by Garon Whited
On duty, it’s always someone’s turn to teach his or her job to everyone else. For example, I’ve racked up many more hours of simulation time in the Luna, and now feel confident that if I ever land her, I can probably put her back together. Down in the reclamation and recycling system, I really don’t want to ever have to use the emergency waste purge Julie showed us unless I’m in a spacesuit. It strikes me as messy. I don’t think anyone minds Anne’s secondary job—hydroponics is the gentleman farmer’s way of growing things—but nobody here is going to become a doctor of space medicine in less than ten years. If then. But I now feel confident that I can tie off a bleeding artery without fumbling it—much.
We also keep an eye on Earth. It’s clouded up a lot, worse than the smog ever was, although the static from atmospheric radiation has dropped off by almost ninety percent. The thermal imager in the observatory says the place is warmer than usual—greenhouse gases, Anne says. She’s the closest thing to an ecologist we have. But we can see the craters through the cloud cover by using thermal and gamma-ray telescopy.
London. Paris. Rome. New York. Washington—most of the Eastern Seaboard, actually, and a lot of the Western. Capitols around the world. Cities of a million or more people. Almost all of Japan. Even South America and Africa got smeared. Hawaii is still burning, along with a lot of forests, rainforests, and grasslands. The world looks like a paper target for a shotgun—and it’s on fire.
I think it’s a good thing we can feel distant from the destruction. If we were still in the wailing-for-the-loss-of-life stage, we’d go crazy. If we aren’t already.
* * *
The one-em-cee honked to life as I was lining up a shot on the polished-rock surface of the pool table. Julie was on watch in the control room; it was her voice that blared out the announcement.
“All hands! Radio signal from Earth! I repeat: All hands! Radio signal from Earth!”
We practically flew down the corridors. I know I left the deck at least once to bounce off a wall in order to make a turn; Kathy did it ahead of me with her usual impossible grace. It looked like a good way to avoid having my feet go out from under me again. Trust a pilot to ignore minor details like the floor.
Anne shouted, “Showoffs!” at us; that’s why I remember it. Well, maybe I was showing off. A little.
We took our stations in central control and listened.
“—surfaced off the coast of Florida. It doesn’t matter now. Whatever it is, it incubates for about four days, then hits fast. I’m feeling weak and shaky, but I’d rather be shot than go like the rest of the crew.”
“Captain?” Julie asked. “May we respond?”
“Give me the mike.” Julie handed it to him. “This is Captain Carl Hughes, Commanding Officer of Luna Base One. Discontinue radio transmission; you are targeting yourself and those around you for orbital weapons platforms.”
We waited for our signal to reach him and for him to respond. A second and a half to get there, then another second and a half for his signal to reach us…
“Thank God! It’s not just a recording! I’m not the last! Thank God!”
Captain Carl keyed his microphone and was about to speak, but the voice went on.
“Captain, sir, I’m Ensign Parker of the Swordfish, Independence-class nuclear submarine. Be advised that a virulent, deadly disease is on the loose. When you come back down, stay sealed up! It takes about four days before you know you’ve got it, and then it starts to eat away your muscle control. It gives you the shakes, and then you’re paralyzed in six to twelve hours, mostly. People die when their hearts and breathing finally stop. I’ve been getting worse, but I’ve lasted a long time—nearly twelve hours since the shakes and weakness started.”
“Contact!” Kathy announced, working at her terminal. “Missile launch detected, projected impact near eighty-three west by twenty-eight north—maybe in the Gulf, near the coast of Florida. Time to impact… uncertain, maybe five minutes; missile still accelerating. Missile launch response time, two minutes plus. Launch platform orbit being computed.”
“Ensign!” the Captain snapped. “There is a missile homing on your transmission! Dive! Get out of there!”
“The disease is airborne; we haven’t had any—” he paused, listening to the delayed transmission. “A missile? Good…
“Captain, I can’t dive. We’re in the harbor—I’m in the harbor—at what used to be Tampa. I only just barely got the boat stopped and surfaced. There’s no one left aboard but me, sir, except for the bodies. Now I can’t even stand up. If I weren’t wearing a headset, I don’t think I could even key a mike. I’m sorry, sir.”
Captain Carl nodded, even though the sailor couldn’t see it. “All right, son. I was hoping you could stay with us a little longer. Are you sure you want a missile?”
“I’m sure. I’ve seen what happens… I’ve seen my shipmates die. It’s lethal, sir.
“All right, son. All right. It’s your choice.”
“It’s hard to talk, sir. I have to think about breathing—it doesn’t work on its own anymore. I keep expecting my heart to stop. Any second now. I don’t mind dying from enemy fire. At least I’m taking out one of their missiles, right? That’s one less shot they have for anyone else, isn’t it?” There was the sound of labored breathing for a moment. “How long have I got to wait for the nuke?”
Kathy made sure her own mike was off and whispered, “Impact in three minutes, eight seconds.”
“Keep on that satellite orbit,” the Captain whispered back. Then, to Ensign Parker, “About four minutes, son. You can hang on that long. I’ll stay on with you until then. Can you tell me how your ship got this bug?”
“Yessir. We stopped along the southern coast… of Florida, near Miami, to look for survivors. Captain Brindle wanted to find a land line… or see if a radio station could be put back on the air… just in case your warning was bogus. The shore party never got that far. Survivors swarmed out of nowhere, wanting help. The shore party had to come back aboard… there were so many. That’s when the bug must have got aboard, sir.”
Captain Carl glanced at Anne while the ensign was talking. “Anything you want to know?” he mouthed. Anne mouthed back, “Anything he knows about it.”
“Well done, son. Can you tell us anything else about the bug?”
“I’m sorry, sir. The ship’s doctor didn’t have time… to do much… it hits so fast. He thought it was a bioweapon… something cooked up in a lab… to attack the nerves… in the upper spine. Too good at its job to be a mutation. Probably.”
“Understood. Is there anything I can do for you?”
There was a long pause, then, “Sir? How many of us are left?”
“There are five of us on the Moon. Since the orbital weaponry doesn’t seem to be targeting us, we’re assuming that it’s only programmed to shoot at Earth. We may find more survivors at LaGrange points four and five and in the other space stations, but we haven’t got the fuel to go exploring. We haven’t heard anything from them—at least, not yet. But thanks to your warning, we won’t be landing on Earth again; you’ve kept the bug from getting off-planet, son. Well done.”
There was a longer pause, and I wondered if he’d died on us.
Then a gasping, “Yes, Sir. Thank you, sir.”
Julie turned down the gain as the impact time approached. The cloud cover was lit from beneath for a moment, and then rippled as a flaming bubble rose through it. The radio squealed, tapering off into static.
Captain Carl drummed fingers on the console ledge in front of him. He was quiet for a long time. Finally, he turned to Kathy. “Have you got a plot on the satellite track for me?”
“Yes, Sir.”
“Good. Get the telescope on it. I want a look at the thing.” He turned to me like a turret rotating. “Max, build me a gun. A big one. We’re going to shoot that son of a bitch down.”
Captain Carl was a Navy man from before he was born. His father retired as an Admiral, his grandfather had capta
ined an aircraft carrier, and so on, back for four generations. You can say what you like about the Army or the Air Force. Disrespect the Marines at your peril; he has a fondness for them. But don’t breathe wrong about his Navy unless you enjoy being chained to an oar.
I think I’ve finally seen him upset.
* * *
Designing a gun isn’t that hard in gross; in detail, it can be hideously difficult.
The principle of any weapon is to communicate energy into the target—generally speaking, this means giving it more energy than it can handle. A laser is an obvious example; it sends large amounts of energy into the structure of a target, hopefully melting or igniting it. A projectile cannon does the same thing; the energy of the propellant is converted into kinetic energy in a projectile. That kinetic energy is transferred to the target, usually by catastrophic contact.
I can build laser-grade mirrors, but we don’t have the chemicals handy for a space laser, unless I want to experiment with a free-electron laser—but I’m not a laser expert. I can build a cannon, but, again, we don’t have the chemicals to spare for propellant. Organic compounds of any sort—anything involving nitrogen, in fact—has to be brought up from Earth. What we have is all we have.
So how do you shoot down a satellite?
Magnets!
No, I’m not talking about sucking it down out of the sky, or even an electromagnetic pulse generator. I’m talking about an electromagnetic accelerator.
It’s a series of electromagnets, each shaped like a ring. A projectile is placed on a nonmagnetic rail that runs through the rings. The first ring fires—it gets a hard jolt of electricity to make it a powerful magnet. This draws the projectile forward toward the ring. Just before it reaches the center of the ring, the power dies in that one and comes on in the next ring, drawing the projectile further down the rail, accelerating it even more.
Use enough power and enough rings and you can get things up to nearly the speed of light. We used to do it all the time in supercolliders, although not with projectiles much larger than a proton. On the other hand, we wouldn’t need to get anything going quite that fast—just a couple dozen kilometers per second. Peanuts compared to lightspeed.
So I started building rings. I fired up the robots used in constructing the base and started going over their programming. They’re extremely dumb as computers go, but they had lots of experience in construction. I started them on laying foundation and building supports for the project.
The refining machines were being pushed a bit, though. The Moon has lots of aluminum and silicates for construction or we would never have built a base. There’s actually more iron than aluminum, but processing the iron is a lot more demanding on the equipment—the process of refining iron is very different from the process of extracting aluminum. During construction, we didn’t even bother with iron, aside from a little here and there for instrumentation magnets. After all, it can rust in an oxygen environment, and that’s a major minus for a space habitat. But, with a magnetic linear accelerator to build, we were going to need all the iron we could get. Iron would be required for the magnetic cores and for projectiles.
Julie worked on that. Chemistry was more her field, after all. The refinery robots produced everything in ingots, to keep life simple—except they started re-processing what we once regarded as waste and added iron ingots to the pile. It was slow, but they worked around the clock.
Kathy supervised the rest of the robots. They were dumb, yes, but also learning machines, deliberately designed that way for construction. They didn’t take a lot of attention, but it was good to have someone watching them. They never make a mistake twice, but it’s the first mistake you have to watch for and correct.
Anne was in the machine shop, pouring molten iron into magnet molds. It’s a fairly simple job and she caught on to the tricks quickly. In one-sixth gee, even Anne could handle heavy work, and we didn’t want to have to figure out how to train a robot from scratch. Instead, we recorded her actions and would feed the data into a motion compiler later.
I was drawing. The rings needed to be placed at exact distances, mounted to withstand serious lateral thrusts—I even had to calculate the optimum size of the rings, based on the size of the projectile. There’s as much or more math in being a mechanical engineer than there is in being a pilot—just different math.
Captain Carl plotted orbital tracks to nail down the precise path of our target. He’s also been spending a lot of time at the telescope, getting a good look at it. Once you know where to look, it’s fairly easy to see. It was parked in a geosynchronous orbit, almost directly over southern California. Knowing where to look was the trick; it’s an awfully big sky.
I was in the middle of a coffee break when the Captain hailed me over the one-em-cee to come to the control room. I slid up there and found him deep in discussion with Kathy.
“What’s up?” I asked.
“The radio telescope is giving us static,” he answered. “I have it aimed at our target satellite, but I don’t get any signal, just the occasional buzz or hum.”
Kathy nodded. “I’ve been listening to it and I’ve run diagnostics, but I can’t find the problem. It may be a mechanical glitch outside.”
At least the Sun was down far enough to let the observatory wall keep me in shade. Mostly. But I missed Gary something awful right then; radio astronomy was almost entirely his pidgin. Heck, all the sophisticated electronics were his bag. We were limping along as best we could.
I missed him even more after an hour of testing. I couldn’t find a thing wrong with it. Every motor worked perfectly, every gear turned smoothly, every wire and coupler was intact and solid, not even a nick or scratch that I could find—it was enough to make a man swear. And I did, over an open mike. Kathy chided me for it.
Kathy and I scratched our heads over it for hours, trying everything we could think of, no matter how offbeat or unlikely it seemed. We couldn’t find anything wrong. But all we got was the hum and buzz. I managed to avoid swearing again only because Kathy did it for me, and quite well, too.
Finally, Kathy swung the telescope off target and aimed for Saturn. There’s an orbiter there from one of the Titan missions, watching the weather on that moon. As it should, the radio telescope worked perfectly. We heard the thing broadcasting pictures of Titan and its clouds, happy as an electronic clam.
“Max?”
“Yeah?”
“We’re idiots.”
I thought about that for a second. “Maybe. Why?”
“That’s a covert satellite, designed to avoid notice,” she said, tapping the screen with one finger. “Of course it doesn’t give off a signal. What do you want to bet the hum we hear is the computer circuitry? And the buzz is the occasional thrust of an ion engine for orbital corrections and station-keeping?”
I nodded. “Could be. Aim for another satellite and see if we can get anything from it.”
She swung the dishes around and focused on satellite after satellite, all silent.
“Our orbital weapons platform was either on a timer, or it’s specially hardened to EMP,” I suggested. “Maybe there’s a deadman component; when an EMP fries the maintenance circuit, it automatically arms the rest of the bird?”
“Possibly. Does it matter?” she asked, still checking satellites.
“Not really. We’re still going to blow it into confetti and watch it burn up on re—”
“Hush!” she said, holding up a hand. She grabbed the headphones and put them on, listening intently. I shut up and watched her move a thumbwheel with all the delicacy in her pilot’s hands. For close to two minutes, she remained tense, eyes closed, unmoving save for micrometric adjustments of the radio telescope.
When she opened her eyes, she reached for the speaker switch. Pulses of static came from the console. Regular pulses. Three short, three long, three short… pause… three short, three long, three short…
* * *
We gave our report once everyone was assemb
led in the control room.
“If they can broadcast a signal, why didn’t we hear it sooner?” was Captain Carl’s first question.
“I think,” Kathy said, “that we wouldn’t be able to hear it with normal radio reception. But our radio telescope is sensitive enough to pick up very faint signals from light-years away.” She cleared her throat. “We would have heard them sooner if I’d been thinking about your assignment, sir. How would I send a signal if I were stuck in a busted habitat? I’d set up a spark-gap transmitter. That’s as simple as two contacts a fixed distance apart so when current was applied, they make an electrical arc. Of course, the signal is weak, and it tends to be swamped by the radioactives—they both sound like static—but it seems so… so obvious, now. And then there’s the issue of my stupidity.”
Captain Carl looked startled. “I beg your pardon?”
“It didn’t occur to me that the radio telescope is a radio antenna. One that’s more sensitive to signals than anything in our communications array. But since it’s a telescope, not an antenna—at least, in my mind—it never occurred to me to try and listen to any of the habitats.” Kathy looked glum. “I’m so sorry, sir.”
“You’re forgiven. Have you been able to raise them?”
“No, sir. That also fits in with a spark-gap transmitter. They may not have a working radio.”
Julie asked, “Who is it? Can you tell?”
“Sure.” Kathy touched a key and the monitor shifted from a static-signal display to a telescopic image of a satellite. “Tchekalinsky Station. According to the computer, it has a complement of fourteen. One doctor, two meteorologists, three astronomers, five chemists, along with two cosmonauts as a full-time crew. It was one of the orbital stop-off points for material on its way here during the construction phase of the base.”
“Are there any other radio sources?” Captain Carl asked.
“We’ve only found the one, and that by accident. I’m thinking about a program to let the computer search every habitat in orbit, but we’ll need someone to listen for signals.”