“What about putting something out in space?” Jessie was young, but she could be dogged when she had an idea in her head. “Couldn’t a superconducting mesh average the field?”
“It could.” Davis raised his eyebrows. “Have to be twenty thousand kilometers across, mind you, and thirty thousand kilometers out beyond Cusp Station. We could make something like that — if we had a few years. How long did you say we have, John?”
“Twenty-six days before the main hit. But Amanda and Jessie have the right idea. Keep thinking.”
Advice easier to give than to follow. In the long silence that followed, John glanced from one perplexed face to the next. He was asking his engineering team for a miracle.
The person who eventually spoke was not one of his team. Star Vjansander had been nudging Wilmer Oldfield, muttering to him, and blowing out her round cheeks. Now she frowned at Wilmer and said, “What was it that feller Colombo said in our first meeting out here, about Missus Hommit going ter see a mountain?”
It was blank stares all round, until Wilmer said mildly, “Not Ma Hommit, you softheaded git. Mahomet.”
“Yeah, that one. I’m rotten with names. If the mountain wouldn’t go to Mahomet, he’d have to go ter the mountain.” She nodded to John, as though confirming something he had said. “So that’s what yer have to do.”
“Star, you’re jumping so far ahead you’re falling all over yourself. You always do.” Wilmer turned to Will Davis. “How close to finished was the old shield?”
“Ninety percent plus. All the structure and stability was done, but we were still missing batches of sensors.” Davis shook his head. “Seven years of my life in that bloody thing, and it’s useless. Ah, well. Easy come, easy—”
“Don’t give up on it.” Wilmer went on, slowly and thoughtfully. “It’s useless as a shield, but it’s covered with a superconducting mesh. That’s what was going to divert the particles when we thought they were coming in as single nuclei. The mesh isn’t enough to deal with the bundles, they’re too massive. But could it do what Jessie said, and average the detection field that we create?”
It was like the promise of reinforcements to a tired army. John saw the engineers straighten up in their seats. “Can it, Will?”
“It could, very easily. But the shield is in the wrong place. To average the detection field, the shield would have to move thirty thousand kilometers farther out. That’s not impossible, but the structure is so fragile and so finely balanced that the operation would take a few months. We don’t have months. We have just a few weeks.”
“I know.” Star was bobbing up and down in her chair. “I know. That’s why I said what I did. Yer don’t take the mountain ter what’s-’is-name, you leave the mountain where it is.”
“Shut up, Star. You’ll give people headaches.” Wilmer reached out and pushed her back into her seat. “Just keep quiet, and let me explain your idea.”
“I’ve heard you explain things before. Yer’ll bore ’em to death, you old fart.”
Wilmer took no notice. He went on in his unhurried way, “She’s bright, you see, but when she gets excited she gibbers like a monkey. Here is the position, as I understand it. The old space shield is no use as a shield anymore, because it’s far too fragile to divert the high-mass particle bundles. However, it would serve perfectly to average the low-intensity field that detects those bundles. Unfortunately, it is in the wrong place relative to Cusp Station, where you have installed the generators for high-energy pulses that can divert particle bundles away from Earth. To serve that purpose, the shield would have to be moved thirty thousand kilometers away from Cusp Station, in the direction of Alpha Centauri, since that is where the particle storm is coming from. However, the shield is so delicate that such movement would have to be done very slowly, at minuscule acceleration. It therefore appears that we have reached a solution too late. The particle storm will be here before the shield can be relocated.
“We would appear to be faced with an insoluble problem. That, however, is an illusion. The fragile shield cannot be moved in time. But why not, as Star suggests, invert the problem? We do not care about absolute position, we care only about relative position. Rather than moving the shield thirty thousand kilometers toward Alpha Centauri, Cusp Station must move thirty thousand kilometers away from Alpha Centauri — closer to Earth.” Wilmer turned to John. “One question remains, which I regard as an engineering detail: Is Cusp Station strong enough to withstand the necessary acceleration?”
“If a group of you physicists wanted to land on the surface of the Sun and do experiments, you’d say the design of the ship that takes you there and back was engineering details.” John was cursing — at himself. He was sure that the rest of his team was feeling the same way. To miss an obvious possible solution, and have it pointed out by a pair of physicists, who sat with their heads in the clouds . . . He went on, “Cusp Station has to be strong enough. We fly it inward even if it falls apart on the way. And we must change the trajectory of this place, too, so Sky City finishes next to Cusp Station’s new location and we can fast-link the computers. Amanda?”
“A few hours’ calculation.” She rolled her head from side to side, as though she was attempting the calculation mentally. “If thirty thousand is a good working number for the move toward Earth, I’ll have you a flight profile for Cusp Station and a modified one for Sky City by this evening.”
“Will?”
“Cusp Station was built rugged. I’ll be out there anyway, installing the field loop generators. Say, one day to decide where the mirror-matter thrustors go, two days to attach. Three days from now we’ll be ready to move.”
“Torrance? How about Sky City?”
“We’re running close to maximum stresses in some places already. What are you looking for?”
“Too soon to tell. Aim for a factor of two.”
“Christ. We may fall apart.”
“If this works, we’ll have plenty of time for repairs. If not, we won’t need ’em. Lauren, you know the interior structure of Sky City better than anyone. I rely on you to pick out the weakest spots and be ready to strengthen them.” John glanced again around the group. He saw new energy on every face. “Anything else? I know there are a thousand details to be discussed and worked through, but I don’t want to take the time of the whole group on every one.”
Lauren Stansfield said, “A question that’s not engineering. When do we tell other people about this?”
“As soon as anyone asks. Just don’t waste time on long explanations. From the point of view of most people, nothing has changed. The old shield can’t handle the particle bundles, we’re building a new particle defense system, and it’s touch and go. That’s all still true — the job just became more difficult.”
“No.” Will Davis stood up. “An hour ago it was impossible. Now there’s hope, so it must be easier. Good one, Star.”
He left, and the others wandered out after him. Star Vjansander went reluctantly, saying, “It was my idea. I oughter stay and help.”
“It was your idea.” Wilmer shepherded her out. “And you ought to go. Anything you touch, you smash.”
Finally it was just John and Maddy Wheatstone. She came right up to him. “You know I’m not a trained engineer. But I’ll do anything I can to help.”
John asked the question he had been putting off for over a week. “Don’t you have to go back to Earth? I’m sure the Argos Group has other assignments for you now.”
“I don’t work for the Argos Group anymore. I quit.”
“You resigned? Why?” He saw the tormented expression in her eyes. “I’m sorry, I know that’s none of my business.”
“It’s all right. I resigned because of — personal reasons.”
“I see.” But he didn’t.
She seemed wilted, as though someone had sucked all the life out of her, as she said, “If you don’t mind, I don’t want to talk about it now.”