long, remember?”

“Oh.” He’s quiet for a moment. “So we enjoy remaining time together, then go save planets. Then we are heroes!”

“Yeah!” I straighten up. I’m a little dizzy now. I’ve never been much of a drinker, and I’m hitting this vodka harder than I should. “We’re the moss imporn’t people in the gal’xy! We’re awesome!”

He grabs a nearby wrench and raises it in one of his hands. “To us!” I raise the vodka. “To ush!”

—

“Well. This is it,” I say from my side of the connector.

“Yes,” says Rocky on his side. His voice is low, despite his attempts to keep it high.

The Hail Mary is all fueled up: 2.2 million kilograms of Astrophage. A full 200,000 kilograms more than she left Earth with. Rocky’s replacement tanks were, of course, more eﬃcient and had more volume than my originals.

I rub the back of my neck. “I assume our people will meet up again. I know humans will want to learn all about Erid.”

“Yes,” he says. “Thank you for laptop. Centuries of human technology all for our scientists to learn about. You have given greatest gift in history of my people.”

“You tested it in that life-support system you built for it, right?”

“Yes. That is stupid question.” He grips a handle on his side to keep in place.

Rocky had removed his direct connecting tunnel and resealed the Hail Mary’s hull. He put the airlock-to-airlock connector in place to ﬁnish packing up.

At my request, he left the xenonite walls and tunnels in the Hail Mary in place, but with a few meter-wide holes in them here and there so I can use the space. The more xenonite Earth scientists have to study the better, I ﬁgure.

The ship still smells a little like ammonia. I guess even xenonite isn’t completely immune to gas permeation. It’ll probably smell that way for a while.

“And your farms?” I say. “You double-checked them all?”

“Yes. Six redundant Taumoeba-82.5 colonies, each in separate tanks with separate life-support systems. Each with Threeworld simulated atmosphere. Your farms are functioning, question?”

“Yeah,” I say. “Well, it’s just my ten breeder tanks. But now I have them all set up with Venus’s atmosphere. Oh, and thanks for the mini-farms, by the way. I’ll install them in the beetles during my trip. I won’t have much else to do.”

He glances at a notepad. “These numbers you gave me. You are certain these are the times for me to turn around and the times for me to reach Erid, question? They are so soon. So fast.”

“Yeah, that’s time dilation for you. Weird stuﬀ. But those are the correct values. I checked them four times. You’ll reach Erid in under three Earth years.”

“But Earth is almost same distance from Tau Ceti, and you will take four years, question?”

“I’ll experience four years, yes. Three years and nine months. Because time won’t be as compressed for me as it is for you.”

“You have explained before, but again…why, question?”

“Your ship accelerates faster than mine. You’ll be moving closer to the speed of light.”

He wiggles his carapace. “So complicated.”

I point toward his ship. “All the information about relativity is in the laptop. Have your scientists take a look.”

“Yes. They will be very pleased.”

“Not when they ﬁnd out about quantum physics. Then they’ll be really annoyed.”

“Not understand.”

I laugh. “Don’t worry about it.” We’re both quiet for a while. “I guess this is it,” I say.

“It is time,” he says. “We go save homeworlds now.” “Yeah.”

“You face is leaking.”

I wipe my eyes. “Human thing. Don’t worry about it.”

“Understand.” He pushes himself along to his airlock door. He opens it and pauses there. “Goodbye, friend Grace.”

I wave meekly. “Goodbye, friend Rocky.”

He disappears into his ship and closes the airlock door behind him. I return to the Hail Mary. After a few minutes, the Blip-A’s hull robot detaches the tunnel.

We ﬂy our ships nearly parallel but with a few degrees’ diﬀerence in course. This ensures neither of us vaporizes the other with the back blast from our Astrophage engines. Once we have a few thousand kilometers of separation, we can aim in any direction we want.

Hours later, I sit in the cockpit with my spin drives oﬄine. I just want one last look. I watch the point of IR light with the Petrovascope. That’s Rocky, headed back to Erid.

“Godspeed, buddy,” I say.

I set course for Earth and ﬁre up the spin drives. I’m going home.