Evening star., 1958-05-01
EXPLORER
From First Page

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would receive aloft is not i'm
mediately lethal. You might
live some years and then get
a little anemic and wan as if
you needed vitamins."
Space Not InhOspitabIe
Aside from the radiation dan
ger. space appears to be no
more inhospitable than scien-
lists had expected it to be.
Reports on temperature con-
troll and micrometeoriteS indi-
cate that space travellers will
not face any real danger Of
being burned alive, frozen to
death or peppered with lethal
coSnic dust.
The reports were the first to
be made public in connection
with outer-space activities of
the international Geophysical
Year. Data from the two Ex-
plorers is being furnished ICY
headquarters at Brussels.
Moderate at Lower Levels
DR.. Van Allen said cosmic
radiation was moderate at the
lower parts of the Explorers
orbits, in the neighborhood of
200 to 300 miles. But at the
points where the satellites were
farthest away from the earth,
the radiation activity increased
a thousandfold.
When the geiger counters
jammed from too much radia-
ton, DR.. Van Allen said. 1T
took some detective work to
find out what was going on"
Explorer I, termed 1853
alpha by scientists, was launch
ed January 81 and revolves
around the earth in 1l4.S min
utes at distances ranging from
224 miles to 1873 miles.
Both satellites have their
apogees - greatest distance
from the earth-in the south
ern hemisphere. 1t was at
points below the equator that
the greatest radiation activity
was noted.
Explorer I Now Tumbling
In addition to the presence
Of a radiation zone, a number
of curiosities were uncovered.
One was an indication that the
atmosphere is much denser far
from earth than had been be-
lieved. Another was that Ex-
plorer I. a pencil-shaped object
which was launched with a
spin, now has stopped spinning
and is tumbling end-over- -end.
Although the atmosphere at
230 miles is IA times as dense
as had previously been thought,
it is still almost unimaginably
thin. A cubic mile of it would
weigh only 2 ounces. At sea
level, it was calculated, the at
mosphere is 100 billion times
this dense.
DR.. G. F. Schilling of the
Smithsonian Astrophysical OBJ
Servatory at Cambridge, Mass,
said Explorer I may stay in
orbit until the end of 1862. The
prediction was made in con-
nection with atmospheric stud
les that showed the air at 230
miles altitude to be IA times as
dense as had been believed.
DR.. Schilling also cited
studies made by DR.. Charles
Whitney which revealed the
change in Explorer rs spin.
The alteration from long-axis
rotation to a short-axis tumble
occurred in the first 500 trips
the satellite made around the
earth, he said.
Space Reasonably Empty
Micrometeorite studies were
carried out with two types of
instruments. Sensitive to cos
mic particles only millionths
of an inch in diameter, the
teorite gauges showed
empty space" to be reasonably
empty after all. A microphone-
type gauge has detected seven
hits, and another gauge, using
wire less than thousandth
Of an inch in diameter has in
dicated only one hit.
DR.. Edward Manring, who
delivered the paper on meteor
ties, quoted figures which ap-
peared to show that an object
the size of Explorer was likely
to be hit by a dust Speck 4/l0.-
900 of an inch in diameter only
about once every hour. -Four
ten-thousandths of an inch is
about one-tenth the thickness
of a human hair.
Though such micrometeor-
ties are not big enough to do