For safety's sake the third was crashed--at the cost of one guided
missile--when it had come within 50 miles.

The screen of tin cans worked, but it wasn't thick enough. The occupants
of the Platform went about hunting for sheet metal that could be spared.
They pulled out minor partitions here and there, and went out on the
surface and threw away thousands of small glittering scraps of metal in
all directions.

Two weeks later, there was another attack. It could be calculated that
Joe couldn't have carried up more than six guided missiles. There might
be as few as two of them left. So eight rockets came up together--and
the first of them went off 400 miles from the Platform. Only one got as
close as 200 miles. No guided missiles were expended in defense.

The Platform's enemies tried once more. This time the rockets arched up
above the Platform's orbit and dived on the satellite from above. There
were two of them. They went off at 180 and 270 miles from the Platform.
Joe's trash screen would not work on Earth, but in space it was an
adequate defense against anything equipped with proximity fuses. It
could be assumed that in a full-scale space-war nuts, bolts, rusty nails
and beer bottle caps would become essential military equipment.

Three days after this last attack, a second supply ship took off from
Earth. Lieutenant Commander Brown was a passenger. Its start was just
like the one Joe's ship had made. Pushpots lifted it, jatos hurled it
on, and then the furious, flaming take-off rockets drove it valiantly
out toward the stars.

Joe's ship had been moved out of the landing lock and was moored against