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.