Xmary thought that one over. “Okay. Okay, something like that, surely. What do we do about it?”
“Good question,” Feck said.
On Conrad's board, the damage alarms lit up again, more insistently this time. This time the broken threads were on the capward edge of the sail, which was still filling out to its full expanse. The spot was smaller—only fifty meters across now—and it wandered fitfully around a square kilometer of sail, but did not leave it.
“The spalling laser is back,” he reported. “They're having trouble keeping it focused, but it's definitely a threat to the sail. Not so much the hull.”
Xmary sighed. “The sail is a one-way mirror, right? Clear on the forward face and superreflective on the aft? Go superreflective on the fore as well.”
“That'll reduce our photon thrust,” Conrad warned.
“Until we pass out of Barnard, yes,” she agreed. “Once the star is behind us, it won't matter.”
“This is where the sail does us the most good,” he pressed. “You're cutting into our net impulse, prolonging the journey.”
“Understood,” she snapped. “But let's get there alive, shall we? Feck, I want you to start a juking program as well. Full lateral thrust at a ten-percent duty cycle. And yes, that's going to waste fuel, making the journey longer still. Do it anyway.”
“Aye, ma'am.”
She fretted for several seconds, while Bascal's image launched back into its “Fuck You Song.” Finally, over the racket, she said, “We can't stay on the defensive like this. We've got to shake them up. Conrad, what kind of beam can you throw their way?”
Conrad spread his hands. “I can generate a laser, ma'am, but they're stealthed, and probably juking as well. And they're a much smaller target than we are. All I can do is aim at my best guess.”
“Without ertial shielding they're limited by fuel,” Xmary said, “and they haven't got nearly the thrust that we do. If they're juking, it's minor. And we have the whole sail to use as a beam generator. Wasting power, yes, but a laser beam ten kilometers wide ought to be rather difficult to avoid. Feck, are you up for that?”
“No, sorry. Ma'am, if we're willing to sacrifice half our thrust, I can deliver you two gigawatts. Unfortunately, spread out over a hundred square kilometers of sail, that's about the power of a desk lamp. They're already fighting off Barnard's heat at sixteen megawatts per square meter, so we want to be at least as big a problem as that. Meaning the beam needs to be, uh, less than eleven meters across.”
“I can't hit them with that,” Conrad warned. “Not bloody likely. I can't see them. They're two seconds lagged, now, but I can't even see where they were then. They're invisible.”
“Shit,” Xmary said, throwing up her hands. And then a tentative expression broke out across her frowning face. “Wait a minute. Feck, they're absorbing all this heat from Barnard, right? And they're dumping it in the opposite direction. Every watt, or they'd be slowly cooking in there.”
“We're doing the same,” Feck said. “Blackbody emissions on the shadowed upward face. The radiator flux is called huela puho, a blaze beam.”
“Yeah, but we're not invisible and they are. Unless they're immediately upsystem from us, we should see a hot spot. Maybe they're hiding the emissions in a narrow frequency, longwave radio or something, but one way or another, all that energy has to go somewhere.”
“I've been scanning for a hot spot,” Conrad complained. “I can't find one, in any frequency. My guess is, they're focusing it in a blaze beam directed away from us.”
“Yes,” she said, lighting up in angry triumph. “And that's how we get them! We just need to redirect all this heat from the sun. The beam of our own waste heat, eh? We reflect it right onto them, as bright as the sun itself. Two suns at once! We don't need to be precise about it, just wave it in their general direction. They can't do the same to us—they don't have enough collection area. But with all this energy hitting both sides of our sail, we can overwhelm their cooling systems. They're probably running at full capacity already.”
“They probably are,” Feck agreed.
And with growing enthusiasm Conrad added, “Even impervium breaks down at thirty megawatts per square meter, ma'am. A fraction of a fraction of that energy slips in between the pseudoatoms, and the heat kicks the electrons right out of their quantum wells. The whole thing reverts to silicon fibers and then vaporizes. It's why you never hear about probes to the center of the sun. Nothing could survive that trip, because there's nowhere to dump the heat.”
“Hooray!” Eustace called out. “We'll get those bastards!”
“Not so fast,” Conrad warned. “We don't want to overwhelm our own systems while we're at it. We'll blow ourselves up if we do. Also, we really do need the push this light is giving us, or we'll be sailing in the dark for a thousand years. Let me check some numbers on this.”
“Do it quickly,” Xmary said, leaning over toward his station. “If I read your displays correctly, the sails won't be holding together much longer.”
This objection was entirely valid. Indeed, despite the side-to-side juking—which really was throwing the ship around in a way the ertial shields couldn't mask—Fist's spalling laser was doing a better and better job of focusing on a smaller and smaller area. In another minute or two, the thread damage would reach critical levels, and the wellstone sheeting, far thinner than a human hair, would start to unravel and lose its charge. And without the exotic electron bundles that held it together—the pseudoatoms which resembled natural atoms in the same way that starships resembled sparrows—the material would quickly disintegrate under the heat and pressure of Barnard's light.
However, this was not a calculation Conrad had ever performed before, or even imagined he might someday need. How much energy could you put through a properly programmed wellstone matrix, and for how long?
“Hurry, please,” she pressed.
Bascal, meanwhile, sang, “Fuck you, and fuck you, and fuck you, and then / Fuck you and fuck you and fuck you again. / Fuck you and fuck you and fuck you my friend, / For fucking with me you'll be fucked till the end!” It was an old song, maybe older than the Queendom itself, and this was just the chorus. The stanzas went on and on and on. And on.
Even with hypercomputers at his disposal, Conrad had never been all that brilliant with numbers. He was still less so on the noisy bridge of a heaving starship under full thrust, and under attack by unseen enemies. Still, eventually he got an answer, padded it for safety, and fed it down to Feck for confirmation. “Ma'am, we can illuminate the target for a hundred millisecond window out of every second. That's a safe number that will keep us alive, but if our aim is good, it should pop their cork in less than a minute.”
“All right,” she said. “Do it. Ten-percent duty cycle.”
And although Conrad was a damned talented programmer, easily better than King Bascal himself, this was another challenge which took more than a moment to address. More than two moments. More than six. By the time he was finished, by the time the ship was rocking and stuttering under the intermittent thrust of its newly weaponized sails, the sails themselves had begun to sprout man-sized holes. Damn that spalling laser! On the plus side, though, the invisible antimatter bombs Feck had predicted were flashing into oblivion in the distance, succumbing one by one to the scorching beam of concentrated sunlight.