So we settled on Eridian steel. It’s strong, it doesn’t oxidize easily, and it’s extremely durable. Earth can cut it open with a diamond saw. And hey, they’ll probably analyze it to learn how to make their own. Everyone wins!

His approach for the farms themselves was simple. Inside, there’s an active colony of Taumoeba and a Venus-like atmosphere. Also, there’s a coil of very thin steel-ish tubing full of Astrophage. The Taumoeba can only get at the outermost layer, so they have to work their way down the tube, which has a total length of about 20 meters. Some basic experimentation tells us that will last the small Taumoeba population several years. As for waste products—they’ll just stew in their own poop. The capsule will gain methane and lose carbon dioxide over time, but it doesn’t matter. Though it’s a small volume by human standards, it’s a vast, gigantic cavern to the tiny microbes inside.

The beetles have been a priority for me. I want them ready for launch at a moment’s notice. Just in case there’s a catastrophic problem with the Hail Mary. But I don’t want to send them off if there isn’t a mission-critical problem. The closer we are to Earth when they launch, the better their odds of making it there safely.

In addition to installing the mini-farms, I also have to refuel the little buggers. I’d used almost half their fuel supply when they served as ad-hoc engines for the Hail Mary. But they only need 60 kilograms of Astrophage each to be full. Barely a drop in the bucket compared to my supply of imported, Eridian-made Astrophage.

The hardest part is opening the beetle’s little fuel bay. Like everything else around here, it wasn’t intended for reuse. It’s like adding fresh butane to a Bic lighter. It’s just not meant for that. It’s completely sealed. I have to clamp it into the mill and use a 6-millimeter bit to get in…it’s a whole big thing. But I’m getting good at it.

I finished John and Paul yesterday. Today I’m working on Ringo and, time permitting, George. George will be the easiest. I don’t need to refuel him—I never used him as an engine. I just have to attach the mini-farm.

Figuring out where to put the mini-farm was another matter. Even with its small size, it’s too big to fit inside the little probe. So I epoxy it to the undercarriage. Then I spot-weld a small counterweight to the top of the beetle. The computer inside has very strong opinions about where the center of mass of the probe is. It’s easier to add a counterweight than completely reprogram a guidance system.

Which brings us to the matter of weight.

The additional weight of the farm makes the beetles weigh a kilogram more than they should. That’s okay. I remember countless meetings with Steve Hatch discussing the design. He’s a weird little guy, but he’s a heck of a rocket scientist. The beetles know their location in space by looking at the stars, and if they have less fuel than they expected to have, they taper their acceleration down as needed.

In short: They’ll get home. It’ll just take a little longer. I ran the numbers and it’s a trivial difference in Earth time. Though the beetles will experience several additional months during the trip than the original plan.

I go to the supply cabinet and pull out the BOCOA (big ol’ container of Astrophage). It’s a lightproof metal bin with wheels. There are several hundred kilograms of Astrophage in there and I’m in 1.5 g’s of gravity. That’s why I added the wheels. You’d be amazed what you can do with a machine shop and a firm desire not to drag heavy stuff around.

I hold the handle with a towel because it’s so hot. I wheel it over to the lab table, settle into the chair, and get ready for the methodical refueling process. I get the plastic syringe at the ready. With it, I can squirt 100 milliliters of Astrophage into that 6-millimeter hole per shot. That’s about 600 grams. All told, I have to do it about two hundred times per beetle.

I open the BOCOA and—

“Ugh!” I wince and draw away from the container. It smells horrible.

“Uh…” I say. “Why does it smell like that?”

Then it hits me. I know that smell. It’s the smell of dead, rotting Astrophage.

The Taumoeba are loose again.

I leap from the stool, but I don’t have a plan.

“Okay, don’t panic,” I tell myself. “Think clearly. Then act.”

The BOCOA is still hot. That means there’s a lot of living Astrophage still in there. I caught it early. That’s good. Not because of the BOCOA—it’s toast. I’ll never be able to sort out the Taumoeba from the Astrophage in there. But it means that however the heck the Taumoeba got in there, this is very recent and hopefully hasn’t reached the ship’s fuel.

Yes. That’s priority number one. Don’t let Taumoeba into the fuel bays. Last time they got in was because of various microscopic leaks in the system. But it had to have gotten there from the crew compartments where I had brought it aboard. There isn’t much overlap between the fuel system and the crew compartment. There’s just one place that’s the likely culprit for transfer.

Life support.

If the ship is too cold, it runs air across coils filled with Astrophage to warm it up. A breach in one of those coils would do it. Lucky for me I’ve had a big pile of 96°C Astrophage in the lab keeping the crew compartment so warm the ship has to use the air-conditioning system.

Okay, now I have a plan.

I scamper up the ladder to the control room. I bring up the Life Support panel and look at the logs. As I suspected, the heater hasn’t been turned on in over a month. I deactivate the heater entirely. It shows as disabled, but I don’t trust it.

I go to the primary breaker box. It’s under the pilot’s seat. I find the breaker for the heating system and flick it off.

“Okay,” I say.

I get back in the seat and check the Fuel panel. The fuel bays all seem to be in good shape. The temperature is correct. It wouldn’t take long for Taumoeba to run wild and eat everything in a fuel bay—I know that for darn certain. If they were affected, they’d be colder than that.

I bring up the spin-drive controls and shut the engines off. The floor drops out from under me as I return to weightlessness. I probably don’t need to shut them off, but for now I don’t want the fuel doing anything. If there’s Taumoeba in a fuel line, I want it to stay there, not get pumped all over the ship.

“Okay…” I say again. “Okay…”

More thinking.

How did it get loose? I sterilized every part of this ship with nitrogen before getting a gram of Astrophage from Rocky. The only Taumoeba aboard are in the sealed mini-farms on the beetles and the sealed, xenonite breeder tanks.

No. No time for science questions. I can speculate on the cause later. Right now I have an engineering problem. I wish Rocky were here.