other side of the platform. Their gear was
already loaded. They had only to take seats on the rocket, and their six
years on the space platform would be at an end.

"I wonder what it will be like to get back to high gravity," Rip mused.
The centrifugal force of the spinning platform acted as artificial
gravity, but it was considerably less than Earth's.

"We probably won't be able to walk straight until we get our Earth legs
back," Flip answered. "I wish I could stay in Colorado with you instead
of going back to Mexico City, Rip. We could have a lot of fun in eight
weeks."

Rip nodded. "Tough luck, Flip. But anyway, we have the same assignment."

Both Planeteers had been assigned to Special Order Squadron Four, which
was attached to the cruiser _Bolide_. The cruiser was in high space,
beyond the orbits of Jupiter and Saturn, doing comet research.

They got off the track at Valve Two and stepped through into the rocket's
interior. Two seats just ahead of the fins were vacant, and they slid
into them. Rip looked through the thick port beside him and saw the
distinctive blue glow of a nuclear drive cruiser sliding toward the
platform.

"Wave your eye stalks at that job," Flip said admiringly. "Wonder what
it's doing here."

The space platform was a refueling depot, where conventional chemical
fuel rockets topped off their tanks before flaming for space. The newer
nuclear drive cruisers had no need to stop. Their atomic piles needed new
neutron sources only once every few years, and they carried thousands of
tons of methane, compressed into solid form, for their reaction mass.

The voice horn in the rocket cabin sounded. "The SCN _Scorpius_ is
passing Valve Two, landing at Valve Eight."

"I thought that ship was with Squadron One on Mercury," Rip recalled.
"Wonder why they pulled it back here."

Flip had no chance to reply, because the chief rocket officer took up his
station at the valve and began to call the roll. Rip answered to his
name.

The rocket officer finished the roll, then announced: "Buttoning up in
twenty seconds. Blast off in forty-five. Don't bother with acceleration
harness. We'll fall free, with just enough flame going for control, after
ten seconds of retrothrust to de-orbit."

The ten-second-warning bell sounded, and, before the bell had ceased, the
voice horn blasted. "Get it! Foster, R.I.P., Lieutenant. Report to the
platform commander. Show an exhaust!"

Rip leaped to his feet. "Hold