ight 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, 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 overhead."

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 out everything for him. Most of the
problems of getting the asteroid back to Earth would have to be solved by
Lt. 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 jumped up so fast that the action shot him to the
ceiling. He kicked down again and leaned over the officer's 'scope.
Rip got there by pulling himself right across the top of the chart table.

The green point of light on the 'scope was bigger than any other he had
seen.

"It's about the right size," O'Brine said. There was excitement in his
voice. "Correct course. Let's take a look at it."

All hands gripped something with which to steady themselves as the
crui