This news was passed back to Feinberg, who was at that moment landing at Hartsfield.

He'd been keeping abreast of the varying fortunes regarding the SSTOs. Last night, when one of the planes had been destroyed trying to return from Skyport, he'd been informed that they were down to six, and that he'd have to find a way to make do. When he'd explained to Orly Carpenter at NASA that it simply wasn't possible, they'd found another one someplace.

Damned bureaucrats. Playing their games even when the life of the world was at stake.

Carpenter was waiting for him when he landed. The imaging data from Lowell had arrived and they retreated to a virtual tank to begin picking landing sites. Feinberg stared at the Possum, tumbling, rotating around its long axis once every fifty-three minutes and eleven seconds.

He was, in a way, gratified. His life had been devoted to the quiet collection of knowledge that should have had no practical value. Yet here he was, able to engage his specialty to save the United States of America, for God's sake, and maybe civilization itself. Not bad for an astrophysicist. It would be a rousing climax to a life lived, despite his awards, in relative obscurity. Knowledge was its own justification, of course. To discern how the solar engine worked, why galaxies formed, how long a given star could be expected to live. These kinds of issues were the proper pursuit of humanity. No matter that they might not provide a blueprint for how to build a better house or make the economy behave. (The issue of practical applications had driven him to fury last year when yet another effort to fund the supercollider had failed. The Congress had asked what benefit could be derived from understanding how creation had happened; and the physicists, to their eternal discredit, had no answer.)

Still, it felt good to apply his knowledge. To know that, because the astronomers had been here, this civilization would live.

"Here," he said, illuminating a point toward the rear, high in the Back Country. "And here." Toward the front of the Plain. "The real problem is that a lot of the ground's just too rough. They wouldn't be able to get close enough to lock the planes down. And in some places, the lava base is too weak. But we can make do." Eventually they agreed on the seven sites.

TRANSGLOBAL SPECIAL REPORT. 7:20 A.M.

"This is Shannon Gardner in downtown St. Louis. I'm only a few miles from where it all started, in Valley Park, one week ago today when a young woman spotted a comet during a solar eclipse. Since that momentous afternoon, countless people have died, the nations of the world have been ravaged, there are trillions of dollars in property damage, and the worst threat of all still hangs over our heads. In the background, you can see looters. There are few police left here now to stop them. With less than twenty-four hours to go before the Possum is scheduled to impact in Kansas, everyone who can get out of the city has done so, and the only ones left are those who have no money, or no hope.

"The buses that were brought in by the city, and by various civic organizations, are gone now. The highways around this abandoned metropolis are locked tight with dead vehicles. The only way in or out is by air. Or on foot. We'll be abandoning our sound truck when we go to the airport. Maybe, if we're lucky, and the president's task force of space planes does what they're saying it can do, we'll be able to come back and get our truck. Maybe-

"Hey, what are you doing-?"

(Harsh voice off-camera.) "Up yours, bitch-"

(The camera image leaps skyward, but viewers hear sounds of struggle, screams from reporter.)

(Cut to Bruce Kendrick.) "We seem to have developed technical problems with our mobile unit in St. Louis. We'll be going back there as soon as we reestablish contact. Meantime, let's switch over to Jay Hardin, who's standing by at ground zero, in Chase County, Kansas."

2.

Hartsfield SSTO Maintenance Facility. 8:14 A.M.

There were now five SSTOs at Hartsfield. The shipment of pitons lay gleaming in their crates while teams of technicians proceeded with installation.

In an adjoining building, the flight crews were receiving instructions on their new equipment from Orly Carpenter. Carpenter was tall and angular, with a full head of silvery hair that in his astronaut days was such a fiery color it had earned him the nickname "Red." His usual high-energy delivery was subdued that evening, probably because of the nature of the mission, possibly because he was still trying to put the loss of Copenhagen and his niece Wendy's death out of his mind.

They sat in a crowded conference room around a long table designed for half the actual number of attendees. "Ladies and gentlemen," he said, speaking from a lectern in front of a video screen, "welcome to Operation Rainbow." He saw the smiles, some skeptical, some in the best can-do military tradition. "The media have been saying we're going to attempt to lift the Possum into a higher orbit. That's true as far as it goes. We will change its course somewhat. More important, we are going to accelerate it. We are going to speed it up and we are going to move it across Earth's orbit before Earth arrives.

"After your planes have been equipped, we'll take them to Skyport, refuel, and rendezvous with the Possum. We estimate that all seven vehicles will be in position on the rock between three-thirty and four A.M. Since this thing is due to come down at four minutes to five, we won't be much ahead of the curve.

"The SSTOs should have eighteen to twenty minutes burn time left at full throttle when they arrive at the Possum. That's not much. But it will be enough. What's essential is that no fuel be wasted. When we arrive, we'll lock down at our designated spots, and at the designated angles, and shut off the engines. From that point, do nothing without instructions. Questions so far?"

A hand went up, from Ben West, the pilot of the L.A.-based plane. "If I understand this, we're going to burn up most, or maybe all, of our fuel during the operation. Is that right?"

"That's correct, Ben."

"How do we get home?"

Carpenter nodded. "That's a fair question. We'll have ferries standing by. When the mission's been completed, if planes are unable to leave the Possum under their own power, which will likely be the case, the ferries will pick up the crews."

"Orly." Willem Stephan, who had just come back from the Moon. "What happens then? To the SSTOs?" The pilots had a traditional affection for their spacecraft. Casting them loose wasn't entirely appealing.

"Unfortunately," Carpenter said, "we've no immediate way to refuel them. We do expect to get them back eventually. But we're taking this one thing at a time. The objective is to stop the rock, not to save the planes. Anyone else?"

No hands went up.

"Okay. Once you're in place, the pitons will anchor you to the Possum. You'll be able to release from them any time you want, but if you do so the pitons will remain in the ground. You won't be able to reattach. So we only get one shot at this. Everything has to work right the first time.

"The pitons will be handled from the flight engineer's station. You'll need relatively flat ground, and we've tried to pick sites accordingly. If when you get there you don't like the terrain assigned to you, let me know. Don't try anything that looks unduly risky. But tell me before you lock down. Afterward, it's too late. Is that clear to everyone? Please be careful about all this. We're at a point now, if we lose a single vehicle we're in deep trouble.