Lee laughed. “Of course it is. You’re absolutely right. No company would spend this amount of time and expense on hiring some faceless engineer … but it makes a lot more sense when you consider the job you were actually interviewing for.”
“Pardon me?”
“Oh, yeah. You had the Systems Engineer job after the second interview. We kept the process going for you, though. It was partly out of a sadistic desire to watch you squirm, but mostly, or almost mostly, it was because we had to see if you were qualified for a far more important job.”
Nathan was quiet for a long measure as he considered the implications. He had hoped, and feared, for something like this. He took a bite of the succulent, sweet ribs, and wiped his mouth. “I don’t know whether to be flattered or pissed.”
“Too early for either, I’d say. After all, we’ve already filled that Systems Engineering position with someone else and you haven’t gotten this other job yet. You still have more than enough opportunity to screw things up, and then you can be both flattered and pissed. How’s that sound?”
Nathan took another bite of his meat and a swig of his beer. “Sounds like this is the best barbecue man has ever put to plate. And have I mentioned how handsome and youthful you are in person, sir?”
Gordon Lee laughed harder that time and touched his bottle to Nathan’s. “Funny! Clever boy. I have indeed hired some obsequious morons in the past, and it was always a mistake. But you’ve got a genuine sense of humor on you, Nathan, even if it does tend toward the smartass end of the scale. So why don’t I ask you what I brought you here to ask?”
“Suits me, sir, but I think I’ve already been asked and answered every possible question in the book.”
“I doubt that, but here it is. Ready?”
“Absolutely.”
“Mr. Kelley, how would you go about stopping an alien invasion?”
Nathan almost giggled, but stopped himself with a supreme effort. He took a bite of potato salad to cover any further inclination to laugh, though he could not stop an incredulous smirk as he thought about Lee’s question. Eventually, after a long pull on his bottle, he cocked his beer toward his potential boss in a quasi-salute. “That’s quite the zinger.”
“A zinger? What’s a zinger?”
“You know. A zinger’s the big ‘out-of-the-box’ question you get during the interview: If you were a plant, what kind of plant would you be? It’s the question that’s designed to show how innovative you can be, to show how you think: a zinger.”
Lee leaned back and nodded. “Quite the zinger indeed, Nathan. So, how about it? How would you stop an alien invasion?”
Nathan frowned as he thought about Lee’s odd question, and how the entire last few weeks could hinge upon his answer. He stood up and began to pace slightly. Nathan never could understand people who could think sitting down. “Okay, an alien invasion is pretty vague, but defeating any other kind of invasion depends on establishing the parameters of the battlespace. How are these aliens getting here exactly?”
“They’re flying here in a giant rocket or rocket-like contraption from a distant star. They turned around at the halfway point and are decelerating toward Earth, which they will reach in a little over 22 years.”
“My, my, how specific.”
Lee had a drink. “You did say exactly.”
“Well, from what you’re saying, several methods present themselves, but are we even sure this is an invasion?”
“No, we aren’t. Let us say that this hypothetical alien visitor has made no attempt to contact us by signals, or at least there has been no attempt that we have recognized. Also, the distances are so great that there is no way for us to have yet received a response to our own attempts at communication. And since we can think of no reason for this unknown alien species to physically come to us other than for invasion, we are proceeding upon a worst-case scenario.”
Nathan’s pacing was now more rapid, purposeful. “But they are an alien race, correct? So ascribing our own reasoning on them is an uncertain proposition, wouldn’t you think?”
“Of course. Alien race equals alien reasoning. Perhaps they are coming here just to say hello, or to plant poppy seeds and welcome us to the inter-galactic love fest. But why not just contact us with a radio signal? Radio signals are undoubtedly how they discovered we were even here in this universe, so our common sense would seem to suggest that if their intentions were benign they would have called before stopping by for a visit.
“Now, that common sense is really just the laws of motion and thermodynamics expressing themselves in our everyday reasoning, laws that the aliens are also bounded by. If their intentions are benign and they wanted to avoid conflict, it makes sense to make initial contact through signals. Signals move at the speed of light, and are transmitted at a relatively low power level. For a species forced to travel below that speed, think of all the time wasted, all the energy wasted in coming here physically. Signaling us is safer, faster, and cheaper.”
Nathan stopped and looked at Lee. “All right, it’s your game. If you contend that their worries about time and energy expenditure are identical to ours, then their reasoning might be similar to ours as well. So, the only reason for them to come here is that they need something physical from us, like our resources or our women—Mars always needs women, after all. And because they didn’t call first or yet, we have to assume their intentions are hostile.”
“That’s right, but you’re dancing around the question, Mr. Kelley. How do you stop the potential invasion?”
Nathan started to walk back and forth again. “Well, since we’ve established how they’re getting here and confirmed their intentions, the next step is to know the enemy. We have to conduct reconnaissance at the earliest opportunity. How far away are these aliens who are taking 22 years to get here?”
“Let’s say they are about three light-years away now, though they appear four light-years away due to the light speed lag. They would have slowed from 46% the speed of light to only about a quarter c.”
Nathan shook his head with a grin. “You’ve put a lot of thought into this, sir. Okay. Am I assuming we have a magic space drive or current technology only?”
“I am not aware of any magic space drive. Yet.”
“Fine. With current technology, there’s virtually no chance we can field a mission to the enemy within the next 22 years. Chemical rockets have high thrust, but are too bulky and have abysmal specific impulse. Ion engines approach the right efficiency and specific impulse but lack any real thrust or payload capability, and they have the same problem as chemical rockets with endurance. They simply can’t carry enough reaction mass.
“It’s the rocket equation. Since you have to carry your fuel with you, and you have to accelerate your own reaction mass at the same time as you boost your payload, there’s an upper limit to the velocities you can achieve, not to mention that 99% of your ship will be fuel and sacrificial mass. A laser driven lightsail or an Orion-style nuclear pulse detonation engine might work, but that’s still theoretical—not exactly current technology. The furthest we might get within the next 22 years with current rockets, ion engines, gravity assists, et cetera, would be the Kuiper Belt and that’s practically in our own back yard.”
“I would agree, unfortunately. So that’s out.”
Nathan shook a finger at him. “No, sir, not out. It’s just of limited utility, but information is information, even if it’s of the last-minute variety. I would send a spy probe out yesterday with current technology and hope I come up with something better within the next couple of decades. At the same time, I’d invest in some at-home recon. Maybe I could get some time on the Earth based telescope networks, or accelerate development of the SSBA. That baby would make something a couple of light-years away look like something orbiting Mars from an Earth-based scope.” The SSBA, or Solar System Baseline Array, was a system of space-based optical telescopes which would be orbiting throughout the entire solar system in a few years. By spreading the telescopes out and combining their images electronically through interferometry, they would become a virtual telescope with a primary lens the width of the solar system from Earth to Saturn. It would be immeasurably powerful, capable of resolving terrestrial planets in nearby solar systems with ease. It was also obscenely expensive, delayed and opposed as a boondoggle at every turn.