t of the screen was the area dead ahead. Rip watched and saw several
blips on it that indicated asteroids. They were all small. He watched,
interested, as the cruiser overtook them. Once, according to the screen,
the cruiser passed under an asteroid with a clearance of only a few
hundred feet.

"You didn't miss that one by much," Rip told the space officer.

"Don't have to miss by much," he retorted. "A few feet are as good as a
mile in space. Our blast might kick them around a little, and maybe
there's a little mutual mass attraction, but we don't worry about it."

He pointed to a blip that was just swimming into view, a sharp green point
against the screen. "We do have to worry about that one." He selected a
lever and pulled it toward him.

Rip felt sudden weight against his feet. The green point on the screen
moved downward below center. The feeling of weight ceased. He knew what
had happened, of course. Around the hull of the ship, set in evenly spaced
lines, were a series of blast holes through which steam was fired. The
steam was produced instantly by running water through the heat coils of
the nuclear engine. By using groups or combinations of steam tubes, the
control officer could move the ship in any direction or set it rolling,
spin it end over end or whirl it in an eccentric pattern.

"How do you decide which tubes to use?" Rip asked.

"Depends on what's happening. If we were ducking missiles from an enemy,
I'd get orders from the commander. But to duck asteroids, there's no
problem. I go over them by firing the steam tubes along the bottom of the
ship. That way, you feel the acceleration on your feet. If I fired the top
tubes the ship would drop out from under those who were standing. They'd
all end up on the ceiling."

Rip watched for a while longer, then wandered back to Commander O'Brine.
He was getting anxious. At first, the task of capturing an asteroid and
moving it back to earth had been rather unreal, like some of the problems
he had worked out while training on the space platform. Now he was no
longer calm about it. He had faith in the Terra base Planeteer
specialists, but they couldn't figure everything out for him. Most of the
problems of getting the asteroid back to earth would have to be solved by
Lieutenant Richard Ingalls Peter Foster.

A junior space officer suddenly called, "Sir, I have a reading at two
seventy degrees, twenty-three degrees eight minutes high."

Commander O'Brine ju