‌My timer beeps at me. I’d set it for a two-hour countdown. It just reached zero. I blink a couple of times. I’m floating in a fetal position in the control room. I didn’t even make it to the dormitory.‌

I am not rested at all. Every pore of my being yells at me to go back to sleep, but I told Rocky I’d be back in two hours and I wouldn’t want him to think humans are untrustworthy.

I mean…we’re pretty untrustworthy, but I don’t want him to know that.

I trudge (can you trudge in zero g? I say yes) through the airlock. Rocky is there waiting for me in the tunnel. He’s been busy in my absence. There’s all sorts of stuff in there now.

The Eridian clock is still ticking away—now mounted to one of the lattice poles. But more interesting to me is the box that’s been added to the dividing wall. It’s a 1-foot cube and it juts out into my half of the tunnel. It’s made of the same transparent xenonite that the rest of the wall is made of.

On Rocky’s side, the box has a flat panel door with an opaque xenonite border. Also, there’s a square hole with a perfectly fitted square pipe leading away.

There are some…controls?…on the pipe near the box. Buttons, maybe? A wire coming from the control box snakes along the pipe, disappearing into the hull where the pipe does.

Meanwhile, on my side of the cube is a crank, roughly the same shape as my own airlock door’s crank. And that’s attached to a square panel like the one on Rocky’s side and—

“It’s an airlock!” I said. “You made an airlock in our airlock tunnel!”

Brilliant. Simply brilliant. Rocky and I can both access it. He can control the air in that little chamber by means of the mystery pipe, which presumably leads back to some pumps or something in the Blip-A. And those buttons or whatever are the controls. Just like that, we have a way to transfer stuff back and forth.

I do jazz hands. He does them back.

Hmm. Again with the square, flat panels. Who makes a square airlock? Especially one designed to handle Eridian atmospheric pressure. Even the pipe that runs the mini-airlock is square. I know they can make round xenonite—the cylinders he sent me when we first met were round. This tunnel is round.

Maybe I’m overthinking this. Xenonite is so strong you don’t have to carefully shape it into pressure vessels. Flat panels are probably easier to make.

This is awesome. I hold up a finger—he returns the gesture. I fly down to the lab and grab a tape measure. He showed me a unit of time, so I’ll show him a unit of length. The tape measure is metric, thank God. It’s going to be confusing enough using base-6 Eridian seconds. The last thing I want to throw in there is imperial units—even if they are natural to me.

Back in the tunnel, I hold up the tape measure. I pull it out a bit, then release it to let it retract. I repeat the process a few times. He does jazz hands. I point to the “squarelock” (well, what else should I call it?) and he does jazz hands again.

I hope that means there isn’t 29 atmospheres of ammonia in there at the moment. I guess we’ll see….

I turn the crank and open my door. It swings outward toward me easily.

Nothing explodes. In fact, I don’t even smell ammonia. And it wasn’t a vacuum in there either. I wouldn’t have been able to pull the door open at all if it had been. Rocky set that up to be exactly my atmosphere. Considerate of him.

I put the tape measure in the approximate center of the box and let it float there. I close the door and turn the crank.

Rocky presses a button on the controls and I hear a muffled fwump followed by a steady hiss. A foggy gas rushes in from the pipe. Ammonia,

presumably. The tape measure bounces inside—pushed around like a leaf in the wind. Soon, the hiss dulls to a trickle.

And then I realize my mistake.

The tape measure is one of those solid, construction-site kinds that are made of metal with tool-grade rubber grip pads. Thing is, Eridians like it hot. How hot? I can’t say for sure, but I now know it’s hotter than the melting point of the rubber on the tape measure.

The blob of liquid rubber undulates on the tape measure, sticking to the tool via surface tension. Rocky opens his door and carefully grabs my faulty present by the metal. At least that’s still solid. I think it’s made of aluminum. It’s nice to know Eridian air isn’t hot enough to melt that too.

As Rocky pulls the tape measure toward him, the rubber blob separates from it and floats off in his side of the tube.

He pokes the rubber blob and it sticks to his claw. He shakes it off without much trouble. Obviously the temperature doesn’t bother him. I guess it’s no different from a human shaking water off his hand.

In my atmosphere, rubber that hot would burn. There’d be all these nasty, noxious gases coming off of it too. But there’s no oxygen on Rocky’s side of the wall. So the rubber just kind of…stays a liquid. It floats off to the tunnel wall and sticks there.

I shrug at him. Maybe he’ll know that means “I’m sorry.”

He sort of shrugs back. But he does it with all five shoulders. Looks weird and I don’t know if he caught my meaning.

He pulls the tape out a bit, then lets it snap back. He’s clearly surprised, even though he must have known it was coming. He releases it entirely and lets it spin in front of him. He grabs it and does it again. Then again.

And again.

“Yeah, it’s fun,” I say. “But look at the markings. Those are centimeters.

CEN-TI-ME-TERS.”

The next time he pulls the tape out, I point to the tape. “Look!”

He just keeps pulling it out and back again. I don’t see any indication that he cares about what’s written there.

“Ugh!” I hold up a finger. I go back to the lab and get another tape measure. It’s a well-stocked lab and no space mission would be complete without redundancy. I come back to the tunnel.

Rocky is still playing with the tape measure. Now he’s really having a ball. He pulls the tape out as far as he can, which is about a meter, then releases both the tape and the tape measure at the same time. The resulting recoil and snap-back makes the tape measure spin wildly in front of him.

“♩♪♫♪!!!” he says. I’m pretty sure that was a squeal of glee. “Look. Look,” I say. “Rocky. Rocky! Yo!”

He finally stops playing with the unintentional toy.

I pull some tape out on my tape measure, then point to the markings. “Look! Here! See these?”

He pulls his own out to approximately the same distance. I can see the markings on his are still there—they didn’t get baked off in the blistering Eridian heat or anything. What is the problem?

I point at the 1-centimeter line. “Look. One centimeter. This line. Here.” I tap the line repeatedly.

He holds the tape out with two hands and taps it with a third. He matches my tempo, but he’s nowhere near the 1-centimeter mark.

“Here!” I tap the mark harder. “Are you blind?!” I pause.

“Wait. Are you blind?”

Rocky taps the tape some more.

I’ve always assumed he had eyes somewhere and I didn’t recognize them.

But what if he doesn’t have eyes at all?

The airlock of the Blip-A was dark, and Rocky didn’t have any problem with it. So I figured he saw in frequencies of light I can’t see. But the tape measure has white tape with black markings on it. Any vision in any spectrum should be able to discern black on white. Black is the absence of light and white is all frequencies equally reflected.

Wait—this doesn’t make sense. He knows what I’m doing. He mimics my gestures. If he doesn’t have vision, how can he read my clock? How can he read his own clock?

Hmm…his clock has thick numbers. Like an eighth of an inch. And, thinking back, he actually did have some trouble with my clock. He needed me to tape it to the divider wall. When it floated an inch away he got upset. Just being close to the divider wasn’t enough. The clock had to be touching it.

“Sound?” I say. “Do you ‘see’ with sound?”

It would make sense. Humans use electromagnetic waves to understand our three-dimensional environment. So why couldn’t a different species use sound waves? Same principle—and we even have it on Earth. Bats and dolphins use echolocation to “see” with sound. Maybe Eridians have that ability, but on steroids. Unlike bats and dolphins, Eridians have passive sonar. They use ambient sound waves to resolve their environment instead of making a specific noise to track prey.

Just a theory. But it fits the data.

That’s why his clock numbers are thick. Because his sonar can’t perceive things that are too thin. My clock was a challenge to him. He can’t “see” the ink, but the hands are solid objects. So he knew about them. But the whole thing is encased in plastic….

I slapped my forehead. “That’s why you needed the clock pressed against the wall. You needed the sound waves bouncing around in it to get to you more easily. And the tape measure I just handed you is useless. You can’t see the ink at all!”

He plays with the tape measure some more.

I hold up a finger. He’s more focused on the tape measure toy, but he absently returns the gesture with one of his spare hands.

I fly back into the ship, through the control room, and into the lab. I grab a screwdriver and head farther down to the dormitory. I detach a storage panel from the floor. Simple aluminum sheet stock. Maybe one-sixteenth of an inch thick, with the edges rounded so we don’t cut ourselves. Strong, durable, and light. Perfect for space travel. I fly back to the tunnel.

Rocky has wrapped one end of the tape around one of his tunnel’s grab- handles and tied it in a somewhat crude knot. He hangs on to the dispenser with one hand and uses the other four to climb backward along the bars.

“Hey,” I say. I hold up my hand. “Hey!”

He stops playing with the tape measure for a moment. “♩♪♩?”

I hold up two fingers. Rocky holds up two fingers.

“Yeah. Okay. We’re in mimic mode again.” I hold up one finger, then switch to two, then back to one, and then finally three.

Rocky repeats the sequence, just as I hoped he would.

Now I put the aluminum panel between my hand and Rocky. Behind the panel, I hold up two fingers, then one, then three, then five.

Rocky holds up two fingers, then one, then all three. He brings in a second hand to hold up two more fingers for a total of five.

“Wow!” I say.

One-sixteenth-inch aluminum will stop pretty much all light. Some absurdly high frequencies can get through, but those frequencies would also pass right through me. So he wouldn’t see my hands. But sound travels through metals just fine.

That’s proof. He’s not using light to perceive what’s going on. It has to be sound. To Rocky, that metal plate is like a glass window. Maybe it muddles the image a little, but not much. Heck, he probably knows what the Hail Mary’s control room looks like. Why not? The hull is just more aluminum.

How did he see me out in space? No air in space. So no sound.

Wait. No. That’s a dumb question. He’s not a caveman wandering around in space. He’s an advanced interstellar traveler. He has technology. He probably has cameras and radar and stuff that translate data into something he can understand. No different from my Petrovascope. I can’t see IR light, but it can and then it shows it to me on a monitor with light frequencies I can see.

The Blip-A control room probably has awesome-looking Braille-like readouts. Well, I’m sure it’s way more advanced than that.

“Wow…” I stare at him. “Humans spent thousands of years looking up at the stars and wondering what was out there. You guys never saw stars at all but you still worked space travel. What an amazing people you Eridians must be. Scientific geniuses.”

The knot in the tape comes loose, recoils wildly, and smacks Rocky’s hand. He shakes the affected hand in pain for a moment, then continues messing with the tape measure.

“Yeah. You’re definitely a scientist.”

—

“All rise,” said the bailiff, “the United States District Court for the Western District of Washington is now in session. The Honorable Justice Meredith Spencer presiding.”

The entire courtroom stood as the judge took her seat.

“Be seated,” the bailiff said. He handed the justice a folder. “Your Honor, today’s case is Intellectual Property Alliance v. Project Hail Mary.”

The judge nodded. “Plaintiff, are you ready for trial?”

The plaintiff’s table was crowded with well-dressed men and women. The eldest of them, a man in his sixties, stood to answer. “We are, Your Honor.”

“Defense, are you ready for trial?”

Stratt sat alone at the defense table, typing away on her tablet. The justice cleared her throat. “Defense?”

Stratt finished typing and stood. “I’m ready.”

Justice Spencer gestured to Stratt’s table. “Counselor, where is the rest of your team?”

“Just me,” she said. “And I’m not a counselor—I’m the defendant.”

“Ms. Stratt.” Spencer took off her glasses and glared. “The defendant in this case is a rather famous intergovernmental consortium of scientists.”

“Led by me,” said Stratt. “I move to dismiss.”

“You can’t make motions yet, Ms. Stratt,” said Spencer. “Just tell me if you’re ready to proceed.”

“I’m ready,”

“All right. Plaintiff, you may begin your opening statement.”

The man stood. “May it please the court and ladies and gentlemen of the jury, my name is Theodore Canton, counsel for the Intellectual Property Alliance in this action.

“During this trial, we will show that Project Hail Mary has overstepped its authority in the matter of digital data acquisition and licensing. They have, in their possession, a gigantic solid-state-drive array upon which they have

copied literally every single piece of software that has ever been copyrighted, as well as every single book and literary work that has ever been available in any digital format. All of this was done without payment or licensing to the proper copyright holders or intellectual property owners. Furthermore, many of their technological designs violate patents held by—”

“Your Honor,” Stratt interrupted. “Can I make motions now?” “Technically,” said the justice, “but it’s irregul—”

“I move to dismiss.”

“Your Honor!” Canton protested.

“On what grounds, Ms. Stratt?” said the justice.

“Because I don’t have time for this bullshit,” she said. “We are building a ship to literally save our species. And we have very little time to get it done. It will have three astronauts—just three—to do experiments we can’t even conceive of now. We need them to be prepared for any possible line of study they deem necessary. So we are giving them everything. The collected knowledge of humankind, along with all software. Some of it is stupid. They probably won’t need Minesweeper for Windows 3.1, and they probably don’t need an unabridged Sanskrit-to-English dictionary, but they’re going to have them.”

Canton shook his head. “Your Honor, my clients don’t dispute the noble nature of the Hail Mary Project. The complaint is in the illegal use of copyrighted material and patented mechanisms.”

Stratt shook her head. “It would take a ridiculous amount of time and energy to work out licensing agreements with every company. So we’re not doing it.”

“I assure you, Ms. Stratt, you will comply with the law,” said the justice. “Only when I want to.” Stratt held up a sheet of paper. “According to this

international treaty, I am personally immune from prosecution for any crime

anywhere on Earth. The United States Senate ratified that treaty two months ago.”

She held up a second piece of paper. “And to streamline situations like this, I also have a preemptive pardon from the president of the United States for any and all crimes I am accused of within U.S. jurisdictions.”

The bailiff took the papers and handed them to the justice.

“This…” said the justice, “this is exactly what you say it is.”

“I’m only here as a courtesy,” said Stratt. “I didn’t have to come at all. But since the software industry, patent trolls, and everyone else related to intellectual property banded together in one lawsuit, I figured it would be fastest to nip this in the bud all at once.”

She grabbed her satchel and put the tablet inside. “I’ll be on my way.” “Hold on, Ms. Stratt,” said Justice Spencer. “This is still a court of law,

and you will remain for the duration of these proceedings!”

“No, I won’t,” said Stratt.

The bailiff walked forward. “Ma’am. I’ll have to restrain you if you don’t comply.”

“You and what army?” Stratt asked.

Five armed men in military fatigues entered the courtroom and took up station around her. “Because I have the U.S. Army,” she said. “And that’s a damn fine army.”

—

I browse through my available software while munching on a peanut-butter tortilla. I know that doesn’t sound tasty, but it is.

I’ve learned how to grip the lab chair with my legs so I don’t float off as I use the laptop. Turns out I have a bunch of laptops. At least six that I’ve found in the storage area so far. And they’re all connected to a shipwide Wi- Fi network. Handy.

If memory serves, I should have pretty much all the software lurking around somewhere on the ship. The trick is finding the one I need. I wouldn’t even know what it’s called. Fortunately, one of the books in the digital library is a list of software applications. So that helped.

Ultimately I find something that will work: “Tympanum Labs Waveform Analyzer.” There are all sorts of waveform-analysis software packages in my library. This one just has the highest reviews according to a 2017 computer magazine that reviewed waveform analyzers.

I install the software on one of the laptops. It’s pretty simple to use and has a plethora of features. But the one I’m most interested in is the Fourier

transform. It’s the most basic tool in sound-wave analysis and arguably the most important. There’s a lot of complicated math on how to make it happen, but the end result is this: if you run a sound wave through a Fourier transform, it will give you a list of the individual notes being played at the same time. So if I played a C-major chord and let this app listen to it, the app would tell me there’s a C, an E, and a G. It’s incredibly useful.

No more pantomime. It’s time to learn Eridianese. Yes, I just made up that word. No, I don’t feel bad about it. I’m doing a lot of things for the first time in human history out here and there’s a lot of stuff that needs naming. Just be glad I don’t name stuff after myself.

I launch Microsoft Excel on another laptop and tape the two laptops together back to back. Yes, I could just run both applications on one laptop, but I don’t want to switch back and forth.

I fly up through the ship and back into the tunnel. Rocky isn’t there. Hmph.

Rocky can’t just spend all day waiting around for me, but why don’t they have someone in the tunnel at all times? If my crewmates were still around, we would definitely rotate a watch or something. Heck, Ilyukhina would probably be camped out here nonstop and only leave when she had to sleep.

What if they are having different people in the tunnel? How do I know Rocky is just one person? I don’t know how to tell Eridians apart. Maybe I’ve been talking to six different people. That’s an unsettling thought.

No…that’s not it. I’m pretty sure Rocky is just Rocky. The ridges on his carapace and rocky protrusions on his hands are unique. I remember there’s an irregular craggy bit sticking up out of one of his fingers…yeah. It’s the same guy.

If you looked at a rock for several hours, and someone replaced it with a very similar, but slightly different rock, you would know.

Okay, so where is the rest of the crew? I’m alone because my crewmates didn’t make it. But Eridians have better technology, space-wise. Bigger ship, nigh-indestructible hull material. There has to be a crew in there.

Ah! I bet Rocky’s the captain! He puts himself at risk by talking to the scary alien. Everyone else stays back on the ship. That’s what Captain Kirk would do. So why not Captain Rocky?

Anyway, I have cool stuff I want to do and I’m impatient. “Yo! Rocky!” I yell. “Come here!”

I listen for any sounds of movement. “Come on, man! Your entire ranged sensory input is sound—I bet you can hear a pin drop a mile away! You know I’m calling you! Move your…whatever serves as your butt! I want to talk!”

I wait and wait, but no Rocky.

My guess is I’m a pretty high priority to him. So whatever he’s doing must be really important. After all, he’s got a ship to deal with. He probably needs to eat and sleep. Well, he has to eat, anyway—all biological organisms need to get energy somehow. I don’t know if Eridians sleep.

Come to think of it…sleep might not be such a bad idea. Out of the past forty-eight hours I’ve had a two-hour nap and nothing else. Rocky’s clock is still there, wedged between a grab bar and the divider wall. It’s ticking away as normal. It’s interesting that his clock only has five digits. By my math, it’ll roll over back to ℓℓℓℓℓ every five hours or so. Maybe that’s the length of an Eridian day?

Speculate later. Sleep is the priority. I set up a spreadsheet on my Excel laptop to convert from Rocky time to mine and vice versa. I want to sleep for eight hours. I enter the current time on Rocky’s clock, which is Iℓ IVλ, and have the spreadsheet tell me what that clock will say eight hours from now. The answer: Iλ+VVλ.

I hurry back to the lab to pick up a bunch of Popsicle sticks and tape.

Rocky can’t see ink, so I have to improvise.

I tape the sticks to the divider wall to let Rocky know when I’ll return: Iλ+VVλ. Fortunately, the symbols are mostly made of straight lines, so my little craft project should be good enough for him to read.

Interestingly, my return time has six digits. One more digit than Rocky’s clock shows. But I’m sure he’ll figure it out. If Rocky said “I’ll be back at thirty-seven o’clock,” I’d understand what he meant.

Before I hit the hay, I harvest a mini-camera from the lab’s vacuum chamber. It’s just a small wireless camera that talks to a portable LCD clipped to the chamber. I tape the camera up in the tunnel, pointed at the divider wall. I bring the readout screen with me to my bunk.

There. Now I have a baby-monitor setup in the tunnel. There’s no audio— the camera is for watching experiments, not chatting with people. But it’s better than nothing.

I tuck the bunk’s sheets and blankets in tight all around the oval mattress pad. I shimmy in between the tight bedding. This way I won’t just float around while I sleep.

My grand plans for communicating with Rocky will have to wait. I’m a little frustrated, but not for long. I conk out almost immediately.