CHAPTER 29
Huntsville, Alabama
Sunday
3:00 p.m. Central Time
Dr. Amy Castlebaum had been poring over the documents that Major Dugan had given her for several hours now. She had put together a few simulations on her computer using Python code and some Matlab, using some programs she’d written over the years. A few modifications here and there and she could simulate rockets, satellites, missiles, suborbital flights, orbital flights, and just about anything that had to do with putting an object of a given mass at any altitude, location, or orbit about the planet. She had programs running that could tell her the maximum “throw weight” of a missile and then convert that into a similar maximum “orbital payload mass” for the same missile being used as a launch vehicle.
She had hand calculations, notes, printouts, and wadded-up pages of scribbled-on engineering paper all around her garbage can where she’d missed it but was too busy to worry with picking them up. She adjusted a plot that was currently on her main computer screen showing two particular trajectories she had managed to reverse engineer from the notes Dugan had sent her. One was an orbit. It was not a very specific orbit as far as she could tell. It was in low Earth orbit (LEO). The calculations were for a perfectly circular four hundred kilometers above sea level orbit at no specific inclination. In other words, it could have been anything in space orbiting the Earth at four hundred kilometers’ altitude. The orbit could be at the equator’s inclination of zero degrees, over Huntsville at about thirty-four degrees, or over the North Pole at ninety. With no data given on the inclination there was no telling what orbit it was. There were LEO satellites in orbits ranging from about three hundred kilometers above sea level all the way out to geosynchronous orbits at thirty-five thousand kilometers, and at just about every single inclination between the poles.
The second plot was a rendezvous trajectory, not an orbit. It originated from sea level. Amy noted that it was from no particular place or inclination either, which meant it assumed equatorial. So, as far as she could tell, this was a launch of a rocket of some sort climbing upward and intersecting with the circular orbit there. The rocket calculations showed a three-stage rocket.
The first-stage burn numbers showed a burn time of two and a half minutes at eight meganewtons of thrust. Those numbers had jumped off the page at her. She’d studied enough Russian launch vehicles in her day to guess that was a Russian-built RD-171 LOX/kerosene rocket engine from Energia. The second-stage burn was just under a meganewton of thrust with a burn time of five minutes and fifteen seconds. That one smelled like a Russian RD-120 to her. Again, another Russian LOX/kerosene engine. The two stages of the rocket supplied enough thrust to take a payload mass of over six thousand kilograms to a four hundred kilometer LEO.
The third burn was sort of a residual calculation. It simply matched the trajectory altitude of the launch vehicle to the circular LEO orbit and showed the burn needed to put the launch vehicle’s payload mass into a circular orbit that matched the spacecraft already in orbit at four hundred kilometers. Amy noted that there was no accounting for inclination cranking and orbit phasing—at least not in the fifty or so pages she’d already made it through. She also noted that there appeared to still be plenty of propellant mass in the third stage for orbit cranking and such shown in the calculations even though Watkins hadn’t done that.
What was clear to her was that this wasn’t an intercept—meaning, the launch vehicle wasn’t making an attempt to shoot down the orbiting vehicle. Instead, this was a rendezvous. The launch vehicle was meeting the already orbiting vehicle, matching its speed, and then mating or docking with it. That was her current working assumption. She had made a significant amount of progress here. But there was a lot still unknown. And she still had about eight pages to go.
She restarted the model to watch it once more just to make certain she hadn’t missed anything. The computer screen showed an image of a generic Earth in the animation window with a red circle above it. The Earth and the orbits were not to scale. She made a mental note that she’d have to explain that to Dugan when she showed it to him. A blue curve started building from the equator at sea level until it matched with the red circle. At three different points on the blue trajectory curve there were asterisks with notes showing “Main Engine Cut-Off,” “Second Engine Start,” “Second Engine Cut-Off,” “Circularization Burn,” and “Rendezvous.” She added a callout block with an arrow pointing at the spot before “Rendezvous”: “Inclination Cranking, Orbit Phasing, and Speed Matching Burns Here.”
As far as she could tell, her graphic matched a napkin drawing and some notes drawn on engineering paper that were part of the images in the PDF file that the dead guy, Watkins, had on his desk.
Amy was pretty certain that this was the intent of the first fifty or so pages of the man’s notes. Now that she had gotten that far, it was time to push on through the next fifty or so pages. Maybe they would help her make sense out of what was going on. At this point, as far as she could tell, there were no calculations for ICBMs or nuclear detonations. But there were many pages left. And Dugan had told her that there were encrypted files on his computer that they had yet to crack. Who knew what was in those?