Evening star., 1935-03-10
By Thomas X. Henry.
. MOTHER stratosphere expedi-
a tinn this Summer.

~ ton this summer.
II Mans most ambitious ef-
4 \ fort to date to penetrate the
mysterious region where the
stars shine at MONDAY will be made
in a few months under the joint
auspices of the National Geographic
Society and the United States Army
Air Corps.
In sense it will be second voyage
Of the sort. The fight made from
the Black Hills last July ended nearly
IL miles above the earths surface
when the bag of the balloon Explorer
started to rip and forced a descent
which ended in smash. But a great
deal has been learned about strato-
sphere exploring since then. Some OF
the country's foremost physicists have
been at work on the problem and have
determined just where the mistakes
were made last year.
This year Capt. Albert w. Stevens
and Capt. Orvil A. Anderson will start
out for the stratosphere with a bigger
balloon. more substantially construct
ed and with the defects which caused
the crash of the Explorer eliminated.
The ascent will again be made from
the vicinity Of Rapid City, S. Oak.
Capt. Stevens will be In command OF
the largest balloon ever constructed
a bag which exceeds by % per cent the
capacity of the 5000, ,000-cubic foot
Explorer. This, in turn, was more
than three times the size of any bal
loon previously built. The new bag
will have diameter, when filled, of
1872 feet and gas capacity of 3,700,000
cubic feet.
EOR the first time, helium gas will
be used for a StratoSphere fight.
This will make it possible to eliminate
all danger of torn fabric and eXplo-
sion, such as was suffered by the
hydrogen-f1lled Explorer. Helium is
non-explosive, either alone or when
mixed with air It will not be neces-
sary. therefore, that the fabric of the
bag be folded to exclude air when the
balloon leaves the ground. The bag
will have helium at its top and air in
its lower portion, and will be loosely
extended. When it reaches high alti-
tudes the expansion of the helium in
the top will force out the air through
an opening in the bottom and the
bag then will be completely filled with
helium. This procedure has been fol-
lowed successfully even with hydro
gen in the three flights made by the
Piccards, but there is always danger
of an explosion from mixture of
hydrogen and air. With helium an
explosion is impossible
The new bag will have top Of SO
per cent stronger fabric and bot
tom of so per cent stronger fabric
than that used in last years balloon.
It is because Of the increased weight
of the stronger fabrics, and the fact
that helium has only about nine
tenths Of the lifting power of hydro
gen, that the new balloon is being
made larger. The increase of about
% per cent In gas capacity will give
the helium- filled bag about the same
theoretical ceiling as that of the
hydrogen bag last July. This is about
$4,000 feet above sea level, or between
il and Is miles.
The ascent should reach the greatest
altitude yet attained by man. Since
the Belgian physicist, August Picard,
made his first stratosphere trip in
May, 1881, the record has been as
follows:
Picard and Cosyns, Belgium, Au-
gust 18, 1882; volume of balloon,
100000 cubic feet; altitude attained,
63,153 feet.
Prokovieff and Godounoff, Russia,
September 80, 1888; volume of balloon,