Falling Free

Ice.

Leo watched from the sealed control booth overlooking the Habitat freight bay as four worksuited quaddies eased the intact vortex mirror taken from the D-620’s second Necklin rod through the hatch from Outside. The mirror was an awkward object to handle, in effect an enormous shallow titanium funnel, three meters in diameter and a centimeter thick at its broad lip, mathematically curved and thickening to about two centimeters at the central, closed dip. A lovely curve, but definitely non-standard, a fact Leo’s re-fabrication ploy must needs cope with.

The undamaged mirror was jockeyed into place, nested into a squiggle of freezer coils. The spacesuited quaddies exited. From the control booth, Leo sealed the Outside hatch and set the air to pump back into the loading bay. In his anxiety Leo literally popped out of the control booth, with a whoosh of air from the remaining pressure differential, and had to work his jaw to clear his ears.

The only freezer coils big enough to be adequate to the task had been found by Bobbi in a moment of inspiration, once more in Nutrition. The quaddie girl running the department had moaned when she saw Leo and his work gang approach again. They had ruthlessly ripped the guts out of her biggest freezer compartment and carried them off to their work space, in the largest available docking module now installed as part of the D-620. Less than a quarter of the final Habitat re-assembly was left to go, Leo estimated, despite the fact that he’d pulled a dozen of the best workers onto this project.

In a few minutes three of his quaddies joined Leo in the freight bay. Leo checked them over. They were bundled up in extra T-shirts and shorts and long-sleeved coveralls left by the evicted downsiders, with the legs wrapped tight to their lower arms and secured by elastic bands. They had scrounged enough gloves to go around; good, Leo had been worried about frostbite with all those exposed fingers. His breath smoked in the chilled air.

“All right, Pramod, we’re ready to roll. Bring up the water hoses.”

Pramod unrolled several lengths of tubing and gave them to the waiting quaddies; another quaddie ran a final check of their connections to the nearest water spigot. Leo switched on the freezer coils and took a hose.

“All right, kids, watch me and I’ll show you the trick of it. You must bleed the water slowly onto the cold surfaces, avoiding splash into the air; at the same time you must keep it going constantly enough so that your hoses don’t freeze up. If you feel your fingers going numb, take a short break in the next chamber. We don’t need any injuries out of this.”

Leo turned to the backside of the vortex mirror, nestled among but not touching the freezer coils. The mirror had been in the shade for the last several hours Outside, and was good and cold now. He thumbed his valve and let a silvery blob of water flow onto the mirror’s surface. It spread out in swift feathers of ice. He tried some drops on the coils; they froze even faster.

“All right, just like that. Start building up the ice mold around the mirror. Make it as solid as you can, no air pockets. Don’t forget to place the little tube to let the air evacuate from the die chamber, later.”

“How thick should it be?” asked Pramod, following suit with his hose and watching in fascination as the ice formed.

“At least one meter. At a minimum the mass of the ice must be equal to the mass of the metal. Since we’ve only got one shot at this, we’ll go for at least twice the mass of the metal. We aren’t going to be able to recover any of this water, unfortunately. I want to double-check our water reserves, because two meters thick would certainly be better, if we can spare it.”

“However did you think of this?” asked Pramod in an awed tone.

Leo snorted, as he realized Pramod had the impression that he was making this entire engineering procedure up out of his head in the heat of the moment. “I didn’t invent it. I read about it. It’s an old method they used to use for preliminary test designs, before fractal theory was perfected and computer simulations improved to today’s standards.”

“Oh.” Pramod sounded rather disappointed.

Leo grinned. “If you ever have to make a choice between learning and inspiration, boy, choose learning. It works more of the time.”

I hope. Critically, Leo drew back and watched his quaddies work. Pramod had two hoses, one in each set of hands, and was rapidly alternating between them, blob after blob of water flowing onto the coils and the mirror, the ice already starting to thicken visibly. So far he hadn’t lost a drop. Leo heaved a weary sigh of relief; it seemed he could safely delegate this part of the task. He gave Pramod a high sign, and left the bay to pursue a part of the job he dared not delegate to anyone else.

Leo got lost twice, threading his way through the Habitat to Toxic Stores, and he’d designed the reconfiguration himself. It was no wonder he passed so many bewildered-looking quaddies on the way. Everyone seemed frantically busy; on the principle of misery-loves-company, Leo could only approve.

Toxic Stores was a chill module sharing no connections whatsoever with the rest of the Habitat but a triple-chambered and always-closed airlock of thick steel. Leo entered to meet one of his own welding and joining gang quaddies still assigned to Habitat reconfiguration on his way out.

“How’s it going, Agba?” Leo asked him.

“Pretty good.” Agba looked tired. His tan face and skin were marked with red lines, telltales of recent and prolonged time in his worksuit. “Those stupid frozen clamps were really slowing us up, but we’re just about to the end of them. How’s your thing going?”

“All right so far. I came in to prepare the explosive, we’re that far along. Do you remember where the devil in all this—” the module’s curved walls were packed with supplies, “we keep the slurry explosive?”

“It was over there,” Agba pointed.

“Good—” Leo’s stomach shrank suddenly. “What do you mean, was?” He only means it’s been moved, Leo suggested hopefully to himself.

“Well, we’ve been using it up at a pretty good clip, blowing open clamps.”

“Blowing them open? I thought you were cutting them off.”

“We were, but then Tabbi figured out how to pack a small charge that cracked them apart on the line of the vacuum fuse. About half the time they’re reusable. The other half they’re no more ruined than if we’d cut “em.” Agba looked quite proud of himself.

“You haven’t used it all for that, surely!”

“Well, there was a little spillage. Outside, of course,” Agba, misapprehending, added in response to Leo’s horrified look. He held out a sealed half-liter flask to Leo’s inspection. “This is the last of it. I figure it will just about finish the job.”

“Nng!” Leo’s snatching hands closed around the bottle and clutched it to his stomach like a man smothering a grenade. “I need that! I have to have it!” I have to have ten times that much! his thought howled silently.

“Oh,” said Agba. “Sorry.” He gave Leo a look of limpid innocence. “Does this mean we have to go back to cutting clamps?”

“Yes,” squeaked Leo. “Go,” he added. Yes, before he exploded himself.

Agba, with an uncertain smile, ducked back out the airlock. It sealed, leaving Leo alone a moment to hyperventilate in peace.

Think, man, think, Leo told himself. Don’t panic. There was something, some elusive fact or factor in the back of his mind, trying to tell him this wasn’t the end, but he could not at present recall… Unfortunately, a careful mental review of his calculations, keeping track on his fingers (oh, to be a quaddie!) only confirmed his initial fear.

The explosive fabrication of the titanium blank into the complex shape of the vortex mirror required, besides an assortment of spacers, rings, and clamps, three main parts; the ice die, the metal blank, and the explosive to marry the two. Shotgun wedding indeed. And what is the most important leg of a three-legged stool? The one that is missing, of course. And he’d thought the slurry explosive was going to be the easy part…

Forlorn, Leo began systematically going around the Toxic Stores module, checking its contents. An extra flask of slurry explosive might have been misplaced somewhere. Alas, the quaddies were