by Andy Weir
I looked at the silver dome of the Sanchez smelter bubble. Again.
My previous visit had been just six days earlier, but it seemed like forever ago. Of course, things were a little different this time. There’d only be one harvester out there doing its thing. That’s okay, I wasn’t after the harvester, anyway. That was old news.
Dale brought us up to the edge of the bubble, did a three-point turn, and pointed the rear of the rover at the wall.
“Distance?” he asked.
I checked my screen. “Two point four meters.” Proximity readouts are a frilly feature for cars on Earth, but critically important for lunar rovers. Crashing your pressure vessel into things is bad. It can lead to unscheduled dying.
Satisfied, Dale engaged the physical brake. “All right. Ready to suit up?”
“Yup.”
We climbed out of our chairs and crawled to the rear of the vessel.
We both stripped down to our underwear. (What? I’m supposed to be demure around the gay guy?) Then we put on our coolant garments. The daylight outside could boil water—EVA suits need central cooling.
Next came the pressure suits themselves. I helped him into his and he helped me into mine. Finally, we did pressure tests, tank tests, readout tests, and a bunch of other shit.
Once all the checks were done, we prepared to egress.
The rover airlock could fit two, though it was snug. We squeezed in and sealed the hatch.
“Ready for depress?” Dale asked via the radio.
“Pretty depressed, yeah,” I said.
“Don’t joke around. Not with airlock procedures.”
“Sheesh, you really suck the air out of the room, you know that?”
“Jazz!”
“Copy, ready for decompression.”
He turned a crank. Air hissed from the chamber to the vacuum outside. No need for a high-tech pump system. It’s not like oxygen was in short supply; thanks to smelting, Artemis had so much we didn’t know what to do with it all….
For the moment, anyway (evil sardonic laugh).
He spun the handle, pushed the door open, and stepped out. I followed.
He climbed the ladder to the rover’s roof and unhitched the rigging. I went to the other side and did the same. Then, together, we lowered the modified air shelter to the ground.
Weighing in at five hundred kilograms, it took both of us to make sure it came down gently.
“Try to keep dust off the skirt,” I said.
“Copy.”
Dad had done a number on the shelter. You could hardly recognize it. It had a large hole in the rear with a half-meter-wide aluminum skirt all around it. It looked like an engine bell. Some might say putting a huge hole in a pressure vessel is a bad idea. I have no rebuttal.
I clambered back up to the rover’s roof and collected my welding gear. “Ready to receive?”
He positioned himself below me and held up his arms. “Ready.”
I handed him the tanks, torches, tool belt, and other accessories I’d need for the job. He placed each on the ground. Finally, I pulled a huge bag out of its dedicated container.
“Here comes the inflatable tunnel,” I said. I shoved it off the roof.
He caught it and laid it on the ground.
I hopped off the roof and landed next to him.
“You shouldn’t jump down that far,” he said.
“You shouldn’t fuck other people’s boyfriends.”
“Oh, come on!”
“I could get used to this new relationship we have,” I said. “Help me get all this crap over to the bubble.”
“Yeah, yeah.”
Together we carried or dragged everything to the wall.
The arc of the dome, broken into two-meter triangles, was vertical at ground level. I selected a reasonably clean triangle and dusted it off with a wire brush. There’s no weather on the moon, but there is static electricity. Fine lunar dust gets everywhere and sticks to everything with the slightest charge.
“Okay, this one,” I said. “Help me move the shelter into position.”
“Copy.”
Together, we hoisted the air shelter and shuffled it over to the dome. We pressed the aluminum skirt against the shiny wall then set the shelter down.
“Goddamn, Dad’s good,” I said.
“Jesus,” Dale said.
He’d done an absolutely perfect job on the skirt. I mean, okay, he just had to make the point of contact with the wall flat, but holy hell. There was less than a millimeter of gap between the skirt and the wall.
I brought up my arm readout, which was basically just a fancy external screen for my Gizmo. The Gizmo itself was safely inside the suit with me (they’re not made to handle the rigors of the outdoors). I tapped a few buttons and made the call.
“Yo, Jazz,” said Svoboda. “How’s tricks?”
“So far, so good. How’s the camera feed?”
“Working perfectly. I’ve got your suit cams on the screens.”
“Be careful out there,” came Dad’s voice.
“I will, Dad. Don’t worry. Dale, you getting the phone audio?”
“Affirm,” said Dale.
I walked back to the skirt and faced it so the helmet cam would point at it. “Good skirt alignment. Like…really good.”
“Hmm,” said Dad. “I see some gaps. But smaller than the bead you’ll be making. Should be fine.”
“Dad, this is some of the best precision I’ve ever—”
“Let’s get to work,” he interrupted.
I dragged the oxygen and acetylene tanks to the site and fixed the torch head.
“All right,” Dad said. “Do you know how to start a flame in a vacuum?”
“Of course,” I said. No way in hell I would admit I learned it the hard way just a few days ago. I set the oxygen mix very high, sparked the flame, and got it stabilized.
When I’d worked over the harvesters earlier I’d done very rudimentary joins. I just needed it to hold the pressure in long enough to blow up. These joins would be a lot more complicated. The job would’ve been trivial for Dad, but he didn’t know anything about EVAs. Hence our teamwork.
“Looks like a good flame,” Dad said. “Start at the crown and let the bead puddle downward. Surface tension will keep it aligned with the gap.”
“What about the airflow pressure?” I said. “Won’t it blow droplets into the skirt?”
“Some, but not much. There are no eddy forces around the flame in a vacuum. There’s just the pressure of the flame itself.”
I held a rod of aluminum stock to the top of the skirt and set the flame on it. It was awkward in my EVA suit, but not too bad. A bead of molten metal formed at the tip and dribbled down. Just as Dad predicted, it wicked along the gap and filled the crack.
By habit, I brought the flame down to the fill site to keep the bead molten.
“No need for that,” Dad said. “The metal will stay liquid longer than you expect. There’s no air to convey the heat away. Some gets lost through the metal, but the state-change soaks up most of the energy. It can’t radiate too far.”
“I’ll take your word for it,” I said. I returned the flame to the aluminum stock.
Dale stood a few meters away, ready to save my life.
And there I was again. Melting metal while in a vacuum. If a blob melted my EVA suit, my life would be in Dale’s hands. If I sprung a leak, he’d have to haul me into the rover airlock. I wouldn’t be able to do it myself because I’d be too busy dying of asphyxiation.
Bit by bit, I worked my way around the perimeter of the skirt. Dad told me when I went too fast or slow. Finally, I got back to the start of the seam.
“Whew,” I said. “Time for a pressure test.”
“No it isn’t,” Dad said. “Run another line. All the way around. Make sure you completely cover the first weld.”
“Are you kidding me?!” I protested. “Dad, that weld is solid.”
“Run another line, Jasmine,” he said firml
y. “You’re not in any hurry. You’re just impatient.”
“Actually I am in a hurry. I have to get this done before the Sanchez shift change.”
“Run. Another. Line.”
I groaned like a teenage girl (Dad really brought that out in me). “Dale, hand me more rods.”
“No,” Dale said.
“What?”
“As long as you have that torch in your hand, I won’t take my eyes off you, I won’t be more than three meters away, and I won’t have anything in my hands.”
I groaned louder.
It took another twenty minutes, but I ran another seam around the skirt under Dad’s watchful eye.
“Well done,” said Dad.
“Thanks, Dad,” I said. He was right. I’d done a good job. Now I had an air shelter perfectly welded to the smelter bubble’s hull. All I had to do was cut a hole in the wall from inside the shelter and I’d have a ghetto airlock.
I set the torch down on a nearby rock and spread my hands at Dale. Now that I met his stringent requirements for safety, he ambled toward the inflatable.
The inflatable was the same kind I’d helped set up during the Queensland Glass fire—an accordion tube with a rigid airlock connector at each end. He and I each grabbed a hoop and backed away from each other. I headed toward the newly welded air shelter while Dale went to the rover.
I loaded all my welding equipment and tanks into the tunnel, then connected my end of it to the air shelter. Then I joined Dale and we both climbed into the rover airlock. Together we pulled the tunnel’s other connector into place.
I stared down the tube toward the still-sealed air-shelter hatch.
“Time to test it, I guess,” I said.
He reached for the valve. “Keep on your toes. Just ’cause we’re in EVA suits doesn’t make us safe. If we misconnected the tunnel, we could be in for an explosive decompression.”
“Thanks for the tip,” I said. “I’ll be ready to jump out of the way if a pressure wave moving the speed of sound comes at me.”
“You could be less of an ass.”
“I could,” I said. “But it’s not likely.”
He turned the valve and a foggy plume of air rushed in from the pressurized rover compartment. I checked my suit readouts and saw we were up to 2 kPa—about 10 percent of normal Artemis pressure.
An alarm blared from inside the rover.
“The fuck is that?” I said.
“Leak warning,” Dale said. “The rover knows how much air it should take to fill the airlock, and we’ve gone way past that. We’re filling this whole tunnel.”
“Problem?”
“No,” he said. “We’ve got plenty in the tanks. Way more than we need. Bob saw to that.”
“Nice.”
Slowly, the tunnel inflated. It held pressure perfectly, of course. This was exactly what it was designed to do—connecting one hatch to another.
“Looks good,” Dale said. He turned the hatch crank and opened the rover’s inner airlock door. He climbed into the main compartment and settled into the driver’s seat. The rover was designed to accommodate a driver with or without an EVA suit.
He checked the control panel. “Twenty point four kPa, one hundred percent oxygen. Good to go.”
“Here goes nothing,” I said. I popped the vents of my EVA suit. I took a few breaths. “Air’s good.”
Dale joined me in the connector and helped me de-suit.
“J-J-Jesus.” I shivered. When you release pressurized gas it gets cold. By filling the tunnel from the rover’s high-pressure tanks, we’d made a goddamned meat locker.
“Here.” Dale handed me my jumpsuit. I put it on faster than I’d ever put on clothes before. Well…second fastest (my high school boyfriend’s parents came home earlier than expected one day).
Then he handed me his own jumpsuit. He was a big enough guy that his clothes fit over mine easily. I didn’t even argue. I leapt right in. After a minute, I warmed up to something bearable.
“You all right?” he asked. “Your lips are blue.”
“I’m okay,” I said through chattering teeth. “Once I fire up the torch, it’ll be plenty warm in here.”
I pulled my Gizmo out of its holster on the EVA suit, then popped an earbud into my ear. “You still there, guys?”
“We’re here!” said Svoboda.
A thought struck me. “Did you watch me strip on Dale’s video feed?”
“Yup! Thanks for the show!”
“Ahem,” said Dad’s voice.
“Oh, relax, Mr. B,” said Svoboda. “She kept her underwear on.”
“Still…” Dad protested.
“All right, all right,” I said. “Svoboda, consider that payment for all the favors you’re doing me. Now, Dad: Any prelim advice on this cut?”
“Let’s get a look at the material.”
I walked down the tunnel toward the air shelter and Dale followed close behind. I glanced back at him. “You going to be on my ass like that through the whole thing?”
“Pretty much,” said Dale. “If there’s a breach, I’ll have to get your un-suited body down the tunnel and into the rover. I’ll have three or four minutes before you get permanent brain damage. So yeah. I’m going to hang nearby.”
“Well, don’t get too close. I need elbow room to work and you don’t want the flame anywhere near your suit.”
“Agreed.”
I turned the air-shelter valve and let air from the tunnel into the shelter. We listened to the hiss closely. If it stopped, that meant the skirt weld was airtight. If it just kept hissing that meant there was a leak and we’d have to go back out there and find it.
The hiss grew more and more quiet, eventually coming to a stop. I cranked the valve open all the way and there was no change. “Seal’s good,” I said.
“Well done!” Dad exclaimed over the radio.
“Thanks.”
“No, seriously,” he said. “You made a three-meter-long airtight weld while wearing an EVA suit. You really could have been a master.”
“Dad…” I said, a note of warning in my voice.
“All right, all right.”
He couldn’t see my smile, though. It really was a hell of a weld.
I cranked the hatch open and stepped in. The metal tube was freezing cold. Water condensed on the walls. I gestured Dale to the front. He turned on his helmet lights and got close to the weld site so Dad could see it through the camera.
“The inside edge of the weld looks good to me,” I said.
“Agreed,” said Dad. “Make sure Mr. Shapiro stays nearby, though.”
“I’ll be right behind her,” Dale said. He stepped back into the connector.
I craned my head back to Dale. “Are we sure the pressure in here is exactly twenty point four kPa?”
Dale checked his arm readouts. “Yes. Twenty point four kPa.”
We had pressurized to 20.4 kPa instead of Artemis’s standard 21. Why? Because of how double-hull systems work.
Between the two hulls, there’s a bunch of crushed rock (you knew that). But there’s also air. And that air is at 20.4 kPa—about 90 percent of Artemis pressure. Also, the space between the hulls isn’t a giant empty shell. It’s partitioned into hundreds of equilateral triangles, two meters on a side. Each of those compartments has a pressure sensor inside.
So outside there’s vacuum, between the hulls there’s 90 percent Artemis pressure, and inside the bubble there’s full Artemis pressure.
If there’s a breach in the outer hull, the compartment’s air will leak out to the vacuum outside. But if there’s a breach in the inner hull, the compartment will be flooded with higher-pressure air from inside the bubble.
It’s an elegant system. If the compartment pressure goes down, you know there’s a leak in the outer hull. If it goes up, you know there’s a leak in the inner hull.
But I didn’t want a hull-breach alarm going off in the middle of my operation, so we made damn sure our air pressure matched the insi
de-hull pressure.
I made a quick inspection of my torch nozzle to make sure it hadn’t warped in the temperature changes it had just been exposed to. I didn’t see any problems.
“Dad, according to the specs, this will be the same as a city bubble hull—six centimeters of aluminum, a meter of crushed regolith, then another six centimeters of aluminum.”
“All right,” said Dad. “The initial breakthrough will be messy because of the thickness of the material. Just stay with it and try not to wobble. The steadier your hand the faster it’ll breach.”
I pulled the oxygen and acetylene tanks into the shelter and prepped the torch.
“Don’t forget your breather mask,” said Dad.
“I know, I know.” I’d completely forgotten. Oxyacetylene fills the air with toxic smoke. Normally it’s not enough to matter, but in a confined pressure vessel you need your own breathing apparatus. Hey, I would have remembered once I started coughing uncontrollably.
I reached into my duffel and pulled out a mask. The attached air tank had a little backpack rig to keep it out of the way. I put it on and took a few breaths just to make sure it worked. “I’m ready to fire up. Any other advice?”
“Yes,” he said. “The regolith has a high iron content. Try not to linger in one place for too long or it might clump up around the cut site. Too much of that and you’ll have a very hard time pulling the plug out.”
“Got it,” I said.
I put on my welding helmet and fired up the torch. Dale took a step back. However fearless EVA masters may be, there’s still a deep, basic instinct in all humans to avoid fire.
I grinned. Finally I’d get some revenge. Time to cut a hole in Sanchez’s gut.
I adjusted the gas mixture until I had a long flame. I picked a spot on the wall, dug in, and held the torch as still as I could. The massive heat plus the ready supply of oxygen dug away at the metal, boring a deeper and deeper hole.
Finally, it broke through. I can’t tell you exactly how I knew. I just knew. Maybe it’s the sound? The sputter of the flame? Not sure. In any event, the cut had begun.
“No airflow in or out,” I said. “Looks like a pressure match. Good job, Dale.”
“Thanks.”
