Space Station Down, page 24
“But…” Kimberly spluttered, “but I’m alive! The terrorists are dead! ADCO’s confirmed that the station’s increasing in altitude—”
“I know. I know. But there’s no possible way to stop the ASATs if they’ve already been launched. No one can stop the missiles once they’re in flight.”
“But why did they give the order? It doesn’t make any sense!”
“I don’t know if there’s any good way to say this,” Tarantino replied, anguished, “but if there was any chance at all that the station continued to deorbit and contaminate American soil, the President was forced to put the safety of the people over saving the ISS. There’s rioting and mass evacuations down here, Kimberly. It’s complete mayhem and he had to stop it.”
“I … I…”
“It’s exactly the same reason why the military shot down USA-193, our own National Reconnaissance satellite back in 2008,” Tarantino said, almost whining. “But this is a hundred times worse. The mere chance that the million-pound ISS carrying plutonium might impact a populated area is causing mass hysteria. People have already died! The President is determined not to allow any more deaths or injuries because of public panic.”
Kimberly couldn’t believe it was true. “But … it’s all perception! No way is the station going to deorbit if I can refuel it. And the probability of it contaminating a populated area is damned near zero.”
“Perception is reality, Kimberly,” Tarantino said. “That’s what the President is struggling with. That’s what’s forced him to make this decision. We don’t agree with it; no one in NASA does. But that’s not the point. The simple fact is that the military has been ordered to shoot down the station to make sure it impacts over the ocean, and this is one of their last windows to guarantee success. After your next orbit the ISS will be out of range, so they have to act now.”
Through the fog of pain that still shrouded her, Kimberly shifted her attention away from their reasons why her own country might shoot her down, to finding a way of ensuring that the ISS would survive.
And keeping herself alive.
“Copy. Now tell me everything you know about this shoot-down.”
Tarantino’s face relaxed minutely, as though he was glad that he’d finally gotten past this seemingly insane shoot-down rationale, and they could go on to the next steps.
He looked down and read from a sheet of paper, “They’ve targeted you on the upcoming pass, a southern Pacific ascent, so you’ve got less than twenty minutes. The ASATs might already be on the way, for a counter-orbital interception.”
Kimberly swallowed. “Okay.” It is what it is. “What else?”
Looking up again, Tarantino replied, “The good news is that our defense liaison has just passed on the info that some of the antisatellite warheads may go ballistic on their last thirty seconds of flight, and won’t be under control by either ground or onboard sensors. Greater than thirty seconds out the ASATs will be maneuvering to intercept the ISS, using their onboard tracking radar. But once that thirty-second mark is hit the warhead is committed to its ballistic path. And even better is that your altitude is above the ASAT performance limits, so they may actually go ballistic sooner than designed.”
“That’s the good news? What’s the bad?”
Tarantino hesitated a heartbeat. “If the warheads are equipped with Aerojet’s throttleable divert and attitude control system, they’ll be receiving updated targeting information from the Aegis cruisers, so they’ll be able to home in on the station during that last thirty-second window. And there’s a high probability that three or more warheads will be used, all launched from the Aegis cruisers in the Pacific.”
“Great,” Kimberly groused.
“Presently,” Tarantino continued, “we’ll only be able to give you crude approximations on the ASAT trajectories from our ground-based tracking systems, so the error bars may be large. That’s all we’ve got, Kimberly. We’re trying to give you a live feed of the tracking data, but it’ll be at least half an hour before that interface is up and running, and that’s too late to do any good. We’re working this on all fronts, and we’ll let you know if Patricia can turn this situation around—at least stop the Aegis cruisers from feeding their updated tracking corrections to the ASAT missiles.”
She closed her eyes. “Understand.”
“And Kimberly…” Tarantino hesitated again before continuing, “I know this is tough after all you’ve already been through, especially with so little fuel. There’s very little time left and communications across all these different government agencies isn’t anywhere near perfect, so don’t count on anybody being able to divert those missiles. We’ll let you know as soon as we hear anything.”
She pushed away from the laptop, leaving the comm channel open, and tried to ignore the pain from the bends. Over her shoulder she answered, “Roger that, CAPCOM.”
He was right, she knew. She didn’t have much time and she had a lot to do. “Go ahead and patch through whatever ground tracking you have.”
She swiveled two additional laptop screens so that she could simultaneously watch them and the video from the ground link. She couldn’t afford to wait for TOPO or any other ground source to finish that interface for relaying tracking information on the incoming warheads; the time lag between their discovering details about the ASAT launch, transmitting the information, and providing their ever-changing orbital parameters would take much too long.
She needed to solve this on her own.
For an instant she felt that all she could do was to rearrange the deck chairs on the Titanic. But then an inner voice said, Screw that! You’ve got a problem to solve. Get to work!
CENTRAL POST, INTERNATIONAL SPACE STATION
Floating before the laptops’ screens, Kimberly assumed that the ASATs would be using an optimized, direct ascent trajectory, much like the Dragon’s approach that NASA’s aborted rescue mission had used earlier. But the ASATs would be traveling much faster, approaching her head-on in a counter-orbital direction, and accelerating at a much higher rate of speed. Their speed would certainly be much faster than the leisurely, one-foot-per-second relative closure velocity of the Dragon—in fact, over fifty-one thousand times faster.
She’d have to program warning alerts into the software, first to calculate when the ISS started its southern Pacific ascent, and then when she had thirty seconds left until impact: when the warheads went ballistic—if they went ballistic. If they did, since the warheads wouldn’t be guided any longer, or making course corrections, they’d be blindly programmed to hit the ISS where the station should be thirty seconds in the future.
Which meant that she’d have half a minute to dramatically change the ISS’s orbital parameters, so the space station would not be where the ASATs calculated it would be. Kimberly had practiced Predetermined Debris Avoidance Maneuvers before, but this PDAM would be like flying by the seat of her pants, especially since she wasn’t even sure of the ASATs’ trajectories.
So her window for evading the incoming missiles was about equal to thirty heartbeats.
Maybe my last thirty heartbeats, she thought.
She knew that the ISS could rise a kilometer in about three minutes, which meant it gained a little more than five meters a second when under thrust, about fifteen feet. So if the fuel line wasn’t obstructed she’d be able to boost the station 150 meters higher in half a minute. In reality, she’d probably be able to goose it only one or two meters per second, max.
It didn’t seem like much, but only a few meters’ gain could make a huge difference, because the ISS modules had a relatively small cross section—except for the solar panels. But a missile would just drill right through the flimsy solar cells and keep on going without damaging any of the modules at all.
But if the ASATs didn’t go ballistic and continued to home in until the final moment, Kimberly didn’t know what she would do. With a tremor of fear, she realized she did know: She would die. Instantaneously.
If she didn’t do anything she would certainly be killed. It’s too much, said a voice in her mind. Who are you trying to kid? They’re going to kill you—and the entire space program, as well.
And would they win? Kimberly snarled silently. You’re going to let them win, to destroy everything we’ve worked for all these years? To put an end to humanity’s reaching outward?
No, she told herself. Never. Not without a fight to the death.
She put all thoughts of failure out of her thinking. She was determined to survive. And to keep the exploration of space alive and flourishing.
She got to work.
Before programming the alarms she first cut the thrusters. She was approaching bingo fuel, and she would need every ounce of thrust she had left to rapidly boost the station out of the missiles’ path. In an ideal world she might have enough fuel to hike the ISS out of the way, but with the fuel line still partially crimped, the engines might not be able to produce enough thrust to prevent the station from being hit.
On the other hand, she wouldn’t have enough fuel now to move the station at all if she hadn’t screwed up de-crimping the tube.
So maybe this was her lucky day, after all.
She snorted. Right. Lucky if you consider that three or more ASAT missiles will be converging on me in less than twenty minutes with one goal in mind: to blow the International Space Station out of the sky.
And me with it.
SOUTH PACIFIC OCEAN: NORTHWEST OF THE SOLOMON ISLANDS
The encrypted signals arrived over the military’s classified MILSATCOM satellite link. All three cruisers received the order simultaneously, confirming to the ship captains what they’d anticipated, what they’d trained for the past several days. The captains were part of the national chain of command, but even as masters of their vessels they didn’t make policy decisions. They executed the legal orders of those appointed over them.
And their orders were clear.
Alarms hooted, and with the firing sequence initialized, all three cruisers executed their mission as one.
Within seconds, an Aegis antisatellite SM-3 missile roared from each ship, smoke billowing from its rocket engines as the kinetic-kill warhead arrowed into a counter-orbital trajectory to intercept the International Space Station.
Almost instantly, each cruiser launched another Aegis Standard Missile-3. However, one of the missiles exploded almost immediately after it cleared its pad, raining flames and debris over the ship.
As the cruiser’s damage control crew moved to suppress the fires and clear the wreckage, a total of five ASAT missiles locked on to their preprogrammed, counter-orbital trajectories and headed upward on their mission.
Thirty-seven seconds after the last missile launched, the captains received an urgent message to belay their launch orders and stand down.
CENTRAL POST, INTERNATIONAL SPACE STATION
Kimberly stayed in Central Post, diligently watching the laptop screens for any sign of the approaching ASATs. She was breathing pure oxygen through a portable mask. Her symptoms of the bends were becoming gentler, bearable. She felt thankful that the BME—the biomedical engineering team—had recommended the pure oxygen treatment as she switched out her nearly depleted bottle of oxygen for a fresh one while keeping an eye on the screens she’d set up.
Normally, the station’s changes in altitude would be controlled by TOPO in mission control, and coordinated days in advance with the Attitude Determination and Control Officer, the desk responsible for the station’s four control momentum gyros. But now as Kimberly prepared to engage in a last-second maneuver, she knew that she’d have to respond by instinct, she wouldn’t have time to validate her decisions through Houston, or have them confirmed by the flight center at Goddard.
She scanned the laptops, not fully trusting the timing alarm she’d programmed into the tracking system’s software. TOPO, the mission control center desk responsible for tracking the ISS’s orbit, had an open line with NASA’s Defense Department liaison, and was able to pass along the status of the approaching warheads, despite such information being highly classified, since it referred to ongoing military operations. But she didn’t rely only on that intelligence for situational awareness. So as she floated in front of her bank of laptops she kept shifting her eyes to as many feeds as she could.
She started to query CAPCOM for another update when one of the laptop screens started blinking red and a raucous clanging noise reverberated from its built-in speaker. As she moved to cut off the ear-splitting alarm, Kimberly wished that the ISS had approach radar—but only incoming spacecraft had that capability. She couldn’t even eyeball the missiles: it was virtually impossible to see them until they were only about two to five kilometers away, much too close for her to react. NASA’s ground-based radars had picked up the incoming warheads, and from the timing numbers scrawling across one of the laptop screens they were zeroing in on her at incredible speed.
A cold chill enveloped Kimberly as she gaped at the dizzying numbers. The missiles were racing toward her in a counter-orbital direction at 17,500 miles per hour. Add that to the station’s own 17,500 mph velocity in the opposite direction around the Earth and you got a head-on collision at 35,000 mph—over 51,000 feet per second—enough to tear the ISS apart.
Her heart pounding against her ribs, her hands clammy, and her throat dry, Kimberly pecked swiftly as a madwoman at the graphical display. She’d integrated NASA’s tracking data with her own algorithm to show a crude visual image of the incoming missiles. Another object appeared on her screen, then another one—and then two more.
They had launched not three, but five warheads, all of them speeding toward her.
Kimberly poised her finger over the icon controlling the thrusters’ fuel line, ready to start the flow of fuel that would engage the engines. Not too soon, she told herself. Steady … steady. Inanely, she remembered a line from her school days: Don’t fire until you see the whites of their eyes.
The warheads were not converging on the station, she knew, but on a future spot in the ISS’s projected orbit, where the ASATs’ computers calculated the station would be located a mere few seconds from now.
NASA’s feed showed the five warheads flying in graceful shallow arcs, neither jinking nor otherwise behaving like anything except dogged, determined cheetahs utterly fixated on their prey. They moved in undeviating trajectories across the screen, their positions updated by her estimated timing program.
Kimberly knew that her software was automatically updating the incoming warheads’ position and velocity. The laptop was using that data to instantly project each ASAT’s impact point. Simultaneously, the software she’d written predicted when her thirty-second window would open for her to engage the thrusters and maneuver the station out of the warheads’ way. She’d know within seconds if the ASATs would go ballistic or if they would continue to home in on the ISS, making last-second course corrections right down to the moment of impact.
Silently, she prayed that the warheads would all go ballistic and converge on their predicted target all at the same time. That would mean that in their final thirty seconds they would not be able to maneuver.
But if the missiles didn’t go ballistic, her biggest fear was that she’d engage the thrusters too soon, giving the warheads enough time to change their velocity and intersect her new orbit. Then they’d impact the ISS, no matter what she did.
Seconds count, Kimberly told herself. Microseconds count.
Steeling herself, she watched the ASAT warheads converge on their calculated future location of the ISS’s position. Each warhead showed on her laptop screen as a tiny oval at the end of a dotted line. In less than a minute the station would be at that point in space unless she engaged the thrusters. But if she started too soon the ASATs could adjust their velocity to converge on the new impact point.
The longer she waited the more they’d have to change their momentum. She hoped that their final stages were designed more for finessing rather than making any large orbital change.
It was a waiting game. Seconds stretched into eternities. The tension in Central Post ratcheted up unbearably. Kimberly wanted to scream, wanted to shout for help from somebody, anybody. But there was no one except her. She was alone. The thought flashed through her mind that this wasn’t only her own life on the line. The next few moments would also determine the fate of 150 billion dollars’ worth of space infrastructure—and most likely the future of the entire human space program.
The blips showing the five approaching warheads jumped closer to the ISS’s future location with every second as their final-stage rocket engines accelerated them. Kimberly held her breath as the digital clock on the laptop screen counted down the time to her thirty-second window.
Two of the warhead blips turned green. They were within the window.
Kimberly started to engage the thrusters as a third blip went green. Three of the warheads had gone ballistic.
She froze her finger above the console as a burden of fear slammed into her. The other two warheads were making small, last-second course corrections! CAPCOM had said they might have throttleable divert and attitude control systems. Time seemed to hang suspended as she glanced at the clock: twenty-six seconds to impact.
She couldn’t wait any longer. It was now or never. Kimberly punched the fuel line control state to ON, hoping she’d be able to boost away from the three ballistic warheads’ calculated impact point.
She could barely feel the 100 micro-gee acceleration of the station as the thruster engines engaged, slowly pushing the million-pound station higher, a few scant meters every second. On the screen the dotted line displaying the ISS’s trajectory seemed to creep leisurely as it veered slightly off from the old, projected orbit to a new, longer arc.
CENTRAL POST, INTERNATIONAL SPACE STATION
Kimberly’s eyes widened as she watched on the laptop’s screen two of the approaching ASAT warheads blink and make a course correction. They now aimed for the updated future intercept point of the ISS’s new, higher orbit. They would hit in less than twenty seconds.
