The getaway special (5 page)

Judy dreaded the investigations she would have to endure once—if—they landed. Maybe it was just Carl's pessimism getting to her, but she was beginning to regret her rash defiance of authority, if only for the inconvenience it would cause her before she could actually use Allen's device for exploring. But the alternative—letting it become a military secret—felt infinitely worse. She took a deep breath and said, "Go ahead and do what you have to do."
5

As Allen keyed in coordinates, he said, "I'm going to set it for one-tenth of a percent of our first jump. That should cut our distance down to a few light-seconds, and put less strain on the engine." Judy nodded. "Good."

He pressed the "Go" button. The radio beeped, but the view out the windows remained the same. Judy didn't know whether that was because they hadn't gone anywhere, or because they just hadn't gone far enough to change the scenery. Without planets close by, that would take a long jump. They would have to leap clear across the Solar System before the stars would even start to shift position. Seconds crawled by while they waited for the radio pulse to catch up with them. Judy said, "Are you sure your receiver is—" but then the radio beeped again and Allen said, "Aha, got it! We went . . . three and a half million miles. Holy cow."

He keyed in more coordinates, then took them through hyperspace again. After five or six seconds, the radio beeped again, then about ten seconds later it beeped again. "Okay," he said, "we've got our triangulation, and that at least looks good. No aiming error. But that distance . . ." He trailed off, keying in more coordinates.

He took them on three more jumps in rapid succession. Every time Judy heard the beep of the radio beacon, she felt a shiver run up her spine. It wasn't the sound, but the momentary disorientation of the jump that went with it. Each time it happened, she imagined herself being torn apart atom-by-atom and squirted through some higher dimension to someplace else. Allen had sworn it didn't work that way, but her subconscious mind evidently didn't believe him. She wished he would at least get the thing calibrated so she wouldn't keep wondering if the next jump would take them halfway across the galaxy. But after their fifth jump in as many minutes, he was still frowning and scratching his head. "What's wrong?" she asked him.

"It doesn't make sense," he said. "It's taking far less energy to create the space warp than I calculated it would. It's almost an order of magnitude off, except for the jumps from Earth and the Moon. Those were only four or five times as efficient as I expected. But that still translates into distances anywhere from ten to a hundred times as far as I intended to take us."

"You mean you can't predict where you're going to go?"

He smiled reassuringly. "Sure I can. It's repeatable; we demonstrated that earlier. I can figure out the energy/distance correlation by trial and error if I have to, but I'd much rather be able to calculate it ahead of time, especially for long jumps. When we start going light-years at a stretch, we don't want to wind up in interstellar space with no idea of where we are."

Judy shivered. "You're right about that." She didn't even like not knowing where in the Solar System they were, but to be lost light-years away from home would be terrifying. Allen drifted up to the overhead windows and looked out. "Hmm. I wonder . . ."

"What?" A cooling fan turned on in the control console; Judy pulled herself closer to Allen so she could hear better.

"I wonder if mass has anything to do with it. I did all my initial tests in vacuum chambers at the bottom of Earth's gravity well; maybe it doesn't take as much energy to punch a hole in space when you're not close to a large mass."

Judy felt her breath catch in her throat. She had to swallow before she could say, "
Maybe
mass has something to do with it? You don't
know
?"

He shrugged. "How could I? This is my first chance to get away from it."

"But—didn't your theories predict anything like this?"

He smiled cheerfully. "What theories? I stumbled across the effect while I was working on the electron plasma battery. I puzzled it out enough to make the engine, but I don't have anything like an all-inclusive theory to explain it." He pushed himself back down to the keypad and typed in another set of numbers.

"What about relativity?" Judy asked.

Allen laughed. "If relativity could predict something like this, we'd have been using hyperdrive since 1925 or so. No, it's a completely new phenomenon." He pulsed the engine again, and while they waited for the timing signal to catch up he said, "I'm betting it won't contradict anything we already know, but we'll probably have to modify our existing theories to account for it. In the meantime, if we can figure out how it works experimentally, we'll be miles ahead of the theorists."

"So to speak," Judy said.

The radio beeped, and Allen said, "Okay, another three million miles. Now we go back near a gravity field . . ." He punched in more coordinates, and when he pressed the "Go" button Earth blinked into view again, this time at least half a million miles away. The Moon was just a small sphere beside it. Allen didn't wait for the timing pulse to catch up. He set up another jump, and this time Earth shifted across the star field. They'd apparently gone sideways, rather than toward or away from it. When the timing pulse from that jump arrived, Allen nodded and said, "Two hundred thousand. Much shorter. So gravity
does
affect it. Now we just have to figure out how much." He began to whistle softly as he set to work analyzing the data.

After a few minutes, he said, "Hang on; I'm going to see if I can actually hit a target this time."

"What target?" Judy asked immediately, but he'd already pushed the button. She looked out the windows and gasped in surprise. Saturn had swelled into view like a soap bubble rising from a cosmic bathtub toy. The planet itself looked about the size of the full Moon seen from Earth, with its rings more than double that width. The shuttle had materialized over one of the poles, so the rings went all the way around.

"Very funny," Judy said.

Allen looked out the window and grinned. "Good old inverse-square law. You've got to love it." Anybody who knew how to calculate an orbit knew the inverse-square law: the gravitational attraction of a given mass dropped off with the square of the distance from it. The same rule worked for light intensity, sound volume, and just about any other quantity that issued from a point source. Judy tried to imagine how it applied here. It was hard to think with Saturn just outside the window, but she forced herself to look away and concentrate on what Allen had said. "So did jumping to Saturn just now take more energy than the same distance in flat space, or did it take less because we were going downhill?" Allen shook his head. "More. Apparently whenever you get near mass, it takes more energy to create the warp field, no matter which way you go. You've got to warp it twice, see, once at the point where you leave the normal universe and once where you drop back in." He wrinkled his forehead, thinking, then said, "In fact, if it took less energy going toward a big mass, then we'd probably have wound up inside a black hole on our first jump."

Judy winced at the thought, but Allen didn't notice. He said, "The good news is, distance is just a minor factor in the equation, so as long as we don't try jumping directly from planet to planet, we can make interstellar jumps without having to take along a nuclear reactor for power."

"I thought you said you could jump directly from the surface into space."

"You can. You just don't want to go very far on the first jump, or it uses more energy. So you make a short jump to get outside the gravity well, then a long jump to someplace near where you want to go, then another short jump to land.

Well, actually a bunch of short jumps, because you can't go all the way to the surface."

"Why not?"

Allen had been waving his arms as he talked; he reached out to one of the remote video monitors to steady himself. "Two reasons. When you jump, you keep your initial velocity, so unless you match it perfectly with the spot on the ground you're trying to land on, you'll be moving when you get there. But the other reason is that you can't appear where there's already something in the way. Even air is too thick. So you have to appear outside the atmosphere and fall the rest of the way in with a parachute."

"Or fly in," Judy said. She looked out at the stump of the vertical stabilizer.
Discovery
wouldn't be flying anywhere for a while.

She shuddered to think what would have happened if the A-sat weapon had hit the crew module instead of the tail. Or if they'd been just a few more minutes in repairing the hyperdrive, or if the space warp it generated hadn't been big enough to take the whole shuttle along with it. They were lucky to be alive.

Saturn lured her attention again. Part of her, the little girl who'd dreamed of space travel, boggled at the sight, but the part of her who captained the space shuttle was thinking,
He didn't even know how it
worked before he yanked us out of orbit
.

Maybe knowing how many things could go wrong on a space flight made her paranoid, but the knowledge that Allen was flying by the seat of his pants didn't inspire confidence. What if he'd missed something else equally obvious? In fact... "Wait a second. Are we outside Saturn's radiation belts?"

"Radiation belts don't extend over the poles," he said.

"You're sure?"

He nodded. "Relax. I know what I'm doing. And now that I know how to correct for mass, I can put us back in Earth orbit any time we want."

Provided the hyperdrive didn't burn out again. Judy imagined them falling into Saturn if it failed. Or would they starve first? How far away were they, anyway, and how strong was Saturn's gravity at this distance? And even if they didn't fall into Saturn, what about the unwanted velocity they'd picked up from their time near the Moon? Aloud, she said, "You don't have any idea what our actual vector is, do you?

Like you said, we could pop into the right place, but doing seventeen thousand miles an hour straight at the ground. Even if we start out a couple hundred miles up, that doesn't give us much time to react." Allen looked out over Judy's shoulder. He didn't say anything for at least a minute, and when he did speak it was only to say, "We're farther out than anyone has ever been. Seeing something nobody else has ever seen. Doesn't that mean anything to you?"

The rings looked like tie-dyed silk. Specks of brightness just beyond them had to be the shepherd moons. Judy could almost hear the theme from
2001: A Space Odyssey
playing in the background. She shook her head and the music stopped. "Sure it does," she said, "but it also means if something goes wrong, we're dead. I'm just trying to keep that from happening." Carl chose that moment to float up through the hatchway, an even more worried than usual look on his face.

"What's wrong?" Judy asked.

"We've got eight days of consumables," he said, "but the toilet's broken, and Gerry's got to go. At least he says he does."

"Oh, great." The power of suggestion made Judy suddenly notice the pressure in her own bladder, too. She tried to ignore it, but she knew it wouldn't be denied for long. Nor would Gerry's. "Well, he'll just have to use a waste bag," she said. "For that matter, he'd have to use one anyway, because I'm not letting him loose again."

Carl scowled. "We can't keep him in that bunk forever."

"We're not going to. Allen is just about done here, and I think we've pushed our luck far enough for one flight. As soon as we're sure it's safe, we're going back to the space station."

"Good," Carl said. He pulled himself down into the mid-deck again without even looking out the window.

Allen did. Judy found her gaze following his, once more drawn to the spectacle of Saturn floating just outside. The planet was half in light and half in shadow, the soft texture of its cloud layers giving it the puffy three-dimensionality of an overstuffed pillow. Its rings, on the other hand, were so flat an abstraction that they looked unnatural, like a collar drawn with a felt-tip marker on a hologram of a cat.

"Sure you don't want to stop off at Mars?" Allen asked softly. She took a deep breath, then sighed and looked away. "Not this time. Let's go home."
6

"It'll take three jumps to put us back in orbit," Allen said. "I already figured out how to do it weeks ago. I call it a 'tangent vector translation maneuver.' "

"That's kind of a mouthful," Judy said. She and Carl were looking over his shoulders again as he programmed the coordinates into his computer.

"It's descriptive," Allen replied. "When you're in orbit, your vector is always tangent to the point you're occupying at the moment. So to slip into a particular orbit, you have to translate your current vector into one that's tangent to the orbit you want. What we do is jump to within a few thousand miles of Earth, where we're close enough to use the tracking satellites and ground radar to establish our vector but far enough away to keep from hitting anything if we're aimed the wrong direction. Then once we know how fast we're going and what direction we're headed, we jump to the right point over the planet for gravity to warp our trajectory into the right one for where we want to be, and then we pop into low-Earth orbit with just the right vector. It's a piece of cake."

"Famous last words," Carl said.

Allen ignored him. "First translation coming up." He pressed the "Jump" key. The radio beacon beeped. Judy looked out the forward windows just in time to see Saturn vanish like a switched-out light, and Earth pop into existence to the right of where it had been. It was much larger, filling about sixty degrees of view, which meant they were closer than the Moon, but still way beyond normal orbital altitude.

"Checking our position . . ." Allen said slowly. "Hah! I was less than fifty kilometers off target."

"Good for you," Carl said in a voice that said just the opposite. He turned away and pulled himself past Judy into the copilot's chair.

"What are you doing?" she asked when she saw him reaching for the radio controls.