"The Randolph Field lab can tell you," he said. "The coffee would stay
right there in the air. So would the cup, if you let go of it. But
there's a more serious angle--your breath."

"You'd have artificial air," I began.

"Yes, they've already worked that out. But what about the breath you
exhale? It contains carbon dioxide, and if you let it stay right there
in front of your face you'd be sucking it back into your lungs. After
a while, it would asphyxiate you. So the air has to be kept in motion,
and besides that the ventilating system has to remove the carbon
dioxide."

"What about eating?" I asked. "Swallowing is partly gravity, isn't
it?"

He nodded. "Same as drinking, though the throat muscles help force the
food down. I don't know the answer to that. In fact, everything about
the human body presents a problem. Take the blood circulation. The

{p. 104}

amount of energy required to pump blood through the veins would be
almost negligible. What would that do to your heart?"

"I couldn't even guess," I said.

"Well, that's all the Aero-Medical lab can do--guess at it. They've
been trying to work out some way of duplicating the effect of zero
gravity, but there's just no answer. If you could build a machine to