by John Barnes
Virgo propels itself by heating water from the iceballs to a very high temperature in its fusion reactors, and then sending the white-hot steam out the nozzles of the engines. How much Virgo can change its course depends on how much water it can push out. With only one iceball instead of the four it needed, it cannot push nearly as much as it should.
How much change does Virgo need to make? They are 123 days, or 167 million kilometers, from Marspass. If they could do the full course correction Virgo was planning to do (about a two-degree bend in their path and speeding up by about 3300 km/hour), they would pass within 20,000 kilometers of Mars. But every thousandth of a degree, or every kilometer per hour, that they can’t correct for now will widen the closest-point gap between them and Mars by 3,000 kilometers.
How can such small things make such a big difference? If you’ve studied trigonometry, you know the difference at the far end is equal to the tangent of the angle you are off by, times the distance you are covering. The tangent of 2 degrees is about .035, and .035 × 167 million kilometers = about 5,830,000 kilometers, or 15 times the distance from the Earth to the moon; so even if they were moving fast enough, they’d cross Mars’s orbit 5.83 million kilometers behind Mars.
But they’re not going fast enough.
Mars orbits the sun at 24 kilometers per second, so if you are aiming at the place where Mars is going to be when you get there, and you are late by an hour, one hour = 3,600 seconds X 24 km/sec = you miss by 86,400 kilometers for every hour you are late.
To be on time, they would need to average about 97,200 km/hour, but they’re going 3300 km/hour too slow, which is 93,900 km/hour. Their trip time to the Mars rendezvous should be 123 days X 24 hours = 2952 hours, but at their slower speed they will take (97200/93900) X 2952 hours = 3056 hours. That’s “only” 104 hours late—a little over 4 days—but as fast as Mars is moving, it widens the gap by another 9 million kilometers.
Glisters says, “Commander, there’s something you’d better look at here—I think you, too, Susan.” He swings his chair out to reveal his screen, which shows a view of each of the six sections of the pod. “The good news,” Glisters says, “is that none of the trees fell over, and Farm Sections 2 and 3 were inactive, so everything in them was locked down in bins and beds. But there’s a lot of spilled dirt and water in Farm Section 1, and bad news in all three cargo sections.” On the screen, hundreds of little shapes—spheres, blocks, pyramids—like a kid’s building set, are scattered all over the cargo walls, bulkheads, and decks. Most are blue and arranged neatly; some are yellow, at funny angles but still in the general array; many red ones are heaped together or lying across the array. “Red means unhooked and out of place, which means ‘going to fly around and do more damage while we correct our spin.’ Yellow means the hook or attachment is saying it’s not fully secure, like a hook is open or a line is broken or something. Blue means it’s fine.”
He touches a red cube; it lights up with a string of numbers, and the same numbers appear on a cargo wall in the same hold. “That’s where it is, and that’s where it should be. In this low gravity, usually you should be able to put them back onto the hook they came from, but if it’s huge and you can’t move it safely, just hook it somewhere. Anyway, I think probably we can have it all rehooked well before the ship is back on its proper spin—”
“But why should we?” Wychee returns to her basic approach to the universe.
“Good question,” Glisters says; his eye contact with me is saying, don’t jump on her. “We want all that stuff locked down because it will make it safer for us to correct our spin, which has an ultra, ultra lot to do with our comfort, but also we need the spin fixed so we can course-correct into a trajectory that gets us close enough to Mars—”
“I want to turn around and go back.”
“Me, too, but for that we’d need about a hundred more engines and at least 400 iceballs, and we don’t have them.”
“Could we pool our allowances, get money from our families, and just buy all that? I bet my parents would chip in just to avoid the scandal—”
I wonder if she listened, back on Earth, or if she just didn’t understand what it meant. Either way, we can’t afford to have anyone thinking we’re just being mean. “Wychee,” I say, “we can’t buy anything out here. There’s no one to sell it to us, it doesn’t exist, and there’s no way to deliver it. The ship is going to pass close to Mars because it orbits that way. But if we don’t correct the course, it won’t pass close enough for a cap from Mars to rescue us. And before we can correct the course we have to straighten out our spin, back to what it should be, because—hunh. Glisters, why can’t we just fly like this?”
“We could if we had enough spare reaction mass, Susan. With the ship tumbling, we’d need to fire off a lot more steam through the nozzles to get the same effect as we’ll get with the ship corrected. It’ll cost us some water to correct the ship, but not nearly as much as we’d lose by trying to fly while tumbling.”
“And we’re going to be on the ship for months, even if they launch a rescue mission tomorrow,” Emerald adds. “It takes that long to reach us. So it would be nice to have up and down be where they’re supposed to.”
Wychee doesn’t say anything, but she looks furious. I ask, “Does that make sense?”
“I don’t like it.”
“But do you understand it, and does it make sense?”
“Yeah,” she says. “Yeah. I’m just now realizing how much this is like the time my stupid tutor ran out of fuel in the middle of the Pacific, on the field trip, and it didn’t matter how many eenie kids with how many credit accounts were on board, we had to wait for the fuel to come from Hawaii. And this is, like, ultra bigger, right?”
“Ultra-ultra,” Glisters says. “Remember the Columbus-and-the-Atlantic example from school? Same deal.”
He’s talking about a math problem everyone does sometime in grade school. You divide the total volume of Columbus’s ships by the total volume of the North Atlantic and come up with about two quadrillionths; then you divide the total volume of all the spaceships patrolling or carrying cargo between Earth and Mars by the volume of the doughnut-shaped space that the Earth’s orbit and Mars’s orbit mark out around the sun, and get about one septillionth. You divide that out and you find out that the Atlantic, proportionately, contained a billion times more of Columbus’s ships than Earth-Mars space contains spaceships, even today, when there are more than 50 regular cap launches and recoveries on Earth per day.
Wychee says, “I suppose I’m mad because they told me space was big and empty since I was little, but I feel like they never told me how big and how empty—there was that business about traveling thirty times as fast as a rifle bullet and taking four months to get to Mars, and that didn’t really sink in, either, till just now. So we’re all alone out here.”
“And it’s ultra not fair,” Derlock says, “and I don’t think we should have to—”
“Shut up,” Stack says quietly. “Uh, if I’m allowed to tell him to shut up, Commander.”
“I’m authorizing it immediately,” Emerald says, “and thanks for your initiative.”
Stack says, “Glisters, if I get it right, the deal is this: We can’t get close enough to Mars without course correction. We can’t do course correction while we’re tumbling. We can’t stop our tumbling—at least not safely—until the stuff is tacked down. Does that cover it?”
“Uh, brilliantly,” Glisters says.
“Then let’s tack the stuff down. We can figure the rest out later. I want to understand it, but I want to do what we have to get done first.”
The short silence is broken by Emerald saying, “He’s right. Show us what we need to do, Glisters.”
He puts it up on the big screen. “Well, the red ones are unattached objects, which will fly around and could break things or hurt people, and the yellow stuff is loose objects that might come loose and turn into red stuff. So in between each burst from the thrusters, we need t
o go out and drag the red ones back into place and hook them down, and then re-fasten the hooks on the yellow ones. We’ve got seven more thruster bursts coming, the next one in—about forty minutes.”
Stack nods. “Okay, I see that part. Why do we have to wait so long between firing thrusters and engines? Why not just fire them all at once and get this thing right-side-up right away?” Under his natural deep brown skin he’s distinctly turning gray-green; maybe the swaying cockpit is making him motion sick.
Glisters says, “It’s another problem with being on a broken ship. We’d do it that way if we had the whole ship to work with. But out of eight engines we should have, we’ve got two working. So the computer has to wait till it has a working thruster or engine in the right position to give us just the right size push in just the right direction. Then once it corrects it has to wait for another thruster to come into place, and so on. Actually it’s more complicated than that because I asked it to figure out what would waste the least water, since we want to have as much as possible to do our course correction. As it is, we’ll use up almost all the remaining ice just to put ourselves barely in range for caps coming up from Mars.”
“But they will come and get us, won’t they?” Fleeta asks. “They won’t be mad at us, and just decide not to bother?”
“They might be mad, but they’ll still come and get us,” Glisters says. “What worries me is that I keep getting MESSAGE NOT SENT when I try to send out the distress call, either the automatic or the custom. And I think that’s because the antenna on the nose spire is gone—the nose would have whipped around harder than anywhere else, the sensors aren’t showing it’s there, and I think the force just tore it off—and the one on the tail was dead, and in for repairs, at the time we were hit. It’s apparently waiting in the tail airlock for installation—”
“Well, then, let’s install it!” Stack says.
“Hold on. That means going outside in an evasuit and working on the extreme tail of the ship, and right now, while it’s tumbling, whoever does it could fall away into space—and we don’t have any way to rescue them if they do, the second they lose grip on ship, they’re gone for good—or much worse, the antenna could accidentally fall away and be lost.”
“Losing the antenna is worse than falling away and dying in space?” I ask.
“There’s nine of us and only one antenna,” he points out. “So there is an order we have to do things. First hook the cargo. Then straighten the spin. Those can overlap a little. As soon as we’re done with that, fire the course correction, because the sooner we do it the more effective it will be. Next, with the ship spinning in its regular way, and after we practice and get it all figured out right because we only get one chance, we put the antenna out there and let them know we’re on our way to Mars. No matter what, it will be four months before our closest approach, so they’ll have time enough to prepare, even if we don’t call in for a month. But to make it possible for them to rescue us at all, we need to do the course correction as soon as possible.”
Emerald nods. “Everyone understand why we’re doing this? Good. Wait—where’s Marioschke?”
Wychee says, “The last I saw of her, she was sitting on her sleepsack in lotus with her hands wrapped in handholds so tight the knuckles were white, eyes tight shut, and om-ing like crazy. I think she was trying to pray herself out of this. I tried to get her to come along, Em, I did, but the others were leaving and—”
Emerald says, “Oh, I believe you. Whoever sees her next can try again. She might cooperate more once she’s hungry or needs to pee. Meanwhile, though, she’s not hurt?”
“Not unless ‘scared out of her mind’ counts as hurt.”
“If that counts, we’re all totally disabled. All right, here’s how we do it. Glisters, do our phones work locally?”
He clicks keys for a moment. “They do now.”
“Good job,” Emerald says. “Let’s try one thing first.” She tells her phone, “Marioschke.”
Marioschke picks up, shouting, “Help, the ship is broken and I don’t know what to do!”
“This is Emerald—”
“Emerald is dead, everybody’s dead, the ship is broken, my dad will pay you whatever you want but come and get me!”
“Marioschke, we’re—”
“Come and get me! The ship is broken!”
Emerald sighs and breaks the connection. “We don’t have time for this right now, and she can’t be any more upset than she is already, can she? All right, then, Glisters will stay here and text out to the crews, directing us to whatever needs to be fixed.”
He says, “Set your phone to pop me up on voice—loud! If stuff is moving around I may need to tell you right then, and I want you to have enough time to grab a handhold before each thruster burst.”
“What Glisters said,” Emerald says. “Glisters, do we have pressure suits?”
“We must, but I’ll have to locate them.”
“Then we’ll start in the Pressurized Cargo Section first. I’m going to put you into teams—”
“What makes you think I’m going to follow your orders?” Derlock says.
“Because you’re going to be my teammate,” I tell him, “and if you either fuck off or fuck up, I will lop off your worthless dangly little pink nadsies and make you eat them,” trying to style like Pop in Space Patrol to Saturn!, but to judge by the way people are reacting, I’m styling more as insane psychobitch ex-girlfriend. Good. That probably scares him more anyway. “We have things to discuss while you are being a big useful collection of muscles, anyway.”
“Thanks for volunteering,” Em says, smiling at both of us.
“How about me, F.B., and Fleeta as a team?” Wychee says.
Emerald nods. “Good. Stack, you’re with me.”
Interesting, I think. Each group has at least one person from Em’s core group and one from Derlock’s late arrivals. Em and I have the two potential mutineers. And Wychee helped make it look spontaneous. I hope Wychee wasn’t just useful by accident.
At the coretube we grab the recessed handholds and climb; it’s 5 meters across, so there’s plenty of room for all of us to climb side by side. As we go up the gravity decreases, up to the weightless spot at the center of mass, where I do a handstand, which is easy in the low gravity, and get my feet pointed the other way for the climb down into the nose end of the pod. All the others copy me, although F.B. has to try it twice before he figures it out.
As we climb down the gravity increases. Glisters speaks over all our phones. “All right, at Cargo Wall 44, Wychee’s team peel off, and I’ll text you your instructions.”
Wychee opens a hatch into the space between the cargo walls and helps Fleeta and F.B. through it; we watch this above us as we keep climbing down. Glisters is sending Stack and Em all the way to the nose end, because they’re the most muscular team, collectively, and that’s where gravity will be highest and unhooked cargo most abundant. Derlock and I peel off at Cargo Wall 14, to work our way down and meet Em and Stack.
Derlock says, “See, that’s not fair, Glisters gave the first team thirty cargo walls to cover, he gave us thirteen, and those guys are only doing Cargo Wall 1.”
“He’s looking at the amount of work, not the number of cargo walls. The farther out toward the nose, the bigger the change in gravity, and the more cargo shook loose. Besides, anything that went over the edge of any cargo wall between 1 and 49 fell noseward. Glisters worked it out so that we all have the same amount of cargo to shift.”
Halfway down Cargo Wall 14, three tumbling containers have loosened two more. We reconnect the cargo hooks on the two that are showing yellow on Glisters’s screen, then look over the situation on this wall—this floor, for the moment. A three-meter cube painted bright red has slid about ten meters hullward; it is leaning against a mud brown box, a meter and a half on a side and five and a half meters long. A dull yellow cylinder, half a meter across and a meter long, lies wedged hard between the other side of the red cube and t
he cargo wall.
“My executive decision as pilot and team leader,” I say, “is that we try to move the little yellow one first, then the long thin leaner, and then the big red one.”
“Yes, sir, Mister Pilot Sir!” He gives me a lame parody of a salute.
I give him the raspberry. “Come on.”
There are cracks in the red cube where the yellow cylinder jammed into it. We push on the red cube and it lurches wildly; we jump back, and the cylinder rolls out from under it and heads hullward with a low, heavy rumble.
We bound after it; it slams into an anchored black crate and gets stuck there.
Lifting the cylinder, or even getting a hand under it, is impossible. We shove it hard to free it from the cube, and let the cube settle back with a thud.
We can’t lift the cylinder, even in the low gravity, but it’s easy enough to roll it to the place it fell from. After we rehook it, I ask Glisters, on voice, “How can anything be that heavy in such low gravity?”
“It was a solid-gold copy of a Louis Quinze ottoman encased in concrete to prevent dents. They do that for things like that; at the other end they just have nanos eat the concrete. So you made sure it’s dogged down good? I don’t want that smashing against a window, no matter how tough that window is supposed to be.”
“It’s back on its hook and the hook says it’s fine, but who knows? It got loose before; is there going to be another lurch that big?”
“Not if I have anything to do with it.”
“Then we’ll be fine. What’s in the other boxes?”
“The long brown box is handmade quilts and rugs,” Glisters says. “The red cube is orange tree seedlings on a centrifuge—that’s why it jumped like that.”
“Why are they centrifuging the trees? Are they trying to pre-extract the juice or something?”
“They don’t have suspended animation protocols for trees, so they put them into a centrifuge with a light at the center, to keep them growing straight on their way to Mars.”