Then they showed us the most disturbing government training film in history.

  AN ANIMATED EARTH Defense Alliance logo appeared on the screen, with the capital E and D in EDA morphing into a transparent shield that encircled a spinning blue Earth. The negative space between the legs of the stylized capital A formed the domed head of a Sentinel mech, while the space at the A’s center contained a lidded cyclopean eye, which I knew was meant to represent Moon Base Alpha, the secret Earth Defense Alliance installation on the far side of the moon. I wondered why the real EDA had chosen to include Moon Base Alpha in the crest, since the base itself obviously couldn’t be real. Then I reminded myself—just a few hours ago, I’d thought the same exact thing about the EDA itself.

  The EDA’s Latin motto, Si Vis Pacem Para Bellum, appeared below the crest, then both faded away, leaving a vast field of stars on the screen, as ominous music swelled on the soundtrack. It was the opening track of the orchestral score for Armada, composed by none other than John Williams. When the London Symphony Orchestra’s string section kicked in, I felt the hair on the back of my neck stand up.

  I reminded myself that this was real life.

  I reminded myself to keep breathing.

  On the screen, an early NASA probe drifted into the shot, hurtling through the starry void. It looked like an old backyard satellite dish with three long outdoor TV antennas bolted to its base at right angles. I recognized it as one of the twin Pioneer 10 and Pioneer 11 spacecraft, the first two probes NASA sent to survey our outer solar system. They were launched in the early 1970s, so I knew the footage we were seeing had to be computer generated.

  The camera swung around behind the spacecraft, revealing that it was fast approaching Jupiter. As the gas giant loomed on the screen, a voice began to speak over the music on the soundtrack. Lex and I both gasped with recognition, along with a chorus of others in the auditorium. We all recognized the voice instantly, even though its owner had been dead for nearly twenty years.

  It was Carl Sagan.

  And the first words he spoke contradicted nearly everything I’d ever been told about our current understanding of the universe.

  “In 1973, NASA discovered the first evidence of a nonterrestrial intelligence, right here in our very own solar system, when the Pioneer 10 spacecraft sent back the first close-up image of Europa, Jupiter’s fourth-largest moon. It was received and decoded at the Jet Propulsion Laboratory in Pasadena, California, on December 3rd at 7:26 p.m. Pacific standard time.”

  It was immediately obvious to me why the EDA had recruited Dr. Sagan to narrate this film. Sagan’s assured and familiar baritone imbued each word he spoke with the weight of cold, hard scientific fact—which was incredibly unsettling, because Sagan had been a driving force in humanity’s search for extraterrestrial intelligence since the 1960s. If NASA had discovered aliens back in 1973 and Sagan had helped conceal it from the world for the rest of his life, he must have had an incredibly compelling reason for doing so—but for the life of me, I couldn’t imagine what it could have been.

  Maybe the EDA had somehow edited or simulated Sagan’s voice for this film? Or maybe they had blackmailed him into doing it? Shit, for all I knew, the EDA might have a secret lab beneath the Pentagon filled with Axlotl Tanks, where they mass-produced Sagan and Einstein clones around the clock like Honda Accords.

  Then a video image of Dr. Sagan himself appeared on the screen, and I stopped wondering whether it was really his voice. The footage was clearly from the ’70s: Sagan looked younger than he did in the original Cosmos miniseries. He was standing in a crowded JPL control room with a dozen or so shaggy-looking scientists, all of whom were clustered around a tiny black-and-white TV monitor, watching anxiously as humanity’s first close-up photo of Europa slowly appeared on it, a single line of pixels at a time. The right half of the Jovian moon lay in shadow, but the hemisphere on the left was currently in full sunlight, and some faint surface features were already visible there, despite the image’s low resolution.

  As the download approached completion and the rest of Europa’s surface gradually became visible, Sagan and the other scientists began to study the image with an increasing air of confusion and alarm. When the last row of pixels formed and the complete image appeared on the monitor, it revealed that an enormous section of Europa’s icy surface was covered with a giant swastika.

  Frightened whispers and murmured expletives swept through the auditorium. Beside me, I heard Lex whisper, “What the fuck?”

  I nodded in agreement. This was undoubtedly the most unsettling history lesson I’d ever been subjected to—and I couldn’t imagine what could be coming next.

  “That first close-up image revealed the existence of an enormous symbol etched onto the Jovian moon’s surface,” Sagan’s voice calmly explained. “An equilateral cross with all four of its arms bent at perfect right angles—known here on Earth as a swastika—was clearly visible in the southern hemisphere, covering an area of over a million square kilometers. The swastika was so large, in fact, that it appeared slightly warped in that first Pioneer photo, due to the curvature of the moon’s surface.

  “The discovery of this symbol was immediately recognized by NASA scientists as the first concrete evidence of an extraterrestrial intelligence. However, the excitement over this landmark discovery was eclipsed by the debate over the symbol’s potential meaning. For thousands of years the swastika had been used by peaceful cultures around the world as both an ornamental symbol and a good luck charm, until it was adopted by the Nazi Party in 1920, and the atrocities they subsequently committed forever transformed it into an icon of humanity at its absolute worst.”

  “Yeah, why didn’t they slap a yin-yang symbol on Europa instead?” Lex whispered beside me, slurring her speech a bit. “That would’ve blown NASA’s mind.”

  I shushed her, and she let out a short hysterical laugh, then seemed to regain her composure. We both returned our attention to the screen.

  “We had no way of knowing whether or not the beings who had defaced Europa were aware of the meaning the symbol held for us,” Sagan’s voice continued. “Until we had more information, all we could do was speculate about the symbol’s origin and meaning. Our nation’s political and military leaders made the decision to conceal it from the world, fearing that news of its existence would create a panic that might plunge our entire civilization into religious, political, and economic chaos. President Richard Nixon issued a secret executive order that NASA’s dark discovery on Europa would remain a highly classified national secret until it could be studied further.”

  Now I understood why Dr. Sagan and the other JPL scientists had gone along with the government’s cover-up. The alternative would have been to tell the fragile citizens of planet Earth that they’d just discovered a giant Nazi Post-it note orbiting Jupiter. If Walter Cronkite had dropped a bomb like that on the evening news back in 1973, human civilization would have gone collectively apeshit. Planning another mission to Europa under those circumstances would have been problematic—maybe even impossible.

  But there were still a lot of things about this story that bothered me. For one, the details of NASA’s discovery on Europa were giving me a strange sense of déjà vu. It took me a moment to figure out why.

  Since the late ’70s, the official word on Europa from our scientists had been that it was one of the most promising potential habitats for extraterrestrial life in our solar system, due the vast ocean of liquid water beneath its surface. As a result, Europa had been a popular setting with science fiction writers ever since. I could think of at least half a dozen stories that involved the discovery of alien life on Europa—most notably the Arthur C. Clarke novel 2010, his sequel to 2001: A Space Odyssey. Peter Hyams had directed an excellent film adaptation of 2010 back in the ’80s, and the movie version ended with a highly advanced alien intelligence using HAL-9000 to send humanity a mass text message warning us to stay the hell away from Europa.

  Attempt no landing there.

  There was also something familiar about an alien first-contact message that contained a swastika. After racking my brain for what seemed like an eternity, I realized the answer was staring me in the face—Carl Sagan himself had written a similar scenario into his first and only science fiction novel, Contact. In Sagan’s story, SETI researchers receive a message from an extraterrestrial intelligence that contains a copy of the first television broadcast from Earth the aliens ever intercepted, which turns out to be footage of Adolf Hitler’s opening speech at the 1936 Summer Olympics in Berlin. One of the most memorable moments in both the book and the film adaptation occurs when the SETI scientists decode the first frame of the alien video transmission and discover that it contains a close-up image of a Nazi swastika.

  The events unfolding on the screen in front of me were different from the tales of first contact described in either 2010 or Contact, granted—but surely those similarities couldn’t be mere coincidence?

  Like Sagan, Clarke had been a NASA insider. It made sense that he too had learned of Pioneer 10’s discovery on Europa and agreed to take part in the cover-up. But then why had both men subsequently hidden kernels of the top-secret truth in their bestselling science fiction novels? And why had the EDA let them get away with it? Especially considering that both of their novels were then adapted into blockbuster films that had exposed this classified information to a global audience?

  As it occurred to me that I’d probably just answered my own question, several high-resolution images of Europa began to appear on the screen, showing its surface in much greater detail. Up close, the moon looked like a dirty snowball crisscrossed with reddish orange cracks and streaks that were thousands of kilometers long. The giant black swastika stood out in stark relief against the moon’s surface.

  “When Pioneer 11 reached Jupiter a year later in December of 1974,” Sagan’s voice-over continued, “its course was adjusted to make a close flyby of Europa, and it sent back much clearer images of the moon and its surface anomaly, putting to rest any lingering suspicions that the earlier Pioneer 10 image had been faked in some way. By this time, NASA was already rushing the construction of a new top-secret probe designed to travel to Europa and land on its surface to study the swastika anomaly up close, and hopefully collect enough data to ascertain its origin or purpose. NASA dubbed this spacecraft the Envoy I, and it reached Europa on the 9th of July, 1976—the day humanity made its first direct contact with an alien intelligence.”

  I had never been so glued to a movie screen in my life.

  A shot of the Envoy I—or rather, another CGI simulation—appeared on the screen, showing the probe as it maneuvered into orbit around Europa, with majestic Jupiter looming behind it. It looked like a larger, less streamlined version of the two Voyager spacecraft NASA launched the following year, with giant fuel tanks and a lander cobbled onto its frame.

  As the spacecraft passed over the huge black symbol, the orbiter deployed its landing module and it began to descend toward the frozen surface.

  The image cut to what appeared to be actual video footage shot by the Envoy lander’s on-board camera during its final approach.

  Seen directly from above and in full sunlight, the giant swastika on Europa’s surface appeared to consist of nothing more than long bands of discolored ice. The blackened sections of ice still reflected sunlight, and aside from the change in its color, there appeared to be no disruption in the pattern of striated cracks and frozen ridges covering the moon’s surface. It looked like someone had slapped the solar system’s largest swastika stencil on the side of Europa and then hit it with a Star Destroyer–sized can of black acrylic spray paint.

  “The Envoy lander set down near the southernmost tip of the anomaly, near what would later become known as the Thera Macula region,” Sagan’s voice-over continued, just as the lander completed its controlled descent and touched down on the surface, with its landing gear straddling the border between the swastika’s edge and the unblemished ice beside it.

  To my shock, a familiar gold disc was attached to the base of the lander. It looked identical to the famous gold records NASA had attached to both of its Voyager spacecraft.

  “A twelve-inch gold-plated copper disc was attached to the Envoy lander,” Sagan explained. “This phonograph record was encoded with sound recordings and images selected to portray the diversity of life and culture on Earth, to serve as a token of peace from our species.”

  After the lander finished unfolding its solar panel array, a jointed robotic arm extended from its underside and began to collect a sample of the blackened surface. The heated metal scoop at the end of the arm dug a furrow into the ice about a foot deep, revealing that it was black at that depth, too. Once the arm retracted, the body of the lander opened up like a metal flower, revealing a torpedo-shaped probe within, with its nose pointed straight down at the ice.

  “The heat generated by Jupiter’s tidal flexing of Europa causes most of the moon’s subsurface ice to remain liquid, resulting in a subterranean ocean that we knew could possibly harbor life, which made it the first logical place for us to search for the beings responsible for creating the symbol on the moon’s surface.”

  I once again marveled at the powerfully calming effect of Sagan’s voice. If James Earl Jones had been chosen to narrate this briefing film, it would have been even more terrifying to watch.

  “Shortly after it touched down, the Envoy lander deployed a cryobot, an experimental nuclear-powered melt probe designed to burn down through the moon’s surface ice and explore the ocean hidden beneath it for signs of extraterrestrial life.”

  The lander slowly lowered the torpedo-shaped cryobot, pressing its superheated nose down into the blackened ice. An explosive column of steam shot up high into Europa’s nearly nonexistent atmosphere as the probe began to melt through the onyx surface, burning a perfect cylindrical tunnel through the ice as it descended, pulled downward by gravity.

  In a few seconds, the tail of the cryobot disappeared beneath the surface, unspooling a long fiber-optic tether behind it that would keep it connected to the lander and its transmitter. Then a cutaway animation of Europa appeared on the screen, showing the cryobot’s progress as it burrowed down through several kilometers of solid ice before it finally made it all the way through the crust and then plunged into Europa’s dark ocean.

  “We lost contact with the cryobot just a few seconds after it cleared the underside of the moon’s ice layer. At first, NASA suspected an equipment malfunction, because we also lost contact with the lander up on the surface at the same moment. But when the Envoy orbiter passed over the landing site again a few hours later, the satellite images it sent back revealed two things: The lander had completely vanished from the surface, and so had the swastika.”

  The film cut to a rapid slideshow of still photos taken by the orbiter. The swastika had indeed disappeared, leaving no sign it had ever been there in the first place. Then the image magnified to show a detailed view of the probe’s landing site. The four impressions left by the lander’s feet were still visible, as was the circular hole the cryobot had burned into the ice—ice that had miraculously reverted to its natural color.

  “Forty-two hours after NASA lost contact with the lander, its radio transmitter came back online, broadcasting on the same top-secret NASA frequency. When its signal reached Earth, we discovered that it contained a brief voice message, apparently sent by the inhabitants of Europa. To our surprise, it was worded in plain English, and spoken in the voice of a human child.”

  A recording of a young girl’s voice began to play on the soundtrack.

  “You have desecrated our most sacred temple,” the child’s voice intoned in a flat, inflectionless tone. “For this there can be no forgiveness. We are coming to kill you all.”

  Even as I shuddered in my seat, something about the message struck me as oddly familiar. It was like something out of a bad science fiction movie.

  Then Carl Sagan’s calming voice-over continued.

  “It was quickly determined that the female voice heard in the alien transmission had been synthesized from one of the brief audio recordings included on the gold record we had attached to the lander.

  “To our dismay, this twenty-one-word message began to repeat on a continuous loop, hour after hour, day after day. The Europans, as we began to refer to them, ignored all of our attempts to respond or explain our actions. For reasons we still don’t understand, it appears they viewed our first attempt to make contact with them as an unforgivable act of war. By sending a melt probe to explore beneath their moon’s surface, we may have unknowingly violated some territorial or religious boundary their species holds sacred. Or the Europans may simply view our species as a threat to their own. We still aren’t sure of their motivations, because all of our subsequent efforts to communicate with them have met with failure.”

  Another wave of nervous chattering swept through the auditorium. I scanned the audience, half expecting someone to flip out, but everyone remained calm and in their seats—including me. The revelation that evil aliens were coming to try to wipe us out didn’t send anyone into hysterics or create a panic—and I thought I understood why. For decades, we had all been inundated with a steady barrage of science fiction novels, movies, cartoons, and television shows about aliens of one kind or another. Extraterrestrial visitors had permeated pop culture for so long that they were now embedded in humanity’s collective unconscious, preparing us to deal with the real thing, now that it was actually happening.

  “We began to send more probes to Europa, numbering in the hundreds, but nearly all of them were lost or destroyed shortly after they reached the moon’s orbit. However, through trial and error, we were eventually able to place a handful of remote surveillance platforms on several of Jupiter’s neighboring moons, allowing us to closely monitor Europa without being detected. Their cameras sent back the following orbital surveillance images.”