"But the Intruder's moving considerably faster than that," Assembly-Prime Wu-sin objected.
"Exactly," Roth nodded. "They're apparently using an after-accelerator of some sort to boost their exhaust speed. But this takes energy, requiring extra fuel."
"I see," Nordli rumbled. "They have to carry extra hydrogen which can't be replaced in the interstellar medium. So they periodically dive into a star to replenish their tanks?"
"It would seem so."
"Dr. Du Bellay, you're an expert on alien cultures, correct?" Nordli asked.
"To some extent, sir," Du Bellay said, "bearing in mind we've so far studied only dead civilizations, and only a handful of those."
"Yes. In your opinion, what are the chances of communicating with these aliens? And what are the chances that would make any difference in their actions?"
Du Bellay frowned. "I'm afraid the answer to both questions is very poor," he said slowly. "It's true that various scientists have developed so-called 'first-contact primers' in case we ever came across a living intelligent species. But it's also true that teaching any of our language to an alien would take considerable time, and we haven't got that time. No ship ever built could match speeds with the Intruder, so we would have to give everything to them in short, high-density data bursts. And even assuming they were equipped to receive whichever wavelengths we use, they have only seven or eight hours—in their time frame—to decipher it."
"I have to concur with Dr. Du Bellay," Carey spoke up. "As a matter of fact, we've already sent out a series of tachships to try precisely what he suggested, but we don't expect anything to come of it."
"Perhaps we could signal our existence some other way," Evelyn Woodcock, Nordli's assistant, suggested. "Say, a fusion drive pointed at them, blinking off and on. They couldn't miss that."
"And then what?" Carey asked.
"Why—surely they'd change course."
"With their own mission at stake? If it's a colony ship of some kind, its supplies are likely very tightly figured. If they change course, they may die. At the speed they're making we sure as hell can't offer to refuel them."
"There's an even more disturbing possibility," Nordli said quietly. "This refueling technique may be deliberately designed to sterilize the system for future colonization."
"I think it's unfair to ascribe motives like that to them without proof," Du Bellay said. The words, Carey judged, were more reflex than true objection—the archaeologist looked as uneasy as everyone else.
"No?" Nordli shrugged. "It doesn't really matter. What matters is that the Intruder is threatening us with massive destruction. We must stop him."
Wu-sin stirred. "Executor Nordli, you're proposing what amounts to an act of war against another intelligent species. A decision of that magnitude must be approved by the full Solar Assembly at least; ideally by all the colonies as well."
"There's no time to consult the colonies," Nordli said. "As to the Assembly... you have two hours to get their approval."
"And if I can't?"
"I'll go ahead without it."
Wu-sin nodded grimly. "I needed to know where you stand. I'll get their approval." He rose, bowed, and left the room.
Nordli turned to Carey. "General, how do we proceed?"
Carey let his eyes sweep the others' faces as he thought. They were all on Nordli's side, he saw: Du Bellay, like himself, only because there was no other choice. How many lives were they planning to snuff out?—innocent lives, perhaps, who may not realize what they were doing? "The trouble, Mr. Executor, is that the Peacekeeper forces really aren't set up for this kind of threat."
"You've got nuclear missiles, don't you? And ships to deliver them?"
"There are two problems. First, hitting the Intruder would be extremely difficult. A shot from the side would probably miss, alerting them as to our intentions. A head-on shot would hit, all right, but the extremely high magnetic fields it would have to penetrate would almost certainly incapacitate any missile we've got. And second, there's no guarantee even a direct hit would do any good. Just because they don't have FTL drives doesn't mean they're primitives—only that their technology developed along different lines. And don't forget, that ship is designed to bore through the edge of a star at nearly lightspeed."
"There's one further problem," Dr. Roth spoke up. "Disabling or even disintegrating it at this point wouldn't help us any. The fragments would still hit the sun, with the same consequences."
There was a moment of silence. "Then we have to stop or deflect it." Evelyn suggested. "We have to put something massive in its path."
Nordli looked at Carey. "General?"
Carey was doing a quick calculation in his head. "Yes, either would work. Slowing it even slightly would sent it through a less dense region of the photosphere. Assuming, of course, that he stays with his present course."
"What can we put in his path?" Nordli asked. "Could we tow an asteroid out there?"
Carey shook his head. "Impossible. As I pointed out, he's far off the ecliptic plane. Moving an asteroid there would take months." Even as he spoke he was mentally checking off possibilities. Tachships were far too small to be useful, and the only heavy Peacekeeper ships in the System were too far away from the Intruder's path. "The only chance I can see," he said slowly, "is if there's a big private or commercial ship close enough to intercept him a good distance from the sun. But we don't have authority to requisition nonmilitary spacecraft."
"You do now," Nordli said grimly. "The government also guarantees compensation."
"Thank you, sir." Carey touched an intercom button and gave Captain Mahendra the search order.
There was a lot of traffic in mankind's home system, but the Peacekeepers' duties included monitoring such activity, and it was only a few minutes before Mahendra was back on the intercom. "There's only one really good choice," he reported. "A big passenger liner, the Origami, almost a hundred thousand tons. She's between Titan and Ceres at present and has a eighty-four percent probability of making an intercept point on time; seventy-nine if she drops her passengers first. One other liner and three freighters of comparable size have probabilities of fifteen percent or lower."
"I see," Carey said through suddenly dry lips. "Thank you, Captain. Stand by."
He looked back up at Nordli. The Executor nodded. "No choice. Have that liner drop its passengers and get moving."
"Yes, sir." Turning to the intercom, Carey began to give the orders. He was vaguely surprised at the self-control in his voice.
—
"Well, Shipmaster?" Lassarr asked.
Orofan kept his expression neutral. "I have no suggestion other than the one I offered an aarn ago, Voyagemaster: that we change course and continue at reduced speed."
"For six lifetimes?" Lassarr snorted. "That's unacceptable."
"It won't be that bad." Orofan consulted his calculations. "We could penetrate the outer atmosphere of the star without causing significant damage to the system. We'd collect enough fuel that way to shorten the trip to barely two lifetimes."
"That's still not good enough. I have no wish to join the ancestors before our people are safely to their new home."
"That can be arranged," Orofan said stiffly. "You and any of the Dawnsent's crew who wished could be put in the spare sleep tanks. If necessary, I could run the ship alone."
For a moment Orofan thought Lassarr was going to take offense at his suggestion. But the Voyagemaster's expression changed and he merely shrugged. "Your offer is honorable, but impractical. The critical factor is still the durability of the sleep tanks, and that hasn't changed. However, I've come up with an alternative of my own." He paused. "We could make our new colony in this system."