The Medusa Chronicles

by Stephen Baxter

  Mo Berry leaned over to Seth. Mo was short, calm, with an economy of motion: classic test pilot. Now he murmured, “Told you. Chief’s office on Sunday—bandit country, Tonto.”

  Seth didn’t feel like laughing. He glanced out of the window at a deep blue Texas sky, over the green lawns and blocky black-and-white buildings. Only a couple of hours ago, he and Pat had been planning to pile their two boys into the car and go sailing on Clear Lake, one of their first expeditions of the year. Now this.

  And Seth Springer had come a hell of a long way to be told he had lost his chance at the Moon, just like that.

  Seth was thirty-seven years old, and had committed his life to NASA. He’d been born into a service family, and his own first port of call had been the Army, passing through West Point. But with a love of flying that had come to him from who knew where, he’d soon gone across to the Air Force. He’d seen duty in France, making flights over green river valleys that were rehearsals for Cold War combat. But an itch to excel had driven him to a posting at the USAF’s test pilot school, at Edwards Air Force Base in the Mojave Desert, all Joshua trees and rattlesnakes and rocket planes.

  But even that hadn’t proven enough when NASA had started recruiting astronauts. Too young for the initial cadre that flew Mercury, Seth had scraped into NASA’s third recruitment round in June 1963.

  Before the disaster of the Apollo cabin fire in January, Seth believed he had got himself into a good place here. He had become an expert in guidance and navigation systems. He’d backed up one Gemini flight—the one flown by Mo Berry—and he didn’t begrudge that. Mo was a little older than Seth, a Navy man who had seen combat in Korea, and had made an earlier NASA recruitment round. Despite his lack of seniority, Seth was already in the crew rotation schedule drawn up by Deke Slayton, head of the astronaut office, and if all went well he would at least get to fly one of the early Apollo test and development missions. If things progressed beyond that, he ought to get a seat on one of the lunar flights themselves. That was what he’d devoted his career, hell, his whole life, towards.

  And now this stuffed shirt was telling him that all this was gone? Just like that?

  “Sir—Mr. Sheridan—”

  “Shucks, call me George, everybody else does. And we’re going to get to know each other pretty well in the next sixty weeks or so.”

  “Sixty weeks . . . ?”

  Mo said sombrely, “Look, is this something to do with the fire?”

  Everybody was sombre when they spoke of the fire, and the 27th of January was a date that would be forever etched into NASA’s collective memory. Some short-circuit had ignited the oxygen-rich atmosphere inside a prototype Apollo capsule, killing three astronauts, holing the lunar programme itself below the waterline, and sending everybody involved with NASA and its contractors into feverish recovery mode.

  But Sheridan said, “No, son, it isn’t the fire. It sure doesn’t help, though, that this has landed in the middle of that fallout.” He plucked a cigar from a case and began the elaborate ritual of unwrapping it, cutting it, lighting it. “Because, while Apollo’s big, it’s nothing as big as Icarus is gonna get.”

  And that was the moment Seth Springer first heard the name that was going to shape the rest of his life.

  Mo asked, “Icarus? What’s that?”

  In answer, Sheridan pulled a copy of the previous day’s New York Post out of his briefcase. The cover had a still from the old movie When Worlds Collide, and a blazing headline:

  KILLER SPACE ROCK DOOM

  While the astronauts tried to take this in, Sheridan dug into his briefcase once more, and produced a photograph of a hole in the ground. “Recognise this?”

  “Sure,” Mo said. “Meteor Crater, Arizona. We trained in there—along with a few other holes, including some dug out by nukes.”

  “You know what it is? How it was made?”

  “Impact by a meteor,” Seth said.

  “As the name suggests, Tonto,” Mo said dryly.

  “You know all about impact craters, right? Because you’re going to be crawling all over them on the Moon in a couple years’ time. As for Meteor Crater, according to the notes I have, a rock about fifty yards across made a hole in the world that’s the best part of a mile wide. That was a long time ago, though. Now take a look at this.”

  He showed them a photograph of a domed building against a starlit sky.

  “Palomar,” Seth said immediately.

  “Right. World famous observatory in San Diego County.” Sheridan consulted a briefing note from his case. “In June 1949, an astronomer called Walter Baade made a discovery, a streak of light on a photograph taken with a Schmidt camera, and don’t ask me what that is. The streak—the mass that moved across the view field during the exposure—turned out to be an asteroid, a new one. But not just any asteroid. Most of those babies drift safely around out in the asteroid belt, which is somewhere beyond Mars—am I right? This one, when Baade saw it, was only about four million miles from Earth.” He produced a chart of the object’s orbit, a diagram the astronauts immediately understood: an ellipse that cut through the circles of planetary orbits. “And they called it Icarus.”

  Mo leaned forward, fascinated. “So this rock follows a very eccentric orbit. It goes all the way out to the asteroid belt at aphelion, then dives closer to the sun than Mercury, at perihelion.”

  Sheridan eyed him. “At ap-ho-what now?”

  Seth grinned. “White man speak with forked tongue. Farthest and nearest to the sun, sir.”

  Mo looked up. “No wonder they called it Icarus, with all that sun-diving. And no wonder it comes close to the Earth. It cuts right across our orbit—well, it would if it was in the same plane.”

  “Right. This baby travels around its orbit in a little more than a year, and mostly Earth is nowhere nearby. But every nineteen years it comes close. And the closest approach is always in the month of June, for some reason.”

  “Nineteen years,” Seth said. “So after 1949 . . . June 1968. That’s the next encounter. Next year.”

  “Right,” Sheridan said. “But again, it should come no closer than four million miles.”

  Seth said, “Should come no closer . . . ?”

  Sheridan nodded. “What I’m about to tell you is classified. Wartime, you know, I worked for RCA, Radio Corporation of America. Honest war work. Stayed with them after the war when they developed what became BMEWS—”

  “Ballistic Missile Early Warning System.”

  “Very powerful radar. NASA has been working with the Air Force on more powerful systems yet. You can see the application for space research. You could track craft in deep space, manned or otherwise—”

  “Ours or theirs,” Mo said evenly.

  Sheridan looked at him steadily. “Best not to speculate, airman. Anyhow, a couple of weeks back we decided to try to find Icarus, as a test. It’s a nice big target, we know its path, and although it’s a hell of a long way away just now, we figured we should get an echo back from it.”

  “But you didn’t,” Seth guessed.

  “No, we didn’t. Damn thing took some finding, in fact, and when we did find it and tracked it a little to figure out its new path—”

  Mo asked, “How the hell can an asteroid have changed course?”

  Sheridan shrugged. “Your guess is as good as mine. Maybe Icarus took some kind of hit in the asteroid belt. Like a kiss on a pool table.”

  Seth thought he saw it, in one big flash. “It’s going to hit, isn’t it?”

  Mo looked shocked. “Shit on a stick, Tonto.”

  “That’s why we’re talking about this. It won’t miss the Earth by four million miles this time. It’s going to hit—my God, in June next year?” That month had a particular significance to him and it took him a moment to place it. It would be when Joseph, his older son, would be finishing his first year at school . .
.

  “There’s your sixty weeks,” Mo said grimly.

  “You got it,” Sheridan said.

  “And if this thing does hit . . .”

  “Remember Meteor Crater? Dug out by a rock that was fifty yards across? Icarus is a mile across. Most likely impact point is the mid-Atlantic, east of Bermuda . . .”

  In his briefcase of horrors, Sheridan had some preliminary estimates of the consequences. Seth was appalled. The rock would unleash twenty, thirty times as much energy as an all-out nuclear war. A crater maybe fifteen miles across would be punched in the sea bed. Ocean waves hundreds of feet tall would scour the Caribbean, Florida, and the Atlantic seaboards of America and Europe alike. And with maybe a hundred million tons of rock vaporised and hurled up into the atmosphere, there would be a sun-screening layer of dust in the air that might persist for years, creating a deadly winter.

  Sheridan was watching them, gauging their reaction. “I have the feeling you guys are getting it a lot faster than I did. Took some persuading for me to accept this wasn’t just some tempest in a teacup.”

  Mo shook his head. “We have to stop this bastard, sir.”

  “Right,” Sheridan said. “So tell me how we do that.”

  “Us?”

  “You. Let me tell you what happened in the couple of days since we figured this out. We reported up through the NASA hierarchy to the President’s Science Adviser. And he walked in on the President.”

  Mo prompted, “And the President . . . ?”

  “LBJ asked Jim Webb,” the NASA Administrator, “to come up with options for NASA to respond to this. So Jim asked me to handle it, and now—

  Mo glanced at Seth. “And now he’s asking us, Tonto.”

  “At noon tomorrow the President is going to address the nation from the press office, right here at Houston. Why here? Because this is where LBJ’s going to tell the world how this threat from space is going to be countered by the space agency he did so much to set up in the first place. Now, since I got handed this hot potato I already got everybody from MIT college kids to the Mercury Seven working on this. But right now it’s you two I need to rely on, and I picked you because Deke Slayton tells me you’re the best of the best . . .”

  Or, more likely, Seth thought sourly, nobody else was around this Sunday morning.

  “So tell me. How do we use Apollo-Saturn technology to deflect an asteroid?”

  Mo got up and paced. “We’re a nuclear power,” he said simply. “We nuke it.”

  Seth said, “But how do you blow up an asteroid? I guess, in theory, you’d want a bomb big enough to dig a crater the size of the rock itself—in this case a mile. Which is maybe ten times as deep as Meteor Crater.” He got to his feet, walked over Bob Gilruth’s thick pile carpet to a blackboard, wiped it clean of what looked like notes on the Apollo fire, and began to scribble. “As I recall the depth of Meteor Crater is five hundred feet. Mr. Sheridan, do you have the megaton equivalent of the strike that created that?”

  Sheridan looked through his papers. “Ten megatons.”

  “Okay.” Seth scribbled numbers. “So we’re going to need a lot more than that. Somebody in the weapons business must have done studies of energy expended against crater depth—”

  Mo nodded. “So ten megatons bought a five-hundred-foot hole. Shit. Even if it scaled as simple linear, we’d need a hundred megatons: ten times the depth, ten times the power. If it was inverse square, we’d need, umm—” Out came Mo’s slide rule, which he never travelled without. “A gigaton. And if it’s inverse cube—”

  Seth eyed Sheridan frankly. “I think we need a rule, sir. No secrets between us.”

  “Go on,” Sheridan said cautiously.

  “Chances are even a single hundred-megaton bomb wouldn’t be big enough for the job. Now, I’m in the USAF. I know we have fifty-megaton nukes in the arsenal, in development anyhow . . .”

  “I could get you hundred-megs.” Sheridan sighed. “There are programmes that could be accelerated.”

  Mo said, “But not gigatons.”

  “We’ll have more than one bomb. But you’re the spacemen—if you need a gigaton, why not just deliver ten of these things to rendezvous at the asteroid, the way you had your Gemini craft link up in space? Set them off together.”

  Seth was doubtful. “The timing would be critical—one nuke going up a microsecond early would destroy its brothers before they had a chance to detonate.”

  “It’s not just that,” Mo said, his voice abstracted, his slide rule a blur in his hands. “We couldn’t deliver the nukes to the rock in the first place. Not if we’re to decelerate and drop them off. The only rocket we’ve got that could throw a bomb weighing tons across interplanetary space is the Saturn V.”

  “Which hasn’t actually flown yet,” Seth pointed out.

  “Right,” Mo said. “And even with a Saturn V, even with just a single bomb, we can’t slow down. All we could manage is a flyby—a fast intercept.”

  Sheridan rubbed his chin. “Well, that could still work, if you hit the thing with ten nukes at once, fire off ten Saturn Vs. Couldn’t it?”

  Seth said, “We don’t have ten launch pads—”

  “We could build more. Money won’t be an object, believe me.”

  “We haven’t got ten Saturns either. I think we’ll only have—what, five, six?—built by June of ’68 when that thing hits.”

  “We can build more Saturns—”

  “It won’t work,” Mo insisted. “A high-speed flyby in formation, a simultaneous detonation—it’s just too damn complicated. Even if we build the Saturns and the pads. The best we can do is to fire them off in sequence, every few days, have them sail past the rock, and set off their nukes one by one.”

  Sheridan snapped, “And what use is that? You just said a hundred-­megaton warhead is too small to destroy the thing.”

  “So we don’t destroy it.” Mo looked at Seth. “We deflect it.”

  “Deflect?”

  “Think about it. Set the bomb off at the moment of closest approach, just above the surface.”

  Seth stared at him. “My God. Yes. But how much delta-V would that buy you?”

  “Depends on how far out we can go to meet the thing . . .”

  * * * *

  It took them ten minutes of scrawled figuring at the board. Seth was vaguely aware of Sheridan wisely sitting back and keeping his mouth shut.

  Finally they turned to face him. “Okay,” Mo said heavily. “Probably some MIT Brainiac will second-guess all this, but we think we can do it. How much push you’d get from a nuke would depend on how close you could get to the rock, and the nature of the surface and so forth.”

  “Also,” Seth said, “the further out from Earth you meet the rock the better, because the less deflection you need to achieve to shove this thing aside. The systems in Apollo-Saturn have a sixty-day limit, which means we can’t reach Icarus at all before it comes within twenty million miles—”

  Sheridan cut through that. “How many detonations do you need?” he snapped.

  Mo and Seth shared a look. Then Mo said, “Maybe just one could do it. One hundred-meg. Just possibly. But maybe not, and besides a single nuke could fail. We should send up a whole string of the things—”

  “And we’d need some kind of monitoring probes to measure the deflection—”

  Sheridan slammed his briefcase shut. “I’ve heard enough. God damn it, gentlemen, you may or may not have saved the world, but you sure as hell have saved my ass. I’m calling the President.”

  He bustled out, taking the briefcase.

  Mo stared at Seth. “Well, Tonto, now we’ve done it.”

  “What if we’re wrong?” Seth glanced at the blackboard. “If we screwed the pooch . . .”

  “That would be worse than the world coming to an end. But hey, it would all be over soon
enough.” He grinned. “Eat, drink and be merry, Tonto.”

  But Seth didn’t feel like joking. Mo was a bachelor. Seth, suddenly, could only see the faces of his little boys.

  * * * *

  “But despite all the efforts I and others have spent in building up NASA and all its facilities, America is not the world’s only spacefaring power. Perhaps we can do this alone, but every man is stronger with a partner at his side. That’s why I am calling on our Soviet counterparts to come to the table in trust and friendship, so that, in a combined project under the leadership of Senator Kennedy, your experts and ours can work out how best to pool our resources to achieve this monumental goal . . .”

  Twenty-four hours on from a Sunday Seth Springer had expected to spend on a sailing boat, here he was not yards from Lyndon Baines Johnson himself at his presidential podium, with New York Senator Robert Kennedy at his side, and Administrator Webb, George Lee Sheridan and two goofing-off astronauts behind him.

  Mo grinned and whispered, “LBJ, LBJ, how many kids did you save today?”

  Seth shushed him. “Those TV lights, though. Johnson doesn’t even look like he’s sweating.”

  “That’s make-up for you,” Sheridan murmured. “Believe me, he’s sweating on the inside. He doesn’t want to be the president who failed to stop the end of the world. On the other hand he’s not going to stand again in ’68, you know. And who is his most likely successor for the Democrat nomination?”

  “Bobby Kennedy,” Mo breathed. “Whose guts LBJ hates. And who he just named as his Icarus czar.”

  “LBJ! What a guy! With one bound he’s taking credit for establishing NASA, which is now going to save the world, he’s defusing the Cold War by inviting the Russians to join in, and he’s making sure his most realistic successor for the presidency is going to spend the next year staring at rocket equations instead of campaigning.”

  Now the President had finished speaking, and faced a clamour of questions from the floor.

  Sheridan put his heavy arms around the astronauts’ shoulders. “So that’s that. Now let’s get out of here and go find Deke Slayton. I got another assignment for you two . . .”