Threshold: Chapter Twenty Seven

    Helen stared in stunned amazement, so riveted by the sight in front of her that she forgot to move out of the way; A.J., caught off-guard, bounced into her, shoving her into the cavernous hangar that was home to the alien vessel.

    "Hey, you could at least have moved—" A.J. began, then noticed her expression. "Oh, that's right. It's the first time you've seen the ship in the flesh, so to speak."

    "I'd seen pictures, but… Holy Bug-Eyed Monsters, Batman, that's bizarre," Helen said finally.

    The alien dusty-plasma vessel seemed to float in the center of the vast room—which was ridiculous, given that Ceres did have a significant gravitational field. It took Helen a few moments to spot the cables that were suspending the gigantic hull over the hangar floor. The alien spaceship looked like a beetle held in a spiderweb.

    Vault-like material glinted dully in the bright work lighting, a sheen of metallic luster with hints of structured striations, something like spun aluminum but with a bronze color that somehow carried a bluish undertone. The color shifted subtly depending on the angle of the light, which meant that as you moved around the ship, the hull showed strange, almost-invisible moving patterns. The shape overall was made of sweeping curves in trilateral symmetry, like the ship's makers. There were no sharp edges except the trapezoidal outline of the airlock entryways. It was streamlined and organic-looking, small spikes like points of bamboo shoots curving over areas that looked like ports or vents, surrounding the entire vessel at its midsection. And the size…

    "It's huge," Helen murmured.

    "Well," Joe answered from the other side of the ship, "partly that's because you're up so close and it's inside. Compared to Nobel or Nike it's pretty tiny; mass of the hull and interior bracing and assorted structural elements is about a hundred and ten tons or so."

    Helen blinked; to her, the almost-living, streamlined shape seemed colossal, at least the size of Nike. But she knew that Nike, even empty, massed around two thousand tons.

    "That's a little deceptive, though," A.J. said. "That Vault material is tougher than anything else we've ever seen, and that made it possible for them to make this thing bigger than it might be otherwise. This little beast measures about sixty-five meters long and is about fifteen meters across at the widest part there. And, like Nike or Nobel, it's got a lot of empty space inside. Which is good, because we're gonna need it all."

    "Really?" Helen studied the ship, which was somewhat more elongated in what she thought was the front, coming to three slender points at the very end; the rear of the vessel flattened out into an almost tripartite tail. Somehow it reminded her of a cuttlefish or squid in swimming posture. "There's only six of us going. And you're vandalizing the thing to make more room, it looks like."

    The "vandalism" Helen pointed to was the addition, at the four cardinal points around the vessel's girth, of long backswept rods ending in slightly-curved blocks. The four jarring additions, clearly human-built, were attached just behind the circle of bamboo-shoot shaped spikes.

    "I'll admit they're aesthetically displeasing on this ship," Jackie Secord said, entering the conversation as she exited one of the ship's locks. "However, those four habitat modules will—once we get her outside—extend out and allow us to spin up for gravity, just like Nobel, and we'll definitely need that to stay healthy on the way."

    "And," Joe said, "we will need every bit of space we can get. We can't get nearly as good recycling gear set up for this ship as we could for the ships we had years to design, so we have to take a lot more consumables. Normally we can make do with slightly less than two tons of consumables per person per year, but with the systems we're dealing with… well, I think we'd probably be able to get away with three or four, but I'm going with six, and figuring on at least a three-year trip. So that's nearly a hundred and ten tons of consumables—food, water, and air. To run the ship needs power—lots of it—which is why we're taking the base reactor. That's about seventy tons right there. Add in twenty tons of lander and various equipment, and we're around three hundred tons main payload. And then we need seven hundred tons of fuel capacity."

    "Fuel?" Helen was puzzled. "I thought the point of this dusty-plasma sail was that it didn't need fuel. Well, a few hundred kilograms of dust and gas, but not fuel."

    "True," Joe said, "But to do fast course changes—or to change direction 'against the wind,' so to speak—you need a rocket, or something like it. We may need to do an Oberth around Jupiter, and when we want to come back, we'll definitely want to use that approch to head back in-system."

    "You're talking about a NERVA style drive, like the Nobel, right?"

    Jackie nodded. "Exactly. We're saying 'fuel' but really it's just reaction mass. Heat it up with the reactor, throw it out the back."

    Helen frowned. "But… if I remember right, the base reactor's rated at something like thirty or fifty megawatts. I'm sure that Nobel's engine reactor is a lot more powerful, maybe ten or twenty times more powerful. Is the base reactor going to be enough, Jackie?"

    The dark-haired engineer grinned. "No and yes. If I had to use the reactor straight, no, I could redline it and still only get a pretty puny rocket. I want something close to the real deal. What I can do is basically create the equivalent of a fast-surge accumulator—a big bank of superconducting batteries that gather up a few hours of the reactor's output and then release it in a relatively few seconds. For those few seconds I can essentially pretend I've got Nobel's reactor driving this rocket instead of our base reactor. And I really do have to be able to push the rocket to basically the same level of performance that it would have for Nobel, because I'm going to need to do a real fast burn as we pass Jupiter, if we end up intercepting Odin, or as we pass Saturn, if we just try to beat them to the punch."

    "You can't do it over a longer stretch?"

    "Nope. The whole point of the Oberth maneuver is timing. At perihelion you do the delta-vee burn and depending on whether you do it to speed up or slow down, you either speed up or slow down a lot more than you would otherwise. Basically you're either gaining or losing the energy equivalent to throwing your fuel down the gravity well you're maneuvering in. It's a squared function, so even a relatively small delta-vee will get you a pretty big change."

    She pointed to a huge funnel shape just visible past the flattened fins of the aft portion of the vessel. Helen recognized it as one of the spare NERVA rocket nozzles for Nobel. Meters across, the spare nozzle had been jury-rigged to the rear of the alien vessel. "And that will handle the load just fine."

    "If," Joe noted, now inside the ship, "our calculations are all correct. If that thing's significantly off from the center of mass when we fire, we could be in trouble."

    "That's why we've done the calculations and designs six times, Joe. But we can't wait much longer. Even with all the tricks we can pull off, A.J. doesn't give us more than another six days before there's no way to catch them at Jupiter, and not all that much longer before we would just have to give it up entirely."

    "I know. Just pointing it out. I've crashed before, you know. Twice. I'd rather not do it again, this time almost four hundred million miles from help."

    "You can't launch from inside Ceres, though. Not without using your fuel, right?" That was A.J.'s voice; he was working on the control systems deeper in the vessel.

    "We will use some of the fuel that way. I want to test her before I go out that far. Do I look crazy?" Jackie said. "I want to fire the engine long enough to get into orbit around Ceres. Feynman or Einstein will refuel us—I'm using mostly water, which isn't the best fuel for a NERVA rocket by a long shot but it's stable, easy to get here, and useful for a lot of other things—and then, if everything looks good, we'll take off. If the dusty-plasma drive doesn't work, well, then we go to plan B. That’s B as in blackmail."

    "I could settle for that, if I have to. But I am confident she'll fly," A.J. said. "And we need to think about publicity here. Dusty plasma drive doesn't sound sexy."

    "What would you suggest?"

    He told them. "But I'm waiting until I see it running. I think that you'll agree I'm right, and if so, we've also got the name for our ship."

    Jackie nodded. "Provisionally accepted. We'll see when she launches. How about the gas and dust supply for the sail itself?"

    "Got it. I'd thought of this wrinkle earlier, but the fact that our friends on Odin were actually using it kicked me into getting it set up. We'll be using Faerie Dust for a lot of it. That will give us quite a bit of control over the sail, even more than the Bemmie magnetics. Of course, Bemmie probably used that too, given that they were even using nanotech for their notepads, but there's no way for me to tell. We'll be able to vary the reflectivity and the geometry to some extent. Much more maneuverable than the base version. So I can say with some confidence that I'll be able to put you on any course you want pretty reasonably quick. We can make our final decisions once we see how she performs."

    Jackie nodded. "Thanks, A.J. I really didn't want to be locked into one course from the start."

    "It wasn't likely, but now it's not a problem. If she works at all. Which I hasten to add she will, Captain."

    Helen saw Jackie wince at the title of address. As the engineer for the drive and the one most familiar with the operation of an actual vessel in deep space, Jackie had ended up with the two "hats" of captain and engineer. Madeline Fathom was willing to be an emergency pilot of sorts, but she refused to take command.

    "On the ground, or in combat itself, perhaps," she'd said. "But you're going to be the one in charge in space, Jackie. A.J. isn't suited to it, and neither is Joe, while neither Helen nor Larry is qualified. Larry can help with the navigation and investigation of anything in the astronomical arena, but he's got minimal technical knowledge. As we can't really take any more people, that leaves us with no other choices."

    "Come on, Jackie," she said. "It's not that bad."

    Jackie shrugged and then gave an unwilling half-smile. "Well, yeah, I guess. If by a miracle this eons-old alien vessel does rise from the dead, I'll be the commanding officer of the fastest ship ever built." The smile widened. "And then I get to prove it by catching the other fastest ship ever built."

    Helen saw the smile widen even more, becoming somehow sharper, and it wasn't a nice smile at all. But then, she'd feel the same in Jackie's position. She almost felt sorry for Horst and Odin.

    Almost.