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.