“Let’s tighten it up, Guns,” Randall drawled. “Otherwise we’re going to have a long day on the range.”
“Sorry, sir,” Ensign Girard stammered. “I’m on it!” He fired again. A little more than ten thousand kilometers away from Hector, the kinetic cannon’s ten-kilo solid shot slammed into the drone’s armored side. Fortunately for the drone, the practice round—or “blue shot,” in Commonwealth Navy parlance—was built to shatter and dissipate most of its energy on impact. A real war shot from Hector’s main battery would have delivered energy comparable to a small nuclear explosion, and not even the toughest synthetic alloys and nanoengineered armor could stand up to that kind of abuse. The practice round still hit with enough force to crack one of the drone’s replaceable armor plates and knock the robotic vessel into an end-over-end tumble; the drone began to flash its I’m dead beacon.
“Target Alpha destroyed,” Sikander reported with a note of satisfaction. He couldn’t help it; the little boy in him liked playing with the biggest firecrackers he could get his hands on, and the Mark V kinetic cannon was a very big firecracker indeed.
Hiram Randall promptly deflated whatever momentary satisfaction he might have felt. “About time,” the operations officer drawled. “Three salvos is two too many.”
Sikander suppressed a sharp retort. The firing range was supposed to be challenging, and the drone operators tried hard to make shots miss. Besides, Girard was a gunnery officer, not an ops officer, and that meant it was Sikander’s place to come down on the young ensign, not Randall’s. He’d intended to keep quiet and do a lot of watching on his first live-fire shoot with his team, but he certainly didn’t like another officer chastising one of his new subordinates. Or does Randall think he needs to do my job for me?
Sometimes the best thing to say was as little as you could. “Aye,” he answered, mostly to let Captain Markham—and Ensign Girard—know that he’d heard the criticism but wasn’t about to add to it. Markham said nothing, but Sikander was sure she was paying close attention. As for Girard, Sikander couldn’t see his face from his battle couch, but he thought he could make out a flush coloring the younger officer’s neck as he waited for his orders.
“New target, target Bravo, bearing three-three-five, range twenty thousand k,” Sublieutenant Keane, the sensor officer, reported. He was stationed on the right-hand side of the bridge, forward of the tactical officer’s position. “New target, target Charlie, bearing one-zero-zero high, range fifteen k.”
“Commence tracking targets Bravo and Charlie,” Randall ordered.
“Let’s get ready to split our fire,” Sikander told Girard quietly, making a point of keeping his voice unexcited. He tagged the new icons on his board, marking Bravo for the forward mounts and Charlie for the aft mounts. “Take your time, and let the targeting system steady up just a bit more on the firing solution. At this distance we’re not getting good returns on a small target like a drone.”
“You’ve done some shooting with the Mark V board, sir?” Girard asked.
“I just finished the refresher course at Skye,” Sikander replied, referring to the Navy’s gunnery school. He had to work twice as hard on his technical proficiency as a native-born Aquilan; if he was anything less than very good, his fellow officers might wonder whether he was displacing a more qualified officer for political purposes. Fortunately, he’d always had a good feel for shooting, whether it was a hunting rifle or a target pistol. Targeting computers shot far faster and more accurately than humans, but enemy helmsmen had a way of never being quite exactly where a computer predicted. Human intuition and anticipation in just the right amount made a noticeable difference in the accuracy of most combat shooting. “Relax, Mr. Girard. This is the fun part of the job.”
Girard glanced over his shoulder, startled, and managed a weak smile. “Yes, sir.”
“Main battery, engage target Charlie,” Lieutenant Commander Randall ordered.
“Engage target Charlie, aye,” Sikander responded, and keyed the engage icon on his board. He glanced back to Girard. “Hit him just when he finishes a jink. Fire when you’re ready.”
“Commencing fire,” Girard reported. He pressed the fire button, and once again Hector’s hull quivered and thrummed, this time from somewhere a little aft of Sikander’s station, as the kinetic cannons opened up. Girard’s first volley missed again—not entirely surprising, since it was a significantly longer shot than Alpha, and Hector continued to maneuver. But the ensign’s second volley scored a direct hit and hammered the small drone.
“Target Charlie destroyed,” Sikander reported.
“Very well. Engage target Bravo,” Randall ordered.
“New targets Delta, Echo, and Foxtrot up on the board!” Sublieutenant Keane announced.
“Engage target Bravo, aye,” Sikander acknowledged. He keyed the engage icon and started figuring out how to assign the ship’s cannons to the next batch of targets. Ensign Girard hunched closer over his console, concentrating intently on the task at hand; the atmosphere in the combat center grew tense as more targets began to appear, and the pace of the exercise rapidly increased.
For the next twenty minutes, the cruiser drove aggressively through the firing range, hammering first one drone and then another as the range operators presented a dizzying array of targets for Hector’s main battery of K-cannons. They were relatively simple weapons; the principles had been worked out more than a thousand years ago. A kinetic cannon was simply a very powerful coil gun or mass driver, a tube ringed by electromagnets that accelerated a hunk of metal to the highest speed possible. But, as with so many things, the devil was in the details, and design trade-offs forced difficult choices on weapon designers. Unlike a gunpowder cannon of ancient Earth, a kinetic cannon wasn’t measured by the heft of its projectile—its power was really a function of the velocity the cannon could impart. High velocities meant more impact energy and a reduced flight time for the kinetic round. The longer it took a round to reach its target, the more time the target had to detect the incoming round and dodge the attack. In general, flight times of more than seven or eight seconds were very unlikely to result in hits, unless the target was completely surprised or unable to maneuver. A battleship-caliber kinetic cannon threw rounds close to five thousand kilometers per second, so its effective range was perhaps thirty-five or forty thousand kilometers. A destroyer’s smaller K-cannon might only achieve 2,000 kps, which meant that its effective range was more like fifteen thousand kilometers. As a light cruiser, Hector carried K-cannons that fell in between the two, and threw metal at a velocity of a little more than three thousand kilometers per second; she fought most effectively at ranges of twenty-five thousand kilometers or less.
However, velocity wasn’t the only consideration for kinetic-weapon design. There was actually such a thing as too much velocity. A K-round traveling too fast might punch completely through its target, a less damaging interaction than transferring all of its staggering energy into whatever it hit. After all, any of the projectile’s energy that it retained after passing through the target was energy that did not get used to break things inside the target. A Mark V round fired at full power against an unarmored freighter would leave two neat, round five-centimeter holes in the freighter’s sides unless it happened to hit something big and heavy, such as an engine casing or a structural frame, in the target. But slowing down the shot of course increased flight time and decreased effective range. To counter this, kinetic projectiles came in “hard” armor-piercing rounds and “soft” general-purpose rounds, which were intended to squash and fragment in the moment of impact and therefore dump as much energy as possible into whatever they hit. Soft K-rounds were soft only in the most relative sense of the word, of course—if you fired taffy at 3,000 kps into a steel hull, you’d still punch a hole in it.