Mike said truculently, "We won't be knocked off! We've got rockets of
our own up here now! We can fight back if there's another attack!"

Brent shrugged. His face was young enough, but deeply lined. He said as
mildly as before: "Your landing rockets set off four bombs on the way
from Earth. You brought us six more rocket missiles. How many bombs can
we knock down with them?"

Joe blinked. It was a shock to realize the facts of life in an
artificial satellite. If it could be reached by bombs from Earth, the
bombs could be reached by guided missiles from the satellite. But it
would take one guided missile to knock down one bomb--with luck.

"I see," said Joe slowly. "We can handle just six more bombs from
Earth."

"Six in the next month," agreed Brent wrily. "It'll be that long before
we get more. Somebody sent up four bombs today. Suppose they send eight
next time? Or simply one a day for a week?"

Mike made an angry noise. "The seventh bomb shot at us knocks us out!
We're sitting ducks here too!"

Brent nodded. He said mildly:

"Yes. The Platform can't be defended against an indefinite number of
bombs from Earth. Of course the United States could go to war because
we've been shot at. But would that do us any good? We'd be shot down in
the war."