quation when he
stumbled over a thorium crystal. He went headlong, shooting like a rocket
three feet above the ground. His board flew away at a tangent. His stylus
sped out of his glove like a miniature projectile, and the slide rule
clanged against his bubble.

It happened so fast that neither Koa nor Santos had time to grab him. The
action had given him extra speed, and he saw with horror that he was
going to crash into Trudeau. He yelled, "Frenchy! Watch out!" Then he put
both hands before him to protect his helmet. His hands caught the French
Planeteer between the shoulders.

CHAPTER SEVENTEEN

Visitors!

Trudeau held tight to the launcher, but the rocket racks opened and
spilled attack rockets into space. They flew in a dozen different
directions. Trudeau gave vent to his feelings in colorful French.

Koa and Santos laughed so hard they had trouble collecting the scattered
equipment. Rip, slowed by his crash with Trudeau, got his feet under him
again.

When the asteroid turned into the sun, they still had not collected Rip's
stylus and five of the attack rockets. The space pencil was the only
thing that could write on the computing board. It had to be found. "Next
time around," Rip called to the others. He then led the way full speed
ahead until they reached the safety of shadow again.

Rip suspected the stylus was somewhere above the rock and probably
wouldn't return to the surface for some minutes. While he was wondering
what to do, there was a chorus of yells. A rocket sped between the
Planeteers and shot off into space.

"Our own rockets are after us," Trudeau gasped. There hadn't been time
to collect them all after Rip's unwilling attack on the Frenchman had
scattered them. Now the sun was setting them off. Another flashed past,
fortunately over their heads. The sun's heat was causing them to fire
unevenly.

"Three more to go," Koa called. "Watch out!"

Only two went, and they were far enough away to offer no danger.

Santos had been fishing around in the instrument case. Suddenly he
produced another stylus. "It was under the sextant," he explained
triumphantly.

"If we get through this, I'll propose you for ten more stripes," Rip
vowed. "We'll make you the highest ranking sergeant that ever made a
private's life miserable."

Working slowly but more safely, Rip figured that slightly more than two
and a half tubes would do the trick.

Now to fire them. That meant finding a thorium cry