"Plastics," said Gordon. "They can be shredded and remolded. Could always use more."

Alex shook his head. "Plastics would be too bulky to lift in useful quantities. We need things that are small and valuable."

"Don't rule anything out, yet," said Sherrine. "We're brainstorming."

"Too bad you can't grow plastic from seeds," said Doe. "Like you can plants."

"But you can!" Mike said suddenly.

"What?"

"Well, not quite; but… There was an experimental field--in Iowa?--where they grew plastic corn. Alcaligeneseutrophus is a bacterium that produces a brittle polymer. Eighty percent of its dry weight is a naturally grown plastic: PHB, poly-beta-hydroxybutyrate…"

"Contains only natural ingredients!" declared Steve with a grin.

"Researchers found they could coax the bug into producing a more flexible plastic by adding a few organic acids to the glucose 'soup.' They cloned the polymer producing enzymes--oh, 1987 or so--and spliced them into E. coli. Later, they spliced them into turnips, and finally corn. That was the bonanza. The mother lode of plastic. The corn grew plastic kernels. Think of it: plastic corn on the cob," he chuckled. "Shuck the cobs and you get pellets. Perfect for melting in a forming machine hopper."

Doc frowned. "And you plant some of the plastic seed corn and grow more? That doesn't sound right."

Mike shook his head. "No, that was the problem, plastic seeds don't germinate. So you'd still need the original bugs, but you can breed them in vats and harvest the polymers directly Not as efficient as the corn, but… They were this close to cracking the sterility problem when the National Scientific Research Advisory Board halted all testing."

"It sounds fantastic," said Alex. "Where can you find this bug?"

"A. eutrophus? In the hold of the Flying Dutchman. It's just a story that agents pass around. The test plot was abandoned when genetic engineering "was outlawed. Later, it was burned by a Green hit squad."

Doc grunted. "Hunh. Burning plastic corn? I'll bet it released a toxic smoke cloud."

"Sure. But that was the fault of the scientists, not the arsonists. They burned one of the scientists, too."

"My grandmother would know," said Sherrine.

Heads turned.

"My grandmother. She's a genetic engineer, remember? If anyone knows where we could lay hands on a culture of this A. eutrophus, she would."

Alex felt a tingle in his limbs. They weren't just joking around any more. They could make it work. Foodstuff. Seeds. Vitamins. Spices. Plasi-facient bacteria, for crying out loud! They could actually make it happen. They knew where to find the stuff. Or they knew people who knew. He glanced at Gordon, who was looking straight at him, reading the hope in his eyes.

Sure. Make the payload valuable enough and Lonny Hopkins himself would fly out and grab it, Alex MacLeod and all.

"How would you handle meat, though?" asked Doc. "No seeds. No pills."

"Small animals. Rabbits. They breed fast and they're relatively meaty for their size."

"Guinea pigs? The Incas used those."

"Chickens."

"Hold it. Hold it. This rocket is starting to sound like a Central American bus."

"Forget the chickens," said Mike. "Take fertilized eggs. They take up less space. Hatch 'em in an incubator. Use the hens for egg production. Keep a rooster or two for breeding stock and use the rest for meat."

"But we don't have a chicken incubator," said Gordon.

"Build one. We can put the design and operating manual on a disc."

"Hell's bells," interjected Doc. "Give 'em a whole library on disc. SF, too, of course. They must be getting tired of reading the same books over and over. As for the rabbits and guinea pigs, just take the germ plasm. You have a sperm bank, don't you?"

"Well, uh, yes. For humans."

"Good. Frozen sperm, then. Frozen ova, too. Mix 'em in vitro. Though you'll still want to take a few females along, just in case. Ova are more delicate than sperm."

"Is diversity problem in sperm bank," said Gordon thoughtfully. "Gene pool is limited."

"Mars Needs Women!" shouted Mike. Sherrine looked up from her notepad and blushed a deep crimson. Before she could say anything, Bruce Hyde spoke from the doorway.

"Do I want to know what this discussion is about?"

Sherrine and the others told him, all talking at once. He looked at Alex. "Will it work?"

Alex shrugged. "Why fly an empty truck? As long as we have enough fuel to lift the mass." And that would be a pretty problem! Trading altitude for cargo. There had to enough cargo to make a rendezvous cost-effective. The more, the better. But more cargo, less altitude; and Lonny would have to use more fuel to match orbits, and… Where was the break-even point? It was a question of minimizing the rendezvous costs while maximizing the cargo value. A minimax problem. But it wouldn't do any good to try and calculate an answer. Too many indeterminates--Lonny would be making his own decisions anyway.

"Alex?" Steve was waving a hand at him.

"I'm sorry. What did you say?"

"I asked about spare parts and fittings," said Steve.

"We can fabricate most of what we need," Alex told him, "if we have the materials and the machine tools." Maintenance was the one activity in the habitats that was absolutely crucial. "We can scavenge and salvage most materials, although we're always short and more would always be welcome; but machine tools and dies for the machine shop are essential. Some of our blades and drill bits and molds have been reground or resharpened until they're useless."

"Machine tools would be small," said Mike, "but heavy."

"No critiques, yet," Sherrine reminded him as she wrote. "What else?"

"Surgical implements," said Doc. "I'm sure people up there still suffer injury and illness." He shuddered. "I'm trying to imagine resharpened scalpels and hypodermics."

Alex nodded. "You're right. I'd forgotten. Shots hurt."

"And medicines," continued Doc. "All sorts. You must have to ration what medicines you have mighty close."

Doc might as well have pierced him with one of his scalpels. Rationing… In a society of scarcity there was always rationing; and some people were on top of the rationing list and others were at the bottom. If Lonny or Mary or hydroponics chief Ginjer Hu fell sick, there would be medicine available. "Essential personnel." If Alex MacLeod fell sick…

And if he did climb back into orbit with a rocketful of goodies, would his name move up the list? More to the point, how much could they realistically take with them in a Titan, anyway? Brooding, Alex dropped out of the brainstorming session.

"Not only medicines," said Sherrine, "but other chemicals, too. 3MJ has chlorine for his pool right here. He might let us have some."

"Metals, too," said Gordon "… Nah. Too heavy. We would not lift enough metal to matter."

Bruce laughed. "What do you suppose the Titan is made of? If we can loft it hard enough, we can put the booster into a recoverable orbit. Then your people can mine it to their heart's content."

Later, when they were alone for a few minutes, Gordon looked at him with widened eyes. "It cannot work, but they believe--do you believe, too?"

Alex arranged the blanket around his legs. He smoothed the green paid cloth, tucking the folds out of sight. Experimentally, he pulled on the chair's wheels and was pleased to see that he could roll himself across the room. As Doc had told him, the upper body strength would come first. It was the muscles needed for standing and walking that needed the training. That and replenishing the bone calcium. He looked at Gordon.

"I think it could work. The essence of trade is 'Cheap here; dear there.' Make the cargo valuable enough and get the rocket close enough and, yes, it damn well could work." Gordon's blanket was a dull monochrome, which secretly pleased Alex.