“So, please forgive us, men, but we felt we had to keep it all under wraps. All we ask now is that you keep from chatting about it on the downlink, even if nobody's listening. Everyone agreed?” He looked around the galley. Each man had a thumb extended up, indicating agreement.
“Michael?”
“Everyone's got a thumb up over here, Roger.”
“Same here on Burroughs. Well, let's get to the rest of the briefing and orders.”
***
Two weeks before we fire off the first nuke! thought Mickey. I wonder how much of a shove we're going to get. He watched as the lasers cut old Eighty-two apart and the waldoes passed the slices into the vast fore end of the Perseus.
“I always wondered what we needed that comet for,” said Lima as he manipulated the waldo arms. “Seems it was just for drinking water and such.”
“Nah,” said Mickey. “Volatiles are life out here in space. Propulsion, fuel, reaction mass, chemicals for life. Just like on Earth, except there's so much water we never think about it. Space is dry.”
“So we're loading up the front with ice. Why not the back?”
“Eighty-two isn't just ice,” said Mickey.
“I know, I know. Ammonia, all kinds of other stuff in there. Even cyanide! I don't get how we're going to process all that.”
Mickey snorted. “Best possible way. Look, it's simple. Perseus is still rotating, just a whole lot slower, right?”
“Sure. About an eighth gravity at the inside shell. Less than the Moon. So?”
“How much in the center?”
“Zero,” said Lima. “But we don't want zero. We're already having problems with our bodies.”
“But zero is great for some processes. Like mass spectrometry.”
“Hang on, I've got a problem.” A chunk of the comet had broken free from the waldo arms and was spinning, the fragments of whirling ice reflecting sunlight in all directions.
“Need help?” asked Mickey. “I'll put out an alert.”
“Do it.” Lima devoted his whole being to the waldo controls.
“Alert, alert. We have fragmentation around the ice works. All space operations, check in,” called Mickey.
One by one, the crew who were outside in the dark checked in. Lima coped with the major fragments, while ignoring the smaller chunks of cometary ice.
“Howya doin',” Mickey asked quietly.
“On top of it. Just knowing when to say quit.” Lima looked up and smiled. “It's like those video games as a kid. 'Gotta get them all.'“
Mickey looked at the monitor, which showed the view from the waldo's cameras. Lima was manipulating the giant arms, reaching out to spear an ice chunk about a meter and a half long. With a short flick, the arm accurately tossed the fragment towards a massive chute which led into the fore end of the Perseus.
“In space, everyone's a perfect pitcher,” said Lima.
“Just let me know when you're done.”
“You can go ahead and let them know the danger is over,” said Lima. “I'm droning the area now.” He switched to a different set of controls.
On the monitor, the waldo arms ceased their thrashing, and an array of drones appeared, towing a mesh net behind them. Guided with expert puffs of steam instead of propellers, the net swept through the work area, snagging ice that was larger than the mesh. Soon, the work area was free.
“All right, we're done. Let everyone know.”
“The alert is canceled. Resume normal activities. Be alert for small ice fragments for the next hour. Out.” Mickey flipped a couple of switches. “Does this happen often?”
“Not too much. This time, I hit a boulder in the comet with the laser, and it exploded with just enough force to break apart the rest of the slice. Another three days of this, and old Eighty-two is history.”
“Just don't cut us up,” said Mickey. “We're still on the thing!”
“Hey, I live here, too,” said Lima. “My orders are to stop cutting fifty meters away from our spot and await further orders.”
***
Under the merciless glare of the cutting lasers, Lima sliced Eighty-two into small chunks, lobbed them over to the machinery perched just behind the massive prow of the Perseus, and reduced the once glorious comet to gravel. The processing machinery crushed the ice chunks to a moderate size, then fed them inside the front bubble of the Perseus. The ice gravel was melted, everything that was not water was centrifuged out. Ammonia, cyanide, and other noxious gasses were separated and compressed into tanks. The liquid water was left to slosh around inside the huge fore end. Under the slow but adequate rotation of the Perseus, it formed a lake that ringed the interior. Enormously tall waves circled the lake.
“Can't wait to go for a swim,” said Michael Standish, watching the lake on an inside camera. “But I guess that's not the plan, is it?”
Scott Acevedo looked his way. “Of course we're going swimming. One day. We just have to do a bit of taming. Finish processing Eighty-two, then figure out what goes where. We're definitely leaving a lake. Have to, in fact. How else are you going to farm fish?”
“Hmmm, yes. I just hope they'll grow in one-eighth gravity. So, go over the sequence again, please.”
Scott punched up the much-annotated document on his commpad.
“Reduce the comet, then make berths for the Burroughs and the Bradbury over on the Perseus. Transfer the ships, then grind up the last of Eighty-two. Bore out tanks in the wall separating the fore and aft ends of Perseus. Filter the water, pump the purified stuff into the tanks. Take the sludge, mostly sand and gravel, and make it into soil. It's sterile, but we'll fix that. Take all the ammonia and such, convert to fertilizer and trace nutrients. Start the farms. CO2 courtesy of Eighty-two. Run the atmosphere in here high with CO2 at first, helps the plants grow. When the plants have it back down to what humans can tolerate, then you can take your swim.”
“Sounds so easy, but I know it's not going to be that way.”
“Oh, I don't know. We're slowly pumping up the air pressure inside here. We're up to about a fifth sea level, about 200 millibars already. Pretty soon, all we'll need inside is an air mask and no pressure suit. Going to be nice to have room to run.” Scott frowned for a second. “Still wish we had more hands to help. We're getting pretty ragged here, boss.”
“I know. Roger and I agree, though. No new defrostings until after we're on our way.”
“We can take another four with our waste-handling systems now.” At a glare from Michael, Scott held up his hands. “I know, I know. I understand your reasons. Just saying it would help the workload.”
“Just wait until we get the ecosystem in the fore bubble working, then we're going to wake everyone up.”
***
“We're just not going to make the window, boss,” said Ivan. “We've got plenty of product, but we just can't get the machining working correctly.”
“Walk me through it,” said Jeff. “Tell me every step.”
“Well, we take out the thorium from the transport containers. It's in pellet form, a little marble about the size of a memory chip. McCrary was kind enough to have them already embedded in a thermoplastic backing. We've got a metal form that mimics the beryllium shell of the reactor's main vessel.”
“Come on, Jeff, this is going to take forever,” said Roger.
“You never know what will be crucial,” said Jeff. “McCrary taught me this. If you need to scoot, that's fine.”
“Yeah. Do you want me to send in Niall?” asked Roger.
“Hell no!” said Jeff. “We need someone to man the reactors. Lima and Harlan are busting tail turning out bomb parts, and Duane's running two reactors all by himself. I don't want him manning three.”
“Fine,” said Roger. “I'll expect your remedial plan by this evening. We must make that launch window.” He turned on his heel and loped out of the room.
“Uh,” said Ivan. “You want me to go on?”
“You were discussing a metal form,” said Jeff.
“Continue.”
“Right. Metal form. We heat it up, then mold the thermoplastic around the inside. Ensures that the thorium pellets are equally spaced around the core. We let them cook for a certain amount of time, depending on how hard we're running the reactor, usually a day or so. Then we strip out the sheets. A decent amount of the thorium has changed to protactinium. We pop the pellets free of the plastic, put them in a bin, and send them to the grinder. Plastic goes to a separate place for melting and reuse.
“Grinder's in a radioactive hot zone. Special area lasered out of the inside iron wall. Pellets are ground down, and the protactinium is chemically separated from the thorium—same process we use on the ships. Protactinium is then precipitated, melted, and poured into forms. Twenty-eight days later, half of it has turned to uranium-233, which is what we want. We could separate that out from the protactinium, or we could wait another three months, when we're down to one-sixteenth protactinium, and the rest is uranium-233. We're doing both, and making ingots with something like five percent protactinium in them. The time and manpower costs to purify the uranium any further is far too high for the gain in workability in the machine shop. At this point, we take the five percent ingots and machine them into the bomb parts.
“That's when we have our problems. The metal's not pure, it's an alloy of uranium and protactinium. It's also brittle: you could be going along, happy as a clam, the computerized lathe turning you a beautiful cylinder, then BAM, you're surrounded by flying pieces of radioactive metal.”
“But it's all glove-boxed,” said Jeff. “Does the box break?”
“Not at all, Jeff. We don't lose a milligram. But we have to gather up all the metal and send it back to be remelted. It sets back production, and we're way behind.”
“How does the ingot do the second time?”
“Second time's a charm—all of the two-timers make it through just fine.” Ivan scratched his head. “Maybe they're annealing or something. I don't know. I suppose you're going to want us to just melt and cast the ingots just before machining.”
Jeff sat back, staring at a point about three-quarters of the way up the wall.
“Jeff?”
He raised a finger. Wait. Expressions flitted across his lips. Compression of sudden thought, quirking as a train of thought ended in failure. Finally, a slow upturning of the corners of his mouth began. His eyes stared. He raised his finger again. The smile gathered momentum, climbing up his cheeks until it seemed that he was in danger of swallowing his earlobes.
“You're gonna love it,” he said. He turned to his commpad, hammering on the screen with his fingertips like he was racing a story deadline. “Young's modulus, niiice. We can do that. Now, what's the Poisson ratio for U-233? Hmmmm.” He pulled up a spreadsheet and filled the little boxes with arcane formulae. “Test,” he said. “Low. Good. High. Excellent. Now, for some specs.”
Ivan stirred. “Really? Sintering?” he asked. “But we're going to need to decontaminate the glove box and rearrange everything!”
“Hang on, not done,” said Jeff. He had another unlabeled area of the spreadsheet that he filled with formulae and numbers. “HA!” He saved the spreadsheet and initiated the intercom functions of the pad. “Now, for the acid test,” he said.
“Boss, got an answer,” he said into the commpad, “but I need you here to explain.”
“What are you proposing?” asked Ivan, as he punched his own commpad. “Going to take a lot of energy to sinter uranium.”
“I know. I'm only going to explain it once, though. Mind if I do this Socratically? You might pick up on something I miss.”
Ivan shrugged. “It's either this or head back to the hot box and try to lathe bomb parts.”
“What's the issue right now?”
Ivan shrugged. “We are having problems lathing the first-run uranium/protactinium ingots into bomb parts. The alloy is brittle and unexpectedly shatters during machining.”
“So, if we can't shave down a large mass,” Jeff began.
“We build it up from lots of smaller bits,” said Ivan. “That's why I mentioned sintering. But the amount of energy required to grind down the ingots, then fuse them together, is enormous.”
“Correct. Not to mention the dust hazard, which I don't take lightly. We don't have what you would call the best seals around on the Perseus. Some caulk, but I don't want a whole lot of dust any more than you do.”
“Okay, so how do we get the smaller bits to fuse to make a bomb part?” asked Ivan.
Roger Smithson bound into the room, then took a perch overlooking both men. “Yes?”
Jeff brought him quickly up to speed. “So, you see, the problem is this: either anneal the ingots before we machine them, which we just don't have time to perform, or figure out how to make bomb parts that don't require lathing, or something else.”
“What's something else?” asked Roger.
“Oh, I don't know,” said Jeff. “Something I haven't thought of, like filling up the end cup with water, and setting off the nukes in the water. There's a lot more high-pressure gas trying to get out of the cup, throwing us forward.”
“I thought we weren't going to do that. Something about the G-load being too much.”
“Plus, there's the hazard that the damn cup might shatter. Then we'd be in deep shit. So, we're not going to do it.”
The Commander shook his head. “Get to the point, will ya? I've got checklist items up the wazoo to finish, and I don't have time to play twenty questions.”
Jeff grimaced. “Right. Look, the current process is stick a blanket of thorium pellets in the reactor, cook 'em with a big neutron bath, then yank the stuff out and suck out the protactinium via chemicals. We take the precipitate, melt it in an ingot using a heating element, then lathe the ingot down to a bomb part. Some of the ingots shatter during machinery, causing a huge mess and stopping production.”
“Got it. What's the answer?”
“There's a process called explosive sintering. None of us picked up on it when Doctor Gulotta mentioned it several weeks ago, but it's going to save our bacon. You get a mass of metal powder, stick it in a mold, and hit it with a sudden blast of pressure, usually from an external explosion driving a piston into the mold. The stress crams the powder together, semi-melting the edges of the grains to each other. You get a solid-appearing part out of it.”
“Okay, downsides?”
“Biggest danger, and it's something we have to run tests on, is the explosive forming might give us a momentary critical mass.”
“Yeah, you're going to have to do that testing way the hell away from here, got it?” said Roger. “Plus, you better not be anywhere near it, either. We need you.”
“Trust me, I've got a huge survival instinct, boss,” said Jeff. “More downsides. A sintered part is more porous, so we might not have as much mass as we think, despite outside dimensions. So the bomb would have lower yield and less push than we want. Last downside—the powdered protactinium could escape the glovebox. In fact, the reason we went the melting route is to reduce the amount of precipitate powder floating around. Plus, we have to work in a vacuum.”
Roger waved his arm around the compartment. “Plenty of vacuum outside. Set up the forming machinery out there, but in a glovebox operated from inside. Keep the precipitate out of the living area.”
“Pretty much what I was thinking, boss. So, is it a go?”
“Yeah. Do it. How long to switch processes, and how quickly can you form bomb parts with the new process?”
“I was thinking that instead of doing either-or, that we do both. The bombs have a disk and rod arrangement. The discs are the ones that shatter when getting lathed, but the rods rarely do. Rods, on the other hand, would be a harder thing to sinter and get good uniformity throughout, whereas the discs can be sintered and the most critical dimension, the center part where the rod fits, can be assured with a simple iron-nickel molding during the sintering process.”
Roger waved his hands. “Enoug
h techno-talk! My head hurts. You guys know what you're doing. Go ahead and put it in place. I need those bombs ready to go within three weeks if we're going to make our deadline.” He turned and left the compartment.
“Let's get cracking,” said Jeff.
Collateral Damage
Hawaiian Islands, Earth, September 3 2084, 1444 HST
“We have reached our cruising altitude, and the captain has turned off the seatbelt sign. Sit back and relax as our flight attendants begin our complimentary beverage service.”
Sarah reached across the aisle to grasp Teddy's hand. The two newlyweds were on their way to a long-awaited honeymoon in Hawaii. So far, their flight across the North American continent from the Upper Michigan Peninsula was mostly stress free. The electric-hybrid engine was purring quietly as it sucked in the thin upper atmosphere, compressed it, ran it through a white-hot plasma torch, and shoved it out the back.
Sarah leaned in close to kiss Teddy, and he turned his face to meet her lips. The shock wave from the impact of a meteor blinded him and permanently deafened him. His shirt shredded where the three hundred millibar shock wave tried to peel it off of the young man. He had no idea what happened, but he knew he still held Sarah's hand.
The rest of Sarah had disappeared. The man in the seat behind her, unfortunately, had released his seat belt, so after the shock wave threw him back in his seat, the combination of the recoil of his seatback and the rarefaction zone left by the passage of the meteor straight through the aisle seat of row fifteen pulled him into the two-meter hole it tore through the airliner. He was not the only one to leave a suddenly not-so-perfectly-good airplane. Decompression was sudden, instant, and irresistible. Everything and everyone not tied down inside the aircraft was pulled to the sudden opening located at fifteen C and D. The reprieve was only temporary.
The pilot had time to register shock at the sudden impact before multiple alarms sounded on the annunciator panels inside the aircraft. He and the copilot reacted the same way: they let go of the controls, then reached behind them to pull on the oxygen masks and initiate oxygen flow. They looked at each other, verified that the other one was functional, and began the steep descent called for on the decompression checklist.
Dead Men Flying Page 21
