rather important to pass on," and told about
the newly discovered physical effects of a long stay where there was no
gravity. The doctors now predicted that anybody who spent six months
without weight would suffer a deterioration of muscle tone which could
make a return to Earth impossible without a long preliminary process of
retraining. One's heart would adjust to the absence of any need to pump
blood against gravity.

"Which," said Joe, "means that you're going to have to be relieved
before too long. But we brought up some gravity-simulator harness that
may help."

Brent said desolately: "And I was so pleased! We all had trouble with
insomnia, at first, but lately we've all been sleeping well! Now I see
why! Normally one sleeps because he's tired. We had trouble sleeping
until our muscles got so weak we tired anyhow!"

Another drone came in and was unloaded. And another and another. But the
last of them wasn't only unloaded. Haney took over the Platform's
control board and--grinning to himself--sent faint, especially-tuned
short wave impulses to the steering-rockets of the drone. The
liquid-fuel rockets were designed to steer a loaded ship. With the
airlock door open, the silvery ship leaped out of the dock like a
frightened horse. The liquid-fuel rocket had a nearly empty hull to
accelerate. It responded skittishly.

Joe watched out a port as it went hurtling away. The vast Earth rolled
beneath it. It sped on and vanished. Its fumes ceased to be visible. Joe
told Brent:

"Another nice job, that! We sent it backward, slowing it a little. It'll
have a new orbit, independent of ours and below it. But come sixty hours
it will be directly underneath. We'll haul it up and refuel it. And our
friends the enemy will hate it. It's a radio repeater. It'll pick up
short-wave stuff beamed to it, and repeat it down to Earth. And they can
try to jam that!"

It was a mildly malicious trick to play. Behind the Iron Curtain,
broadcasts from the free world couldn't be heard because of stations
built to emit pure noise and drown them out. But the jamming stations
were on the enemy nations' borders. If radio programs came down from
overhead, jamming would be ineffective at least in the center of the
nations. Populations would hear the truth, even though their governments
objected.

But that was a minor matter, after all. With space ship hulls coming
into being by dozens, and with one convoy of hundreds of tons of
equipment got