The third member of the crew stood by the far wall of the ship, looking through the port at the irregular pitted mass of rock that was looming gradually closer to the Alberich. She was rubbing at the back of her head, thinking hard. “I don’t know, Alexis. There’s an ample margin on the volatiles, we can get it there easily enough. But can we do it quickly enough? The Probit group is offering a ten percent bonus for the next hundred million tons of nickel-iron in Earth orbit.”
Galley nodded. “They’re fighting deadlines.”
“As usual,” said Lubin. “And so are we. I’m afraid that Pincus and his team will beat us to it. I’ve been listening to their radio broadcasts and they’ll be starting to move their choice in another day or two. Even if we decide this minute, we won’t have the drives on this rock for close to a week, and we won’t pick up any time on them in the transfer orbit. If anything, they’re better placed for transfer than we are.”
“Then we’re in trouble.” Alexis Galley peered vacantly at the screen. “Getting there second would halve our profit. Maybe we should look some more, try and find one with a better composition.”
“We shouldn’t do that.” Regulo had been listening intently to the exchange. Alexis Galley was always too conservative, and Regulo needed that bonus far more than either Galley or Nita Lubin. “We’ve taken weeks to find one as good as this. How about trying a hyperbolic?”
There was a silence from the other two.
“There should be plenty of reaction mass for it,” Regulo went on. “You said yourself that there were ample volatiles, Nita — and we’d pick up at least four weeks on total transit time.”
Galley looked up at Regulo’s thin face and pale, bright eyes. “I think you know my views on hyperbolic transfers,” he said. “Do I have to say them again? You’ll boil off some of the volatiles and lose reaction mass on solar swing-by. If you’re unlucky you’ll find that you have to ask for help when you’re past perihelion, just to get yourself slowed down into Earth orbit. You can spend twice your profits on tugs to help you in. Still” — he shrugged — “I don’t like to close my mind to things, just because I’m getting older. How close in would we have to go?”
“Three million kilometers, at perihelion.”
“From the center of the Sun, or from the surface?”
“From the center.”
“Hell. We’d only be two and a quarter million from the solar surface. That’s close, too close.”
“But we won’t be there for long,” Nita Lubin broke in. She came forward and stood by the screen. “I think we should do it. We’ve talked about it before, and we always find a reason not to. Let’s try it. We don’t have to stay with the rock, you know. We can separate ourselves on board the Alberich once we get in as far as Mercury, fly on an orbit with a bigger perihelion distance, and re-connect with the rock later.”
“But then we’ll be too late to meet it,” protested Galley. “If we fly past further out, we’ll take longer.”
“Not if we take the Alberich on a powered fly-by. Alexis, you’re just making up reasons to avoid trying.” Nita Lubin seemed to have made up her mind. She turned to their junior crew member. “How long will it take you to work out a decent power trajectory for the Alberich? We’ll need to have a few choices.”
Regulo did not speak. He reached into his pocket, produced an output sheet and held it out to her.
“What’s this?” Nita Lubin glanced quickly over the sheet, grinned, and placed it in front of Galley. “Orbits for the Alberich. He’s really hungry, isn’t he? Well, there’s nothing wrong with that — it’s what we’re all here for. What do you think, Alexis? We’d have a twelve-million-kilometer perihelion for the ship. That’s not too bad, though I suppose I’d better check it for myself. You two might as well get to work putting the drives out on the rock. We should have plenty of time for that if we can really pick up four weeks on the transfer, the way this analysis shows.”
Alexis Galley stood up slowly from the console and looked for a long moment at the other two. “I still don’t like it, but I’ll go along with it. You put up most of the money, Nita, and it’s only right that we try and protect your investment. Remember one thing, though. Neither of you has ever done any work close in to the Sun. I have. We’re going to find that timing is tighter there — you don’t have as much margin for error as we have out here. If you don’t mind, Nita, I’ll check those calculations when you’ve done with them.”
He left the cabin and went forward towards the drive supplies and installation facility. Nita Lubin looked after him thoughtfully. “You know, he’s only going along with this for me, Darius. I’m wondering if we ought to go through with it. Alexis has more experience than the two of us put together.”
Regulo stared at her, his head cocked to one side. “What do you mean, Nita? I thought it was all settled. Look, I don’t know about you but I certainly don’t want to lose to the Pincus group. That’s what will happen if we settle for the usual elliptic orbit transfer. We’ll lose, there’s no question of it.”
His face had gone pale, and his eyes blazed. Nita Lubin looked at him shrewdly. “You are hungry, Darius — more than I ever realized. Well, I still say that’s no bad thing. I’m in this for profit myself, and so is Alexis. You go up front and help him, and let me check your calculations.”
“They’ll be right,” said Regulo. He turned quickly and left the cabin, before Nita Lubin could speak further.
The first stages of the orbit transfer were following the classical pattern that Alexis Galley had pioneered more than twenty years earlier. First the shape of the asteroid was mapped and recorded from multiple angle images. Next came the detailed mass distribution calculated from analysis of seismic data. That determined the place where powerful explosive pellets would be sited in bore holes drilled deep into the rock. Even with these they would gain only an approximate distribution of the internal densities, but that was still their best source of information on the amounts of ammonia, solid carbon dioxide, water and methane ice inside the asteroid — the source of the reaction mass that would power the transfer of the fragment to Earth orbit.
Galley and Regulo were at the computer, working together on the computation of the drive placings. As volatiles were consumed and expelled in flight, the center of mass and moments of inertia of the remaining rock would change. The drive thrust had to remain exactly through the changing center of mass, or the whole planetoid would begin to rotate under the applied torque.
“See now why I’m against your damned hyperbolic fly-by?” grumbled Galley. “When you send anything that close to the Sun, the boil-off rate goes crazy. You lose a good fraction of your volatiles in just a few hours if you go in near enough. That’s going to ruin the center-of-mass calculation. We never run into that sort of problem with an elliptic transfer, but now we have to think about it.”
“We can allow for it,” said Regulo. His voice was confident. “It’s just a matter of a little more calculation. I’ll work out the solar flux as a function of our time in orbit, and that will give us all the boil-off information that we need.”
“Oh, I’m not saying we can’t do it.” Alexis Galley shook his head. “Only that it’s a pain, and we’ll lose another day while we’re at it.”
“Look, I’m not asking you to do it. I’ll be quite happy to handle all the computation.”
The older man looked at Regulo calmly. “Now then, Darius, just cool off. I’m not saying you don’t take your share of the work, and more. I’m just saying that I still don’t care for this whole thing. I’ve only flown one hyperbolic in my whole life, and that was in an emergency medical ship with unlimited thrust. We weren’t trying to steer a billion tons of rock along with us, either. This is a tricky business, one you don’t jump into without a decent amount of thought. If you’re going to work on the calculations, I’ll go out on the rock and take another look at the position of the drive placings.”