d Kemp. At his direction, the torchman sliced a thin slot up the
face of the crystal. Rip fitted the wires into it and held them in place
with a small wedge of thorium.

Kemp cut a plug, fitted it into the hole, and welded the seams closed. The
tube was sealed. When electric current fired the rocket head, the thorium
carrying the plutonium wedge would be driven forward to meet the wedge in
the back. And, unless Rip had miscalculated the mass of the two pieces,
they would have their nuclear blast. Rip surveyed the crystal with some
anxiety. It looked right.

Dominico already had rigged the timer from the atomic bomb. He connected
the wires, then looked at Rip. "Do I set it, sir?"

"Load the communicator, the extra bomb parts, the rocket launcher and
rockets, the cutting equipment, my instruments, and the tubes of fuel,"
Rip ordered. "Leave everything else in the cave."

The Planeteers ran to obey. Rip waited until the landing boat was nearly
loaded, then told Dominico to set the timer for five minutes. He wondered
how they would explode the second charge, since they had only the one
timer left, then forgot about it. Time enough to worry when faced with the
problem.

"I'll take the snapper-boat," he stated. "Santos in the gunner's seat. Koa
in charge in the landing boat. Dowst pilot. Let's show an exhaust."

He fitted himself into the tight pilot seat of the snapper-boat while
Santos climbed in behind. Then, handling the controls with the skill of
long practice, he lifted the tiny fighting rocket above the asteroid and
waited for the landing boat. When it joined up, Rip led the way to safety.
As he cut his exhaust to wait for the explosion, he sighted past the
snapper-boat's nose to the asteroid.

He was moving, and the direction of his move told him the sun was already
pulling. Its pull was strong, too. He cut his jets back on, just to hold
position, and saw Dowst do the same.

Another few miles toward the sun and the landing boat wouldn't have the
power to get away from Sol's gravity. A few miles beyond that, even the
powerful little snapper-boat would be caught.

Below, the timer reached zero. A mighty fan of fire shot into space. The
asteroid shuddered from the blast, then swerved gradually, picking up
speed as well as new direction.

Rip swallowed hard. Now they were committed. They would reach a new
perihelion far beyond the limits of safety. P for perihelion and P for
peril. In this case, they were the s