he Platform, the two velocities should be exactly equal.

Major Holt's voice came on the Communicator.

"_Joe_," he said harshly, "_I have very bad news. A message came from
Central Intelligence within minutes of your take-off. I--ah--with Sally
I had been following your progress. I did not decode the message until
now. But Central Intelligence has definite information that more than
ten days ago the--ah--enemies of our Space Exploration Project_--" even
on a tight beam to the small spaceship, Major Holt did not name the
nation everybody knew was most desperately resolved to smash space
exploration by anybody but itself--"_completed at least one rocket
capable of reaching the Platform's orbit with a pay-load that could be
an atomic bomb. It is believed that more than one rocket was completed.
All were shipped to an unknown launching station._"

"Not so good," said Joe.

Mike had left his post when Joe took over. Now he made a swooping dart
through the air of the cabin. The midget showed no signs of the fumbling
uncertainty the others had displayed--but he'd been a member of a midget
acrobatic team before he went to work at the Shed. He brought himself to
a stop precisely at a hand-hold, grinning triumphantly at the nearly
helpless Chief and Haney.

Major Holt said in the headphones: "_It's worse than that. Radar may
have told the country in question that you are on the way up. In that
case, if it's even faintly possible to blast the Platform before your
arrival with weapons for its defense, they'll blast._"

"I don't like that idea," said Joe dourly. "Anything we can do?"

Major Holt laughed bitterly. "_Hardly!_" he said. "_And do you realize
that if you can't unload your cargo you can't get back to Earth?_"

"Yes," said Joe. "Naturally!"

It was true. The purpose of the pushpots and the jatos and the ship's
own take-off rockets had been to give it a speed at which it would
inevitably rise to a height of 4,000 miles--the orbit of the Space
Platform--and stay there. It would need no power to remain 4,000 miles
out from Earth. But it would take power to come down. The take-off
rockets had been built to drive the ship with all its contents until it
attained that needed orbital velocity. There were landing rockets
fastened to the hull now to slow it so that it could land. But just as
the take-off rockets had been designed to lift a loaded ship, the
landing-rockets had been designed to land an empty one.

The more