Bigfoot gave him a thumbs-up. In the waiting area, they opened the doors and the passengers started up the boarding ramp.

On board, they ran quickly through their preliminary checkoff. Tony reported he was ready to go, and Bigfoot showed up on the circuit again.

"Don't you ever sleep?" asked Tony.

"Not lately. And neither will you. When you download your schedule you'll notice that you're going to be flying continuously between now and impact. Try to divvy up duties where you can. Sleep when the opportunity offers. Tony, I have to tell you, we'll get everybody out, but it'll be close, and it'll only happen if everything goes like clockwork." He paused. "You're cleared to depart."

Saber had gone below to make sure the passengers were ready. They were still hauling families and visiting VIPs. She reported everything secure in the cabin and hurried back up the ladder while Tony got his final countdown. Overhead, the roof divided and rolled back.

"They're really excited," said Saber. "Especially the kids."

"About getting away?"

"About riding on the Percival Lowell."

He lifted away from Moonbase. It was a near-perfect launch, requiring only a few brief bursts from the attitude jets, not enough to reveal that one was firing rich, using twice the amount of fuel as the other eleven. He felt relieved when the main engine shut down with no telltales or warnings on his board, and no suggestion that fuel usage had risen. Maybe they had failed to fill his tanks; or maybe it had been a computer glitch.

Once they were in orbit, Tony went down to say hello to his passengers. He always made it a point to visit the cabin.

Usually, during the five-plus hours between L1 and the Moon, he did it at his leisure, welcoming people aboard, lending his calm demeanor to the inevitable one or two who were making their first flight. He wore grip shoes even though he'd long since learned to move with ease through zero-g. Those who might already be a little skittish reacted more positively to a captain who seemed to have his feet planted firmly on the deck.

The VIPs were seventy-year-old Kwae Li Pak, listed as a world-renowned expert in long-term low-gravity effects on musculature; a United States senator; a nineteen-year-old student from the Polytechnical University of Catalunya, whose trip to the Moon had been first prize for a science project; and a Russian industrialist.

All were excited, even Pak. The senator, who was from South Carolina, wished aloud that the hand of God would reach out and strike the comet down. He seemed to be in much of Tony's state of mind. The Russian made it a point to thank Tony and to inquire when the pilot himself would get clear.

"I'm not sure," he answered. And after a moment's thought: "As soon as I can."

Lowell showed up on the scopes right on schedule. Tony put a visual on the overhead and Saber gazed at it admiringly. "It's the only way to travel," she said.

Tony shrugged.

The first time Tony had seen the Lowell, docked at L1, he'd felt mixed emotions. Great-looking ship, all dressed up with nowhere to go. Mars was just a desert with a big volcano and some very old riverbeds. Hardly worth two years on plastic rations.

The Micro closed gradually with the interplanetary vessel. Tony exchanged operational data with a female voice.

"That'll be Rachel Quinn," smiled Saber. There was something forlorn in her tone.

"You wouldn't really want to make that trip, would you?" he asked.

Saber smiled. "I'd kill," she said.

Lowell's docking port was located on its underside in the after section. Tony swung the Micro into position, setting it almost crosswise with the larger ship, and handed control over to the autopilot, which took it across the last fifty meters. He switched on the intercom and warned the passengers not to remove their harnesses until they were advised to do so. A light jarring underscored the admonition.

But the magnetics had taken hold and amber lights were coming on, signifying that the connecting chamber between the docking grips was sealed and beginning to pressurize. Minutes later the lights went green, and Saber went below to stand by the airlock.

Tony heard the hatches open, heard Saber talking with another woman, who must have been Rachel Quinn. Then he slipped out of his own seat and went below to say good-bye to his passengers.

They filed out happily, and he heard cries of delight as they arrived on board Lowell. Then he caught a glimpse of Quinn.

"See you at Skyport," she said. And the hatch at the other end closed.

Tony was mildly irritated. It was true the Micro didn't have much glamor, but it was a tough little workhorse, and these people weren't treating it with proper respect.

"Damn," said Saber.

"I know what you mean," said Tony.

"I wanted to climb through and get a look."

"Oh. Well, you saw it at L1. Hell, you've been inside it a half-dozen times."

"It's different out here," she said. "It's alive now."

"I don't think we have time to spare," he said.

"I know." She keyed the disconnect and watched their own hatch close.

He used the thrusters only twice during the withdrawal. SSTO Berlin Flight Deck. 7:12 A.M.

The faulty navigational programming created a problem for all three space planes. Berlin's pilot, Willem Stephan, was placidly watching Moon and comet growing larger when the alert came in from Moonbase: "We show Berlin and Copenhagen off course."

"Negative," his flight engineer told him. "Flight profile looks good."

"Moonbase," Stephan said, "we do not show variance." Copenhagen, eighty kilometers off to starboard, was a bright star.

"Wait one," said Moonbase.

Stephan switched over to Nora Ehrlich in Copenhagen, "How do you look?"

"Same as you, Willem. Right on target."

The voice came back: "Both birds, this is Moonbase. We want you to go to manual. Switch to Channel Eleven and pick up the beacon. Acknowledge when you've complied."

His flight engineer was Gruder Muller, a friend who went all the way back to his University of Hamburg days. Gruder brought the beacon trace up on the screen. "Berlin acknowledges," said Stephan.

"Roger. Stand by for course correction."

"Roger, Moonbase." He exchanged glances with Gruder. Maybe piloting between Earth and the Moon wasn't quite the exact science he'd thought.

"Berlin, this is Moonbase." A new voice. With authority. Probably the watch supervisor. "We are going to slot you into a different vector from the one planned. We think there's a glitch in the programming, so we'll do the rest of this hands-on. Do you read?"

Stephan acknowledged.

He entered the new data into the computer, and six minutes later executed his course change. Copenhagen followed suit.

Berlins first scheduled pickup was to be from the microbus. He ran a simulation of the rendezvous. "We don't match up so well now," he said. "The Micro's going to have to finagle a bit." Washington, D.C. 7:22 A.M.

Harold Boatmann hadn't slept all night. The gray dawn was seeping through the curtains of his Georgetown apartment. He gave up and got out of bed, scrambled some eggs, put a half-dozen strips of bacon into the microwave, made a pot of coffee, and checked with his duty officer. Things were calming down a bit. People had been soothed by White House assurances and by the tack adopted by the media, which were downplaying the comet and portraying those who took to the roads as cranks.

The transportation secretary should have been gratified. But the truth was that the administration's position was a gamble. Tens of thousands of lives might be lost if they guessed wrong. Boatmann wondered how he would live with that kind of burden.

He picked at his breakfast and finally gave up on it, taking his coffee into the living room, where he sank into an upholstered chair. He propped his feet on a hassock, set the cup down on a side table, and stared at the row of framed photos on the mantel. The room was still dark, the shades drawn against the morning light, the photos hidden in shadow. They were his son and daughter and a bevy of grandchildren, in-laws and cousins, friends from earlier days now scattered around the country. And a photograph of himself and Margaret and the president, taken on the White House lawn during a signing ceremony. His thoughts kept returning to yesterday's White House meeting.