no matter from what cause, its enemies
would announce vociferously that it had been destroyed by its own
atomic bombs, exploding spontaneously. Even in the face of proof of
murder, enemy nations would stridently insist that bombs intended for
the enslavement of humanity--in the Platform--had providentially
detonated and removed that instrument of war-mongering scoundrelly
imperialists from the skies. There might be somebody, somewhere, who
would believe it.

Joe and the Chief were steadied now nearly on a line to intercept the
rising manned rocket. They had already fired their missiles, which
trailed them. They went into battle, not prepared to shoot, but with
their ammunition expended. For which there was excellent reason.

Something came foaming toward them from the nearby man-carrying rocket.
It seemed like a side-spout from the column of vapor rising from Earth.
Actually it was a guided missile.

"Now we dodge," said Joe cheerfully. "Remember the trick of this
maneuvering business!"

It was simple. Speeding toward the rising assassin, and with his
missiles rushing toward them, the relative speeds of the wagons and the
missiles were added together. If the space wagons dodged, the missile
operator had less time to swing his guided rockets to match the change
of target course. And besides, the attacker hadn't made a single turn in
space. Not yet. He might know that a rocket doesn't go where it's
pointed, as a matter of theory. He might even know intellectually that
the final speed and course of a rocket is the sum of all its previous
speeds and courses. But he hadn't used the knowledge Joe and the Chief
had.

Something rushed at them. They went into evasive action. And they didn't
merely turn the noses of their space wagons. They flung them about
end-for-end, and blasted. They used wholly different accelerations at
odd angles. Joe shot away from Earth on steering rocket thrust, and
touched off a four-three while he faced toward Earth's north pole, and
halfway along that four-second rush he flipped his craft in a somersault
and the result was nearly a right-angled turn. When the four-three
burned out he set off a twelve-two, and halfway through its burning
fired a three-two with it, so that at the beginning he had two gravities
acceleration, then four gravities for three seconds, and then two again.

With long practice, a man might learn marksmanship in space. But all a
man's judgment of speeds is learned on Eart