d not know it. So he's blacked out. He refuses to be
anything unless he can be smartest. We'll have to do artificial feeding
and all that until we can get him down to Earth to a hospital." He
shrugged.

"We'd better report this down to Earth," Joe said. "By the way, better
not describe our screen of tin cans on radio waves. Not even microwaves.
It might leak. And we want to see if it works."

Just forty-two hours later they found out that it did work. A single
rocket came climbing furiously out from Earth. It came from the
night-side, and they could not see where it was launched, though they
could make excellent guesses. They got a single guided missile ready to
crash it if necessary.

It wasn't necessary. The bomb from Earth detonated 300 miles below the
artificial satellite. Its proximity fuse, sending out small radar-type
waves, had them reflected back by an empty sardine can thrown away from
the Platform by Mike Scandia forty-some hours ago. The sardine can had
been traveling in its own private orbit ever since. The effect of Mike's
muscles had not been to send it back to Earth, but to change the center
of the circular orbit in which it floated. Sometimes it floated above
the Platform--that was on one side of Earth--and sometimes below it. It
was about 300 miles under the Platform when it reflected urgent,
squealing radar frequency waves to a complex proximity fuse in the
climbing rocket. The rocket couldn't tell the difference between a
sardine can and a Space Platform.

It exploded with a blast of pure brightness like that of the sun.

The Platform went on its monotonous round about the planet from which it
had risen only weeks before. Sanford was strapped in a bunk and fed
through a tube, and on occasion massaged and variously tended to keep
him alive. The men on the Platform worked. They made telephoto maps of
Earth. They took highly magnified, long-exposure photographs of Mars,
pictures that could not possibly be made with such distinctness from the
bottom of Earth's turbulent ocean of air.

There was a great deal of official business to be done. Weather
observations of the form and distribution of cloud masses were an
important matter. The Platform could make much more precise measurements
of the solar constant than could be obtained below. The flickering radar
was gathering information for studies of the frequency and size of
meteoric particles outside the atmosphere. There was the extremely
important