I clip a tether to a convenient hole on the unit (presumably put there for this exact use), and pull the lever over to the open position.

The sampler floats free of the hull.

I work my way back across the hull to the airlock with the sampler in tow. I cycle my way back in and climb out of the suit.

“All is good, question?” Rocky asks.

“Yes.”

“Good!” Rocky says. “You inspect with science gear, question?”

“Yes. Now.” I bring up the Centrifuge panel. “Prepare for gravity.”

“Yes, gravity.” He grips handholds with three of his claws. “For science gear.”

Once the centrifuge spins up, I get to work in the lab.

Rocky scurries into his tunnel in the lab ceiling and watches intently. Well, not “watches.” Listens intently, I guess.

I lay the sampler on the lab table and open one of the panels. This is the side that faced Tau Ceti. I smile at what I see.

I crane my head to look up at Rocky. “This panel was white when we started; now it’s black.”

“Not understand.”

“The sampler’s color changed to the color of Astrophage. We got a lot of Astrophage.”

“Good good!”

Over the next two hours, I scrape everything off of both halves of the sampler, putting each group in their own containers. Then I give each sample a good rinse with water and let the Astrophage settle to the bottom. I’m sure a lot of that sticky substance came with the Astrophage when I scraped it off, and I want it gone.

I perform a series of tests. First I run a few Astrophage through DNA-marker testing to see if they are identical to the Astrophage found at Earth. They are—at least, the markers I checked are identical.

Then I check overall population of each sample.

“Interesting,” I say.

Rocky perks up. “What is interesting, question?”

“Both halves had approximately the same population.”

“Not expected,” he says.

“Not expected,” I agree.

One side of the sampler pointed toward Tau Ceti, while the other pointed toward Adrian. Astrophage migrate to breed. For every frisky Astrophage that heads to Adrian with a twinkle in its eye, two should return. So, broadly speaking, there should be twice as many Astrophage going from Adrian to Tau Ceti as there are going the other direction. But that’s not what’s happening. The outgoing population is the same as the incoming population.

Rocky climbs along the tunnel that runs across the roof of the lab to get a better look. “Flaw in counting, question? How you count, question?”

“I measure total heat energy output of both samples.” It’s a surefire way to know how much Astrophage you’re dealing with. Each one insists on being 96.415 degrees Celsius. The more of them there are, the more total heat will be absorbed by the metal plate I put them on.

He taps two claws together. “That is good method. Population must be same. How, question?”

“I don’t know.” I smear some of the “returning” Astrophage (that is, the Astrophage that was on the way from Adrian to Tau Ceti) onto a slide. I take it to a microscope.

Rocky scampers along his tunnel to keep up. “That is what, question?”

“Microscope,” I say. “It helps me see very small things. I can see Astrophage with this.”

“Amaze.”

I take a look at the sample and gasp. There’s a lot more than just Astrophage in there!

The familiar black dots of Astrophage are all over the sample. But so are translucent cells, smaller bacteria-looking things, and larger amoeba-like things. There are thin things, fat things, spiral things…too many to count. Too many different kinds of things to count. It’s like looking at all the life in a drop of lake water!

“Wow!” I say. “Life! There’s a whole bunch of life in here! Not just Astrophage. A bunch of different species!”

Rocky literally bounces off the tunnel walls. “Amaze! Amaze amaze amaze!”

“Adrian isn’t just a planet,” I say. “Adrian is a planet with life, like Earth or Erid! That explains where the methane comes from. Life makes methane!”

Rocky freezes. Then he shoots bolt-upright. I’ve never seen him raise his carapace so high. “Life is also reason for population discrepancy! Life is reason!”

“What?” I say. He’s more excited than I’ve ever seen him. “How? I don’t understand.”

He taps the tunnel wall with his claw, pointing at my microscope. “Some life on Adrian EATS Astrophage! Population in balance. Natural order. This explains all things!”

“Oh my God!” I gasp. My heart just about beats out of my chest. “Astrophage has a predator!”

There’s a whole biosphere at Adrian. Not just Astrophage. There’s even an active biosphere within the Petrova line.

This is where it all started. Has to be. How else can we explain countless extremely different life-forms that all evolved to migrate in space? They all came from the same genetic root.

Astrophage was just one of many, many life-forms that evolved here. And with all life, there is variance and predation.

Adrian isn’t just some planet that Astrophage infected. It’s the Astrophage homeworld! And it’s the home of Astrophage’s predators.

“This is amazing!” I yell. “If we find a predator…”

“We take home!” Rocky says, two octaves higher than normal. “It eat Astrophage, breed, eat more Astrophage, breed, eat more more more! Stars saved!”

“Yes!” I press my knuckles against the tunnel wall. “Fist-bump!”

“What, question?”

I rap the tunnel again. “This. Do this.”

He emulates my gesture against the wall opposite my hand.

“Celebration!” I say.

“Celebration!”

The crew of the Hail Mary sat on the couch in the break room, each with their drink of choice.

Commander Yáo had a German beer, Engineer Ilyukhina had a distressingly large tumbler of vodka, and Science Specialist DuBois had a glass of 2003 Cabernet Sauvignon that he had poured ten minutes in advance to ensure it had time to breathe.

The break room itself had been a struggle to arrange. Stratt didn’t like anything that wasn’t directly related to the mission, and an aircraft carrier wasn’t exactly overflowing with extra space. Still, with more than a hundred scientists from all over the world demanding a place to relax, she had relented. A small room in the corner of the hangar deck was built to house the “extravagance.”