Dead Men Flying

by Bill Patterson

  Jeff looked at it. “Maybe. So, that gives us something to hang onto and pull against. “What's to prevent it from pulling the cooled solid piece right out of the rest of the molten mix?”

  “So we cool more,” Lima said. “Hell, cool the entire end. You don't want it to expand anyway, right? Put three of these things into the asteroid, then slip over something that looks like a giant wheel rim, with the pipes as lug nuts. Cool the whole thing, and you'll never have to worry about the thing pulling out of the asteroid.”

  Jeff nodded. “I want to check this against Scott, but this looks really doable. That's just half of the problem, though.”

  Ramesh was unnaturally cool and calm as he slid a sketch of his own under Jeff's nose.

  “I know, the other part is simultaneously getting enough force to stuff the pipe in, while at the same time, blowing the iron away from it. Tell me if this would work.”

  The sketch depicted a section of pipe with holes in it. The holes were about the size of pencils, and set at a severe angle both axially and radially.

  “Why don't you tell me what you're trying to get at here,” said Jeff.

  “Simple enough,” said Ramesh. We pump liquid hydrogen down the pipe as we insert it. The hydrogen, exhausting through these holes, spins the pipe rapidly, and thrusts it forward. At the same time, once in the iron, the escaping hydrogen pushes the iron away from the pipe.”

  “You've got something around some of the holes?” asked Lima. “Control of some kind?”

  “Yes. If we shove the pipe in from here, any change in the density along the center path will result in the pipe changing direction. Then it's either sticking out of the side, or it kinks up in a big train wreck in the middle of the body. I figure if the hydrogen gas is pulling the pipe along, instead of pushing it, then we're more likely to get a straight run. Also, it's a pipe. It's hollow. Which means we can send a laser beam down the pipe to detect bending early.”

  Jeff had that sense of rightness that this solution would work, as well. There would have to be a lot of number crunching just to make sure, but this seemed to be more like it.

  “Looks like both of you came up with a workable solution. Lima, see if you can bring back the mirror to keep our baby warm while we work this out. I don't want the temperature going beyond fifteen hundred, and I sure as hell don't want it going below fourteen hundred. Anneal it, in a manner of speaking.”

  “No problem, boss,” he said. “Just gotta get to my board.

  “Spot him, Ragesh,” said Jeff. “I've got to go report to the Commander about this.”

  ***

  In the end, with another false start and plenty of tweaking, they got the pipe inserted for almost two and a half of the four kilometers necessary when it again became stuck and would no longer move. After rapid consultation among all the crew, Jeff made the decision to proceed with inflation. The pipe remained where it was, and torrents of hydrogen filled the rear sixty percent of the asteroid.

  “Problem, Jeff,” said Scott. “The differential angular momentum is going to rip off the front end.”

  “Ah, crap! All right, we gotta move superfast.”

  From inside the shelter, Ragesh performed a near miracle. In a blur of waldo motions, he stopped the hydrogen feed, disconnected all of the pipe segments except for the final one hundred and fifty meters, and racked all of the excess pipe. He reconnected the hydrogen feed to the stub sticking out of the asteroid and set the feed to remote.

  “Ready for the move, Jeff!”

  “Go, Lima.”

  Lima lifted the shelter in a broad curve that swept it around the swelling asteroid and repositioned it to the front of the asteroid. As they flew over the junction between the two sections, the two pieces of asteroid were threatening to pull each other apart. Orange and black striations spiraled from the inflating section to the original section.

  Lima, his mind on his piloting, turned to Jeff. “So, why's it doing that?”

  “The inflated section's like an ice skater with her arms out, the original one's got her arms tucked in,” replied Jeff.

  “They spin at different rates?” asked Ragesh.

  “Yup. Same angular momentum, though. Take something spinning and inflate it, the spin slows down. Deflate it, everything speeds up. Same amount of energy in the system. Dammit, I wonder what else I forgot about.”

  “We are in position,” said Lima.

  “Rivets ready,” said Ragesh. “Only got four scores on each pipe, though, and no washer.”

  Jeff looked at the darker red hue of the iron. “We have to go for it; the iron's cooling off. Set the rivets.”

  The process was a little bit tougher, because with the cooling, the iron had become more viscous. Jeff kept bumping a hand up against his faceplate, trying to tug on his chin, which he did whenever he was under stress.

  “Set,” said Lima. “How are you doing, Ragesh?”

  “Ready here. Fortunately, we've got enough pipe for that critical first section. Even had a spare insertion head and mirror for the laser. We can stick this in any time.”

  “Do it,” said Jeff. “Make sure we leave a good fifty to one hundred meters of iron up front. That will be taking a lot of abuse, I want it built up.”

  Ragesh once more worked the waldo circuits like a coke-addled demon. “I snagged a few bottles of hydrogen, but we'll have to get some more of it.”

  “How much?” asked Jeff.

  “I can get us in about a kilometer, but after that, we're dead. No inflation possible with what we have.”

  “I'll get someone else out here to bring it over. In the meantime, get cranking.”

  While Ragesh worked the insertion sequence again and Jeff was on the radio, Lima had time to think. One question immediately presented itself: how could they figure out how thick the wall was between the two sections of the asteroid? He took a stylus and drew on a tablet, outlining the problem.

  “Hey, Ragesh,” Lima said. “Got any spare brain cells I can borrow? I've got a problem.”

  “Seems to be the theme today,” said Ragesh. “This is mostly routine now, but I still have to pay attention. What's on your mind?”

  “How do we know how far in you are?”

  “Simple, I'm counting pipe segments.”

  “Right. But have we ever measured the asteroid precisely?”

  “Sure,” said Ragesh, after a brief interruption to screw on more pipe. “Forty-two hundred meters.”

  “But that was cold. How big is it now?”

  “Right, the thing expanded as it heated up, but might have gotten shorter when the back half inflated. Damn. Uh, not certain.”

  “That's what I thought. Consider, we've been lucky—the pipe in the back still reflects a laser signal. So we put a rangefinder circuit in it, and we get the length to a centimeter or so.”

  “Close enough. Then what?”

  “Use another laser to measure the distance from the end of the fill pipe to the rear surface of the asteroid, then take that same laser and measure along the asteroid to our rig here, then repeat the process down to the end of that pipe of yours. We'll be able to tell to within a meter or so just how much of a wall separates the two sections.”

  Ragesh thought it over while he manipulated the pipe segments. “Sounds like it could work. Gotta make sure it's all at right angles. You're making the largest set of calipers ever.”

  Lima gave him a thumbs up. “I'll talk with Jeff when he finishes with the hydrogen delivery.”

  ***

  The asteroid stretched and swelled under the tender ministrations of Ragesh, Lima, and Jeff. As inflation proceeded, the semi-liquid membrane between the two sections thinned and stretched along with their inflations.

  It wasn't perfect, of course. Nothing in nature ever was. The asteroid finally cooled into a hollow cylinder about 3800 meters long by 1100 meters in diameter, with walls that averaged fifty meters thick. The thinnest was over one particular weak spot in the rear section, but even there, the
small blister sported thirty-five-meter-thick walls.

  The prow was some-hundred-meters-thick overall. The feed pipes in each end remained, as did the 'rivets', although their blind ends remained embedded in solid iron-nickel rock.

  To hasten the cooling of the Perseus, the crew positioned the huge cylindrical mirrors between the sun and the asteroid, shadowing the asteroid from the star while dispersing the radiating metal's heat into space. Bluing gas displaced the superheated hydrogen gas used for inflation. One week later, Jeff released a free-flying drone with camera for an interior survey of the inner walls.

  Once they obtained a suitable level of bluing in the forward chamber, Jeff pumped steam into the asteroid from a small delivery line run down the center of the blow pipe. Superheated steam returned under pressure through exhaust vents drilled next to the blow pipe's entrance hole. From there, the steam flowed into network of pipes set in the center of the mirrored hemispheres that Lima had cut off of the hot dog so long ago. This was a highly efficient radiator, sending a beam of intense infrared energy out into space and cooling the steam. By the time the steam got through the labyrinth and back to the head of the blow pipe, the steam had condensed to water, ready to begin the cycle again.

  In less than three weeks, the asteroid had cooled to the extent that astronauts could approach it.

  ***

  The temperature of the asteroid was well below the Curie point, and iron would once again react to magnetic fields. The astronauts resumed using magnets to hold themselves and their tools tight to the body of the Perseus. The most important tool that was held to the surface was an ultraviolet cutting laser. The laser bit slowly into the skin of the asteroid. After all, it had fifty meters of metal to cut through.

  “I still don't know why we didn't do this before we finalized the inflation,” said Harlan, monitoring the cut from the shelter. “We could have pinched off a blob of iron, spun it into a disk, and let that cool.”

  Scott Acevedo looked at him in amazement. “With what?”

  “What do you mean with what?” retorted Harlan. “We're doing science fiction stuff right here already. I bet if we just asked the question, Jeff or Ragesh or Mickey or someone would come up with the answer in a minute. I dunno, supercritical hydrogen gas or something like that.”

  Scott shook his head. “Nope. Besides, we need to cut the entire back end off this thing. Perseus will be an airtight cylindrical iron bubble on top of an open tin can.”

  “Now, I seriously don't get that,” said Harlan. “What possible sense does that make?”

  “Jeff and the Commanders have a plan. I hear they're going to let us all in on it sometime in the next week. For now, just make sure we're not fouling the laser.”

  Harlan snorted. “Not gonna happen. We got smart on this one. Biggest issue on these jobs is the vaporized stuff blasting out of the hole and condensing on the aperture of the laser, right? Builds up between pulses, all the energy goes into vaporizing the condensed iron, laser goes boom, right? Well, Lima and I worked out a rig. Laser is out of the way, and the beam bounces off a mirror on its way down the hole. Any vapor condenses on the mirror. It gets fouled too much, we've got a mechanism to kick it out of the way and there's another perfect mirror right behind it.

  “Lima made me a hundred of these, and is making a lot more. The laser is going to be just fine. And it's gonna be boring here.”

  “How deep is the first hole?”

  “Uh. I think we're hitting thirty-one meters.” Harlan peered at the control board. “About nineteen or so to go.”

  “Let's see if we can at least break through here before we break for lunch.”

  “I canna change the laws of physics, Captain!” said Harlan, in mock panic.

  Scott gave Harlan a raspberry. “Gotta work on that Scottish accent.”

  It took another day to penetrate the iron wall and reach the center of the asteroid. Then another day until a beam emerged from a spatter cone on the other side of the asteroid. After that, Scott and Harlan set up a second laser at the far side. Together, the two lasers slowly cut a line between each other, like a prisoner with a string and brick dust, sawing through the bars on a prison window.

  ***

  “Any minute now,” said Harlan. “I can see the cut of the other laser about a centimeter ahead.”

  Scott peered over the board in from of him. “All right, when the final bit is vaporized, I want to pull us back five meters and stop. Then we turn off the lasers.”

  “Uh, Scott, the laser turns off automatically if there's any movement of the base. Since we've got a tire on the far side of the cut, that will register.” Harlan shrugged. “It was a failsafe put in there in case the magnetic tires didn't hold. Is it a problem?”

  “No, no. Go ahead with the pullback, though,” said Scott. “We'll have to wait a few minutes for the edges to cool before we go in.”

  There was a barely perceptible shudder as the laser severed the last piece of metal tying the end plate onto the asteroid. The shelter, grasping the three-pipe anchorage, thrust backwards, slowly pulling the much larger chunk of iron with it.

  They had cut off the fully solid end of the asteroid, and about fifty meters of hollowed out chamber with it. Next, they lathed down the end plug, some fifty meters of solid iron, with the lasers, carefully cutting away a torus of iron, so that the end plug now resembled a rather squat cup sitting atop a cylinder of iron. This left a donut, or torus, of iron looking like a manhole cover with the center cut out. Scott and Harlan now laser-welded the torus over the open cup so it had a partial lid on it.

  They carefully rotated the entire assembly one hundred and eighty degrees and tucked it back onto the asteroid, the cylinder making a good, tight fit onto the end of the asteroid. The work took about two weeks, mostly laser work. The biggest question, though, was would it fly?

  ***

  Commander Smithson drifted at the nose of the asteroid, a speck against its immense girth. He held a precious bottle of champagne in his hand.

  “It's been a very long, hard road, men, but we're finally able to plan for our return journey. First, I have an ancient tradition that must be observed. Commander Standish?”

  Commander Standish, inside the Bradbury, cleared his throat. “Since time immemorial, ships have been christened with a bottle of spirits in order that they may give good and faithful service. The task of breaking the bottle over the bow of the ship and launching it on its way is usually performed by the spouse of the senior dignitary. Commander Smithson is our senior dignitary, but he appears to have left his spouse at home. No matter, men have christened ships quite often in the past.

  “And so, we christen this vessel Perseus. May it be our armor and shield against our journey ahead.”

  Commander Smithson raised his arm and smashed the bottle against the pitted iron prow of the asteroid. The liquid inside foamed, froze, and began to sublimate in the vacuum of space.

  “Okay, fun's over,” Roger said. “Everyone, please gather in the galley of your ship. Commander Standish and I have some orders for the next week.”

  ***

  “So, you see, there's no other way to move this enormous hunk of metal out of this orbit and down to Earth, nor to control it once we get there, with anything other than a nuclear bomb,” said Roger.

  The crew barely reacted. Roger looked at Michael with surprise.

  Doctor Aaron Gulotta laughed. “I'm sure some of the crew knew, but nobody told me a thing. But come on, Roger. We're spacemen! That means not just that we've learned how to live in space, but that we're a cut above the average Earthman. Most of us grew up reading science fiction. Perseus is an inflated asteroid. All kinds of authors used the concept over the years.

  “If they weren't moving these things around with some kind of weird science engine, then they were using small nukes to do it. Hell, NASA was talking about these kinds of systems back in the 1960s.”

  “So, ah, nobody said anything?” asked Roger. “You figured th
is out on your own?”

  Again, the laugh from the doctor. “Of course! All that thorium the Moon sent—way more than any conceivable need. Even if we ran the reactors at max, there's no chance we'd go through a tenth of the load. The rest had to be for some other purpose. I was betting on bombs once I saw what you were doing with the back end of the asteroid. That cup-like thing, especially with the lid, is the perfect bomb-chamber. It's not much of a lid, true, but it's perfect to delay the emptying of the cup a few more seconds, so more of the bomb's energy translates into forward momentum.”

  Roger kept peering at him.

  “Plus, I had to treat what had to be radiation injury a couple of times. Uranium isotopes leave different kinds of radiation traces, if you know what to look for. Lots of U-233, and no U-234, so I figured you guys were making bomb components. I wondered why you never did explosive powder forming for your bomb parts instead of casting the metal then carving it.”

  Roger looked around the galley. “Michael, is it much the same over on the Bradbury?”

  “Pretty much. I think we owe the men an apology.”

  Roger nodded. “I apologize to the crew for our security measures. Let me explain why we kept this item under wraps the way we did.”

  He talked about the cautions that came from McCrary, as well as his own experiences in discussing the peaceful uses of nuclear energy to various audiences.

  “If this propulsion strategy got out to Earth, we knew that we'd face a storm of criticism when we got home. We're hoping we can use the nukes where nobody on Earth will be able to detect them. I should have let you men in on the secret, but I couldn't trust the news not getting out on our downlink. Sure, it's encrypted, but who knows if that's still secure?