On the northeast edge of the ma.s.sive area on the surface of Mars called the Mare Hadriac.u.m, stood a complex of domes and cylinders. Made of metal and gla.s.s, it stood on an open plain about 35 degrees south of the equator and 85 degrees east of the central meridian. The complex was one of five atmosphere-generating plants on Mars, and the only one in the southern hemisphere. In a small crater nearby was the settlement of New Emmaus, with a population of about 12,500.

The long process of terraforming Mars had begun when a meteor shower struck the fourth planet in 2009, significantly raising the temperature of the atmosphere and altering the weather systems. With this jump start serendipitously provided by meteorites, Earth had hastened the process of making Mars livable by scattering the surface with spores and seeds, introducing desert-hardy animals, and establishing the five atmosphere-generating plants. Thanks to Earth's efforts, the planet's temperature had continued to rise. Eventually water had emerged from below ground and from the ice caps around the poles, and the air was gradually thickening.

Terraformation had been taking place for almost 150 years, and it would be at least another two centuries before it would be possible to live anywhere on Mars without a s.p.a.cesuit. The atmosphere-generating plants were critical to the process. The plants themselves were automated, with all systems operated and monitored by robots, and the major centers of population on Mars were located in craters not far from each plant. The complexes were on the open surface of the planet rather than in craters, but the air they created flowed first into the nearest depressions in the surface, and it was here that most settlements were located.

The plant located in the southern hemisphere was the most remote, but had been filling the Mare Hadriac.u.m, locally known as the Red Sea, for decades. This great depression was 2,500 miles in diameter. When much of the southern ice cap had melted, it filled the Red Sea with water up to about three-fourths capacity, making the region a delightful place for quiet living.

In the early morning of August 15, 2151, the cloudless sky was a brilliant violet, and the sun was rising like a bowl of molten gold.

Marshal and Averette North, a retired couple, had climbed to the top of the crater wall to enjoy the sunrise. Six miles away was the atmosphere plant, gleaming in the newly-risen sun.

They were the only ones to see what happened next, but it happened so quickly that there was almost nothing to see. In the thin atmosphere, there was only a slight vapor trail and a short-lived but powerful whine; then with a dull, gut-churning thud a ball of black and orange flame slammed obliquely into the desert floor within a quarter of a mile of the atmosphere plant. An enormous wave of pinkish-ochre sand rose up in front of the impact site like a great wall. The shock wave quickly blew the wall of sand upward and outward, so that it sparkled like luminous rain until the sand particles became too scattered to be seen.

The shock wave struck the atmosphere plant and shoved it aside as if a giant, invisible hand were violently clearing a table of unwanted crockery. The crater wall where the Norths were standing rocked and heaved as if in an earthquake. The shock wave pa.s.sed them, blowing their hair and rippling their clothing as if it were a pleasant breeze that died away as quickly as it had come.

The elderly couple stood frozen in shock and watched the cloud of dust gradually fill the entire eastern sky. After several minutes, the dust was thin enough to reveal a horseshoe-shaped crater almost a mile across. On the southwestern edge of the crater, where it trailed off into the desert without a sharp boundary, was the place where the atmosphere plant had been. Now the plant was broken into many thousands of pieces and the wreckage was scattered for three or four miles in a wide fan across the sand.

13: The Brink of Disaster

THE ALIEN s.p.a.cECRAFT was beautifully designed and well equipped. The Starmen had spent more than two days exploring it fully and tracking its electronics systems. It was planned for a crew of twenty. The galley was not stocked, but Zip a.s.signed some of St. George's men to store their food in it. The storage area inside the ship included s.p.a.cesuits for the entire crew. The suits were shaped slightly differently from what the Earthmen were used to. They squeezed a little in the chest and were somewhat baggy between abdomen and knee, especially for the shorter men, but they could be used.

Joe and Mark were working to the point of exhaustion, trying to figure out the controls in the c.o.c.kpit. Mark had to trace innumerable leads from the panel through the walls of the craft back to the wings, tail, and especially the propulsion compartment. The Starmen found the work exhilarating but time-consuming. Mark estimated at the end of the second day that he had figured out about 80% of the control panel, including all the major systems. Joe confirmed his reckoning and, without even igniting the power, was learning to pilot the alien craft.

Both Starmen kept Zip informed of their progress.

It was still up to Zip to find a way to escape from the asteroid. Even if they could pilot the ship, it was certain that the pirates would locate them by radar within seconds of their departure and the chances of their escape would be practically nil.

The atmosphere tanks supplied with the s.p.a.cesuits were empty, so Zip had to fill them from large storage tanks of pure gases he found to one side of the hangar. Since Zip was unable to read any labels, he had to a.n.a.lyze the gas in each supply tank to determine which gases the tanks contained. Once he had succeeded in identifying nitrogen and oxygen, he was able to fill the tanks for the s.p.a.cesuits with a mixture similar to that of air on Earth. This project was tedious and physically demanding, but St. George's men a.s.sisted him with the heavy work. Since the gravity was so low, two men were easily able to move even the largest equipment needed for the work. By the end of the second day, all the tanks had been filled.

That evening, Zip put on one of the s.p.a.cesuits and practiced operating it and moving around inside the hangar. When he was satisfied that the mixture of air was breathable and that he could maneuver in the suit, he took off the helmet and walked over to where Joe and Mark were sprawled under the s.p.a.cecraft with a panel open over their heads. The deep green of the highly reflective metal hull was marvelously soothing to the eye. For a moment, Zip paused and wondered about the race that had built the ships. Then he called out to the others.

"Joe, Mark-I'm going through the airlock to see what's out there."

Joe skidded out from under the hinged panel. "Are you sure that's wise, Zip? We don't know where the pirates are."

"That's why I'm going out. I have a plan for our escape, but I have to explore a little bit outside to see if it'll work."

"Want some company?"

"Thanks, I do, but I'll take George. You and Mark keep up the work."

Zip went over to where George St. George was sitting at a table with several other miners.

"George, could you come with me? I'd like to see what's outside."

"Sure, Zip," said the blond man, standing up. The asteroid miner suited up and the two men walked to the far end of the hangar. Zip was carrying a small iron plate. In front of them was a huge panel that could open to permit s.p.a.cecraft to pa.s.s through the airlock, and on either side of it were sets of doors to allow men through. These doors entered a hallway that proceeded to the outside of the asteroid and allowed pa.s.sage without the major airlock's having to be emptied.

"Ready?" asked Zip through the suits' intercom system.

"Sure. Let's go." Zip opened the door into the airlock and they pa.s.sed through and closed the door behind them. Zip operated the controls that sucked the air out of the hallway. The two men walked about 50 yards to the far end of the pa.s.sage and opened the door to the outside. They stepped out onto the surface of the asteroid.

They looked around, but could see no evidence that there was an airlock adjacent to where they were standing!

"Camouflaged!" said Zip.

"Whoever made this wondrous thing," commented George, "apparently had a reason for wanting to be hidden. Let's make sure we can still get back in. Can you open the door we just came out of?"

"No need to worry. I'm not about to close a door behind me for good until I know I can open it again." He took the small iron plate and used it to jam the door open. From the inside, the door was transparent; from the outside, it looked like the surface of the iron asteroid. Its hinges were completely hidden. "Now let's see what's out here."

For the first time, the two men gazed outward. The Milky Way blazed above and to the right, its countless stars bright enough to cast slight shadows behind the two men.

"I never tire of seeing that view," said George. "I've missed it, just in the few days we've been inside."

"Yes, it's inspiring," answered Zip, but he was already in motion, walking and scanning the ground on both sides of him. George followed.

Their asteroid boots gripped the surface of the asteroid.

"What are you looking for, Zip?"

"Evidence of the pirates. I've got a plan for escaping them, but our exit point here can't be too close to their entrance."

"We've walked a dozen miles through the asteroid from their headquarters-they can't be too close."

"I'm sure you're right, but there may be other entrances. We found one, didn't we?"

"Even if there were other entrances, they're bound to be as invisible to the eye as the one we just came out of."

"Right again, I'm sure, George, but I don't want to take any chances.

Our escape depends on our being unseen-at least for most of the time.

Then I want to be seen."

"What do you mean, Zip? I- " George suddenly stopped talking, almost as if his communicator had been turned off. Zip looked over.

"What's wrong, George?" Through his helmet, George's eyes were opened wide and his mouth was agape. "What is it?" Zip repeated.

"We, we, we're not in the Asteroid Belt," George stammered. "Look, there's the Belt over there." He raised his hand and pointed. The slow rotation of the asteroid that gave it its slight gravity had brought the Belt into view over the horizon. Motionless on the asteroid's surface, Zip and George were slowly moving into the dawn. A pale sun far away was coming into view, and a golden line of light began to grow over the 45-mile-long chunk of almost pure iron. The s.p.a.cesuits'

faceplates automatically darkened slightly. The sunlight came through a scattering of asteroids...o...b..ting at least a thousand miles away.

"He's moved the asteroid. He knows more about it than I gave him credit for," Zip said grimly. "My plan will still work, but the situation has changed. Now we have to hurry. Let's go back."

Back inside the hangar, Zip called a meeting of the fourteen men and explained his plan for escape.

"Sounds good, Zip," affirmed Mark, and Joe agreed.

"What about food and water?" asked one of the miners.

"What's left?" responded Zip. "How many days can we go if we ration even more strictly?"

"About five until the food runs out, and there's about a gallon of water for each man left."

"We can do it. No choice anyway. Let's get some sleep and start things rolling first thing tomorrow."