Eagle Station

“New radar contact,” the station computer announced abruptly. “Bearing zero-five-one degrees. Altitude two hundred miles. Range three thousand, five hundred miles. Closing velocity nine point five miles per second. Contact is friendly. Repeat, friendly. Positive IFF.” The S-29 had just crossed their radar horizon.

And then a familiar-sounding voice crackled over through Reynolds’s headset. “Eagle Station, this is Shadow Bravo One. Do you copy?”

A grin creased his face. “Five by five, Bravo One. Welcome to outer space, Dusty,” he radioed.

“Thank you kindly, Eagle,” Colonel Scott “Dusty” Miller replied. He was the Space Force’s first S-29B-qualified command pilot. “Say, Mal, are your boys and girls ready to dance?”

“We may be a little out of your league, Bravo One,” Reynolds said, still smiling to himself. “That peashooter two-megawatt laser you’re carrying won’t be in range for a while yet… and our rail gun can zap you the moment you cross our visual horizon.” He glanced down at his display. “Which is in just about fifteen seconds from now.”

Miller’s reply sounded equally amused. “Well, that’s mighty bold talk for a man strapped into a fat, floating tin can, Mal. Fight’s on!”

“Roger that, Bravo One. Fight’s on,” Reynolds acknowledged. He cued the intercom again. “All personnel, stand by to engage that S-29 spaceplane in simulated combat.” He looked across the compartment toward Allison Stewart. “Anytime you’re ready, Captain.”

She nodded. “The target is in visual line of sight. Our radar is locked on. Handing off tracking data to—” She broke off and muttered, “Well, crap.”

“Clarify that!” Reynolds demanded.

“Sorry, sir,” Stewart said, turning faintly red with embarrassment. “The radar can’t develop an acceptable fire control solution. The S-29 is maneuvering erratically, using its thrusters — not its main engines.”

Reynolds stared down at his own display in surprise. The icon representing Dusty Miller’s spaceplane jittered wildly, yawing, rolling, and pitching through all three dimensions as its thrusters fired in short pulses. And try as it might, Eagle Station’s powerful X-band fire control radar was having real trouble figuring out exactly where the S-29B would be when the Thunderbolt rail gun’s plasma shot arrived.

“Damn, that’s clever,” he muttered.

Once it was fired, the weapon’s plasma toroids could not turn or change course. They streaked along a straight, undeviating path until they lost coherence roughly one second, and six thousand miles, later. If the target wasn’t where the computer said it would be along that path, the shot would miss. As the range dropped and the time of flight for the plasma projectiles diminished, the job of making that calculation should get easier. If nothing else, once flight times dropped to just fractions of a second, the S-29’s thrusters might not be able to move the spacecraft out of the way in time.

He looked back at Stewart. “How long before that spaceplane gets within striking range of this station?”

“A little under five minutes, Colonel.”

He nodded. “Okay. Can you run a pattern analysis on the S-29’s observed evasive maneuvers? See if you can crack whatever program they’re running, so our computer can predict its next moves?”

She chewed her lower lip, deep in thought. “I can try, sir.”

Left unspoken was the probability that whatever automated maneuver program Dusty Miller and his Shadow crew had running was using randomly generated numbers to select which particular thrusters fired and for how long. If it was using the more typical pseudo-random number generators common to many computer programs, the algorithm and seed used might be discoverable… in time. If it was using a so-called true random number generator and extracting randomness from physical phenomena — radioactive source decay, for example — there was probably no way to crack it.

Thinking it through, Reynolds was willing to bet there were hard limits coded into the S-29’s evasion program. You couldn’t leave everything to pure random chance — not on a working spacecraft with set reserves of hydrazine thruster fuel. There were also definite limits to the amount of torque and tumbling you could inflict on a spaceplane without harming the crew or risking its structural integrity.

He opened a circuit to Major Ozawa in the aft weapons module. “Ike, I want you to take every possible shot at these guys, understand? Even if you can’t get a solid fire control solution, take the shot.”