Evening star., 1961-08-13
Space 7 roveI urns
On WeiqhtIessness
BY WILLIAM HINES
Star Science Writer

By WILLIAM HINES
Star Science Writer
CoSmonaut Gherman Titov's
25-hour orbital ride has swept
away some, but not all. of the
cobwebs of mystery and concern
about that strange phenomenon of
space-travel known as weightless-
ness. AS was hoped and more
than half expected, Titov showed
that men can survive the expert
ence without undue distress, even
if the weightless state is not an
unalloyed pleasure.
Titov told press conference in
Moscow Friday that he was off
his feet early in the flight, prob
ably due to the sustained weight
lessness and excitment." And q
Soviet scientist said the centers
of balance in the coSmonaut's
inner ear went awry for q while.
He will be closely observed for
long-range effects.
The One Big Problem
Weightlessness is the one big
space-flight factor that cannot be
precisely duplicated or studied
closely on earth, and can be
created in airplanes for only a
minute or two. In suborbital
rocket flights like those of Mer-
curry Astronauts Alan Shepard
and Virgil Grissom, weightless-
ness lasts for only few minutes.
Weightlessness, so called, is
exactly that-the sensation on the
part Of the subject that he does
not weigh anything. In weight
less state objects like lead balls
float in the air as buoyantly as
eas-filled balloons.
To understand weightlessneSS,
it is necessary to get a clear idea
Of what weight" is. Weight is the
effect of the force Of gravity
acting on mass. Thus, the earth
attracts the mass of a 180-pound
man in such q way as to make
him feel as If he weighs 180
pounds. On the moon the same
man would have the same mass,
but would feel like a 30-pounder
because the moons gravity is only
one-sixth that of earth. In orbit,
he would float around his cabin
like the lightest feather; inde-
pendent of gravity, he would be
weightless. even though his mass
had not changed. This is called
"zero-g." just as the earth's at
traction is "one-g" and the moons
"one-sixth-g."
Making Satellites WeiehtIess
A satellite in orbit becomes
weightless in this way: When it
achieves a velocity of about 1880
miles an hour relative to the
earth, the horizontal velocity of
the ship and the vertical pull of
gravity cancel each other out, so
to speak. The satellite, no longer
in powered flight, falls toward
the center of the earth. At the
same time it forges ahead on its
original course. The combined
results of the two motions-ver-
tical and horizontal-is that the
satellite falls around the earth,
not down on to it.
A space ship on q trip to the
moon or Mars would have to
attain a higher velocity-about
$4,000 miles an hour. It could
then shut off power and coast
out Of the earth's field of gravi-
rational influence. In either case.
the satellite or space ship and
everything in it become weight
less at the instant powered flight
ceases.
Since power will be applied for
only q matter of minutes even
on q week-long round-trip to the
moon, it. is obvious that weight
leSsnesS will be the ordinary con-
dition Of space travellers.
There are two ways of avoiding
weightlesSness, only one of them
Of value for orbiting satellites.
That way is to impart "arti-
ficial g" to the satellite Git would
work on q space ship, too) by
spinning it slowly around its axis.
A very few revolutions a minute
would set up a centrifugal force
that would have the effect of
partial g. Some experts fear it
would also make the passengers
dizzy.
Constont Aceelerotion
The other way-good only for
spaceShips-is to apply constant
acceleration. Acceleration, like the
earth's gravity, can be measured
in g, one & Of acceleration being
an increase in speed Of 80 feet
per second every second. One
tenth-g could be applied to a
spaceship by increasing its speed
80 feet per second each second.
This would get the ship up to
some pretty impressive velocities
in a short while; it would also use
a tremendous amount of power.
Either way, the cure" for
weightlessness is so drastic that
space scientists are hoping no
cure will be indicated. Ttov's Is
hour ride was cheering news in
this respect; for him the weight
less state apparently was mo
Sweatski," as they say in the So
Wet Space Corps, once he got used
to it.
Early space researchers, with
nothing more than fancy to 60 on,
suggested that since zero-g was
actually state of free fall" men
in space might be gripped by a