"They're not doing anything," he murmured.

Bam Gordette, standing slightly behind Doug like a bodyguard, said, "That's the army: hurry up and wait."

Doug thought that the thirty-klicks-per-hour pace of the Peacekeepers' vehicles hardly qualified for hurrying up, but they were definitely waiting now.

The control center had settled into a waiting mode also. Everything that could be done to prepare Moonbase's defenses had been done. Nick O'Malley paced nervously a few consoles away, hoping that his dust would work as he had promised. Vince Falcone and his crew had finally come back from Wodjo Pass, grumbling and griping about the foamgel's intractability but satisfied that they had covered as much of the pass as they could.

Wix and his people are still working on the particle gun, Doug knew. They're the key to our defense, the crucial link in the chain. If they can't stop that nuclear missile we might as well surrender. We'll have to surrender.

Nothing had moved out on the Mare Nubium for at least an hour.

"They're waiting for the missile strike," Doug said to no one in particular.

As if in response, one of the comm techs sang out, "They've launched! Rocket flare from L-l. Their missile's heading our way."

MASS DRIVER

Robert T. Wicksen was still outside, checking the wiring connections from the main magnets to the hastily installed switching panel, when the word came from the control center:

"L-l's launched their bird."

By reflex, he looked up. Instead of the sky he saw the inside of his helmet, dark and confining.

"How much time do we have?" he asked calmly.

"Wait one," the comm tech's voice said in his earphones. Then he heard her muttering, "Doppler plot… burn rate…acceleration—looks like… one hundred fifty-six minutes, according to the computer."

"Two and a half hours, plus six minutes."

"If they don't light a second stage."

"Keep me informed."

"Will do."

Switching to the suit-to-suit frequency, Wix told the four volunteers still working with him, "We have two and a half hours. Double check everything."

The spacesuited figures bent to their work.

"That's the nuke," Doug muttered.

"Must be," said Jinny Anson. Like Doug, she was staring at the screen showing the blunt-nosed missile. It seemed to be hanging in space now that its rocket engine had shut down; the stars in the background did not move.

Two and a half hours, Doug thought. What have we forgotten to do? Looking up, he traced the glowing lines on the electronic map of the base that covered one entire wall of the control center. Water factory, environmental control center, electrical power—they're as protected as they'll ever be. Turning to the insect-eye array of screens at the console he had commandeered, Doug saw displays of Wodjohowitcz Pass and the crater floor. Off near the brutally short horizon he could barely make out the ant-like forms of Wix and his volunteers still tinkering at the mass driver.