Man-Kzin Wars IV by Larry Niven (graded readers .txt) 📗

he liked to jab into his holos—and sometimes into the bellies of his less attentive listeners.

“We do not know its intention,” the ghost-memory was saying to Trainer. “It is probably coming to sniff spoor around our boundaries. It cannot have an attack capability.”

Trainer tried to reevaluate was that still true?—and drew a blank.

“It cannot defend itself.”

Yes, thought Trainer, its speed is its only defense, running like a fangless herbivore.

“The most interesting fact that this mockup reveals about the United Nations Space Navy is that they have not—as of four years ago, I repeat—learned how to build an interstellar-grade gravity polarizer. Otherwise they would not be launching such a massive low-performance device. The magnetic funnel”—he pointed—“is used to collect interstellar hydrogen for the reaction drive. Can any of you tell me its major constraint?”

There had been silence in the classroom. Today it was the silence of interception through soundless space.

Trainer remembered himself prompting, mischievously, “Ask Long-Tooth. He knows.”

Long-Tooth-Son of Grraf-Hromfi jumped out of his reverie. “Honored patriarch, a ramscoop is too slow.”

“Its acceleration is too feeble,” corrected the father. “And why is that?”

Long-Tooth cast Trainer a venomous look for getting him into this dialog. “There’s not much hydrogen for it to use.”

“How much?”

“Sire! I don’t know.”

“Trainer-of-Slaves?”

“Please accept my surrender if I am wrong. Between here and Man-sun the density is about an octal-squared to four-octal-squared hydrogens per fistful of space.”

Grraf-Hromfi again passed the slashtooth tusk of his pointer through the fuzzy holographic ramscoop in front of him. The spout of its funnel was burdened by racks of spherical tanks. “They need these huge hydrogen tanks to prime their reaction engines since they can’t collect much hydrogen at low speeds. The tanks will be dropped off once they are moving fast enough to devour more than starvation rations of the interstellar hydrogen.”

He was grinning at monkey folly. “They can’t collect much at high speeds either in spite of the fact that the main funnel collector surface seems to be about as large as the Patriarch’s private hunting estate. Their maximum speed is a quarter that of light if they use a ramjet design. With a more sophisticated flow-through design they are only limited by relativistic effects which are considerable. I doubt a top velocity beyond a half-lightspeed.”

…and you were wrong… The Flayer was at the center of a sphere of stars, intercepting some man-thing that was coming at them close to the velocity of light.

“At really high speeds they would have to know how to burn proton cosmic rays—an unpleasant diet.” Grraf-Hromfi got an amused ripple of ears when he added that this might be to the taste of a herbivore.

…yes, and the monkeys have managed to thrive on that unpleasantly lethal diet…

“Those are engineering details and I presume they can be mastered. Ramscoops are a primitive solution and we’ve never used them, so we know little of the details. The major problem is not an engineering one—it is a flaw in the concept. A fusion funnel cannot attain high accelerations, first because it is fuel-starved, and second because reaction drives produce inertial acceleration. How do you build a gossamer funnel that can take even one gravity of inertial acceleration?”

…but at a fifth of a gravity, year after year…

Grraf-Hromfi did not mention in his lecture that a fighting kzin warship could accelerate at sixty gravities with the pilot floating in his cockpit and thus reach its maximum cruising speed in about five days, because all of his officers knew that. “How long would it take this funny-funnel to attain six-eighths the velocity of light?”

“Six months?” ventured a bored officer who leaped to conclusions before.

“More like eight-ten years—with most of that time spent at low velocity. When will it reach Alpha Centauri?”

“About the time the Fifth Fleet has occupied Man-home,” said Long-Tooth-Son with a grin for the poor beasts.

…but it is here and the Fifth Fleet hasn’t even started yet…

“That’s a reasonable estimate. I’d like to remind you that these pictures are more than four years old.”

…it took them only nine plus years to get here…

“The monkey-funnel is already out of range of both the First and Second Black Pride. But even after all this time”—the 4.3 years the Pride’s message took to reach Alpha Centauri—“the ramscoop will still be close to Man-sun and just beginning its journey. It is not something we’ll ever have to worry about. We’ll keep an automatic tracker looking for it—that’s our duty—but I doubt if we’ll ever sniff it again. The monkeys will decelerate and sulk around outside Alpha Centauri well out of our range.”

So even Grraf-Hromfi could be dead wrong.

Trainer-of-Slaves did a calculation on the Sensor’s data-link. The automatic tracker had detected the first trace of the ramscoop two-hundred light-days out—yet years earlier than expected. Which meant that its maximum speed was far higher than kzin engineers had anticipated.

Kr-Captain finished his trajectory plot and put the Flayer-of-Monkeys on automatic. Turnaround was in twenty-three hours. “Sherrek’s Ear gave us orders to be creative.” He meant that they were unarmed.

“Best little mechanic in the galaxy sitting right beside me,” said Trainer-of-Slaves.

“So how are we going to kill this what-ever-it-is?”

“We may not have to. Grraf-Hromfi proved that a monkey can’t stay alive in a ship moving at that speed—cosmic sleeting.”

“Give old red-mane an ear,” he purred sarcastically. “We don’t have to fight because the enemy has already suicided! A nice philosophy until a monkey leaps out of the funeral pyre.” He returned to a commander’s inflected spits and growls. “We shall assume they have a gravity polarizer shield and are still alive.”

“A gravity shield is the same as a gravity drive. Then they wouldn’t need a ramscoop.”

“What’s a ramscoop?”

“A magnetic funnel that collects interstellar hydrogen and ejects helium as reaction mass.”

“Is a monkey going to stand at a porthole and shoot arrows at us?” Kr-Captain flapped his batwing ears.

“Maybe the magnetic field protects them,” suggested Long-Reach, two arm-slits speaking in unison.

“Slave! Shut up,” growled Kr-Captain.

“Does he play cards?” whispered the arm nearest the relaxed ears of Trainer-of-Slaves.

“Don’t eat your