call me?" asked Arnold, appearing silently.

"Yeah," said Banner, "how'd you like to help?"

"Sure, what you got."

"Couple sleds are out of phase. You and Harcraft are going to slip into
suits and go out and find the trouble."

Arnold shrugged, "O.K. with me, when do we start?"

"Pretty quick," said Banner, who had turned to look at the ship's
spec-scanner. "Looks like we're in a belt of meteorites. We'll be able
to match velocities, but we could still be creamed if the path gets too
eccentric. Show him the way, Harcraft. I don't want to take any longer
than necessary, either. Understand?"

Fifteen minutes later, both Arnold and Harcraft were out of the air
lock, each clutching a new phase unit. Harcraft called instructions to
Arnold over his suit's inter-com, but within minutes the smaller man
was, if anything, more adept at the business of maneuvering himself
through the void than his teacher. They replaced the phase unit in the
first sled--the fiftieth from the ship--with Harcraft doing the work
and Arnold watching.

"Can you do the next one alone?" Harcraft asked.

"Easy as pie," Arnold said. "Where is it?"

"About two hundred sleds farther back. Numbers on the side. Number two
hundred sixty-three. Can you remember?"

"I ain't dumb. Where you gonna be?"

"Back in the ship. We'll be waiting for you."

* * * * *

Back again in the control cabin with Banner, Harcraft was about to
congratulate himself on inventing the apprentice system, when a
piercing scream brought both men to their feet. "It's Arnold," Banner
said. "Arnold, you all right?"

Harcraft pushed Banner away from the speaker. "Arnold, what's wrong,
you O.K.?" The speaker remained silent.

"You better suit up," Banner said quietly.

"Yeah," Harcraft said, staring dumbly at the speaker. "Yeah, I better
suit up."

"Wait. Better take a look on the viewscreen."

"Hey, he's coming this way! Quick, get ready at the air lock!"

It was fifteen minutes before they could get anything out of him, and
then he wasn't too coherent. They gave him an injection of herodine to
quiet him down, but his eyes still rolled wildly and all he could
manage was: "Big hunk of rock ... big hunk of rock ... rock, quick ...
monkey ships."

"Any idea what he's talking about?"

"No," Banner said thoughtfully. "There was a sizable meteorite that
came pretty close while you were on your way back to the ship, but I'd
alread