copper
discs about twelve feet in diameter--the ship will have to be more of a
disc than a cylinder. I think a ship a hundred and eighty feet long,
fifty feet wide, and twenty feet deep will be about the best dimensions.
The power units will be strung along the top of the ship in double
rows--one down each side of the hull. In the middle will be a series of
fused quartz windows, opening into a large room just under the outer
shell. We'll obviously need some source of power to activate the power
tubes that run the molecular motion power units. We'll have a generator
run by molecular motion power units in here, absorbing its heat from the
atmosphere in this room. The air will be heated by the rays of the sun,
of course, and in this way we'll get all our power from the sun itself.

"Since this absorption of energy might result in making the ship too
cool, due to the radiation of the side away from the sun, we'll polish
it, and thus reduce the unlighted side's radiation.

"The power units will not be able to steer us in space, due to their
position, and those on the sides, which will steer us in the atmosphere
by the usual method, will be unable to get the sun's power; they'll be
shaded. For steering in space, we'll use atomic hydrogen rockets,
storing the atomic gas by the Wade method in tanks in the hold. We'll
also have a battery down there for starting the generator and for
emergencies.

"For protection against meteors, we'll use radar. If anything comes
within a dozen miles of us, the radar unit covering that sector will at
once set automatic machinery in operation, and the rockets will shoot
the ship out of the path of the meteor."

All that day Arcot and the others discussed the various pieces of
apparatus they would need, and toward evening Fuller began to draw rough
sketches of the different mechanisms that had been agreed upon.

The next day, by late afternoon, they had planned the rough details of
the ship and had begun the greater task of calculating the stresses and
the power factors.

"We won't need any tremendous strength for the ship while it is in
space," Arcot commented, "for then there will be little strain on it.
It will be weightless from the start, and the gentle acceleration will
not strain it in the least, but we must have strength, so that it can
maneuver in the atmosphere.

"We'll leave Earth by centrifugal force, for I can make much better
speed in the atmosphere where there is plenty of