The SF Hall of Fame Volume Two B Read Free

screen.
Hilder's voice continued, pointing out features of interest that appeared in
schematic color. The communications system of the ship outlined itself in red
as he talked about it, the storerooms, the proton micropile drive, the
cybernetic circuits . . .
    Then Hilder was back on the screen. "But this is only
the travel-head of the ship. What moves it? What gets it off the Earth?"
    Everyone knew what moved a spaceship, but Hilder's voice was
like a drug. He made spaceship propulsion sound like the secret of the ages,
like an ultimate revelation. Even Rioz felt a slight tingling of suspense, though
he had spent the greater part of his life aboard ship.
    Hilder went on. "Scientists call it different names.
They call it the Law of Action and Reaction. Sometimes they call it Newton's
Third Law. Sometimes they call it Conservation of Momentum. But we don't have
to call it any name. We can just use our common sense. When we swim, we push
water backward and move forward ourselves. When we walk, we push back against
the ground and move forward. When we fly a gyroflivver, we push air backward
and move forward.
    "Nothing can move forward unless something else moves
backward. It's the old principle of 'You can't get something for nothing.'
    "Now imagine a spaceship that weighs a hundred thousand
tons lifting off Earth. To do that, something else must be moved downward.
Since a spaceship is extremely heavy, a great deal of material must be moved
downward. So much material, in fact, that there is no place to keep it all
aboard ship. A special compartment must be built behind the ship to hold
it."
    Again Hilder faded out and the ship returned. It shrank and
a truncated cone appeared behind it. In bright yellow, words appeared within
it: MATERIAL TO BE THROWN AWAY.
    "But now," said Hilder, "the total weight of
the ship is much greater. You need still more propulsion and still more."
    The ship shrank enormously to add on another larger shell
and still another immense one. The ship proper, the travel-head, was a little
dot on the screen, a glowing red dot.
    Rioz said, "Hell, this is kindergarten stuff."
    "Not to the people he's speaking to, Mario,"
replied Long. "Earth isn't Mars. There must be billions of Earth people
who've never even seen a spaceship; don't know the first thing about it."
    Hilder was saying, "When the material inside the
biggest shell is used up, the shell is detached. It's thrown away, too."
    The outermost shell came loose, wobbled about the screen.
    "Then the second one goes," said Hilder, "and
then, if the trip is a long one, the last is ejected."
    The ship was just a red dot now, with three shells shifting
and moving, lost in space.
    Hilder said, "These shells represent a hundred thousand
tons of tungsten, magnesium, aluminum, and steel. They are gone forever from
Earth. Mars is ringed by Scavengers, waiting along the routes of space travel,
waiting for the cast-off shells, netting and branding them, saving them for
Mars. Not one cent of payment reaches Earth for them. They are salvage. They
belong to the ship that finds them."
    Rioz said, "We risk our investment and our lives. If we
don't pick them up, no one gets them. What loss is that to Earth?"
    "Look," said Long, "he's been talking about
nothing but the drain that Mars, Venus, and the Moon put on Earth. This is just
another item of loss."
    "They'll get their return. We're mining more iron every
year."
    "And most of it goes right back into Mars. If you can
believe his figures, Earth has invested two hundred billion dollars in Mars and
received back about five billion dollars' worth of iron. It's put five hundred
billion dollars into the Moon and gotten back a little over twenty-five billion
dollars of magnesium, titanium, and assorted light metals. It's put fifty
billion dollars into Venus and gotten back nothing. And that's what the
taxpayers of Earth are really interested in— tax money out; nothing in."
    The screen was filled, as he spoke, with diagrams of