Marco and Rada were hunched over the computer in the family room when the message arrived from their son, Nate: “Upper Beta. With a great alcove. Very happy.”
They exhaled with relief. Nate had received his berth at the international base on Jupiter’s moon Callisto.
“He wanted the Beta habitat,” said Rada. “He thinks it’s better than Alpha.”
“And he must prefer ‘upper’ Beta over ‘lower’ Beta, whatever that means. Maybe the view of Jupiter is better?”
“I doubt it. Every room has a million-dollar view.” Callisto was tidally-locked, and the habitat always faced the planet. “He probably didn’t care which level. I think he was just sharing additional details, like the alcove.”
“There must be some reason he prefers the upper level, or else he wouldn’t have mentioned it. Why waste the characters if it wasn’t important?”
Bandwidth limits bedeviled the loved ones of Callisto crewmembers. For much of the moon’s seventeen-day orbit, communication lines between Earth and the habitat were blocked either by the moon’s backside or by Jupiter itself. Someday, a relay satellite would bridge this gap. Until then, clear communications were possible only near quadrature—when the moon was, from Earth’s perspective, to Jupiter’s left or right. But during those short windows, the massive volume of mission data held priority. So bandwidth for personal messages was severely restricted—just forty-eight characters per message.
Rada sighed. “Is that really what you want to waste our reply on—upper and lower levels?”
“No,” he agreed. “How long do we have?”
She checked her watch. “Almost ten minutes.”
“All right.” Marco cracked his knuckles and flexed his fingers over the keyboard. “How about we start this way: ‘Mom and I—”
“No,” she interrupted. “You don’t need to waste space on things like ‘Mom and I.’ Nate knows it’s from us. You don’t even need to say ‘we.’ That’s assumed.”
“Fair enough,” conceded Marco. “But then why did he say ‘a’ great alcove? If he’d just said ‘with great alcove,’ he’d have saved a character—actually, two characters including the space. That plus the other four could have been an additional word.”
Rada rolled her eyes. “You’re overthinking this.”
“Come to think of it,” he continued, “Nate didn’t use all forty-eight characters. His message is just forty-four.”
“He probably just stopped at a convenient place.”
“Or maybe he’s trying to send some sort of subtext by not using all of his characters?”
“Let’s stay focused,” she urged.
“And why say ‘with’ great alcove? He could have just said ‘great alcove.’ That’s another—” He counted on his fingers. “Five characters. If you combine them with the unused four and the two from ‘a,’ he’d have eleven characters available if he’d just written ‘Upper Beta. Great alcove. Very happy.’”
“Enough,” Rada snapped. “This is pointless.”
But Marco was on a roll. “And why the periods? Leaving them out would have freed up three more characters. So fourteen available to say something else.”
“That’s it,” she muttered. “You’re done. Get away from the keyboard, I’m doing this myself.”
Marco rolled his chair aside. “I’m telling you, something’s wrong,” he insisted. “Nate must have known that I’d begin ‘Mom and I,’ and that you’d make your point about the unstated parts.”
“I’m not listening,” sang Rada as she typed a response.
“Furthermore,” Marco persevered, “he must have anticipated that I’d take the logic to the next step and notice that he wasted fourteen characters. He only gets to communicate with us once a week, and he leaves a third of his space unused? Doesn’t make sense. Unless there’s something else—a hidden message, encoded in the unused characters.”
“You’re unbelievable,” muttered Rada as she finished composing her reply. “There’s only two minutes left.”
“A message in the negative space,” rambled Marco. “Like the optical illusion of two faces that create the outline of a vase in the emptiness between.”
“Do you want to look this over before I send it?” demanded Rada.
But Marco didn’t hear her. “A message, fourteen characters long, so secret and powerful that he needed to conceal it,” he mused. “What could it be? ‘Get me out of here’? No, too long. Wait, without the spaces—‘getmeoutofhere’—that’s fourteen exactly.”
“Sixty seconds or we miss our window.”
Marco gazed out the window, steepling his fingers and murmuring to himself. “But that has no spaces. That’s inconsistent with the rest of the message. A fourteen-character phrase including one or more spaces… twenty-seven to the fourteenth. But most of those aren’t valid English words. I could write a program…”
“Time’s running out,” growled Rada.
Marco rubbed his temples. “‘Food repulsive’? That fits, but it doesn’t explain the secrecy. There must be a reason for sending the message in a hidden code.”
“Thirty seconds.”
Marco frantically waved his hands. “Oh my God—he must be on some sort of secret mission, sending hidden messages to his handler.”
“Twenty.”
“Um, um—oh, I’ve got it!” Marco cried. “‘Asset acquired’! That’s it! That’s the message!”
“Time’s up,” Rada announced.
“But what the hell is Nate doing out there, on a secret mission sending coded messages about acquiring assets? What kind of assets? Military secrets? Is he trying to turn his foreign crewmates? Is he an undercover spy?” Marco’s eyes widened and he stared at Rada with horror. “Is he passing a secret spy message to—”
“I’m sending this now,” Rada interrupted, and pressed enter. “Marco, you need therapy.”
§
Forty-three minutes later and three hundred ninety million miles away, in the comm center at the Callisto habitat, Nate read the message from his parents: “Terrific. All ok here. Miss you. Love.”
He stared at for a moment, and then counted the characters. Thirty-eight—ten left unused.
Damn it, he thought. That could only mean one thing: “Dad knows!”
Ron Fein is a Boston-area public interest lawyer, writer, and activist who writes science fiction, fantasy, horror, mystery, and comedy. His work appears in Nature, MetaStellar, Daily Science Fiction, Nonprofit Quarterly, Factor Four, Mystery Tribune, and McSweeney’s Internet Tendency. Find him at ronfein.com, on Mastodon @ronfein@masto.ai, on BlueSky @ronfein.bsky.social, and on Threads @ronaldfein.
