“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.