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A Ride in the Magnesium Gondola

January 1 1933

In 1933, a group of men started an ambitious project to gather data on cosmic rays and other phenomena of the upper atmosphere. They wanted to launch a manned balloon containing a variety of scientific measuring devices high into the stratosphere.

January 1 1933


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Mission Underway

On July 12 a window seems to open and a launch for Explorer II is attempted...

The giant balloon (a 3,500,000 cubic foot bag) is taken out of its box and inflated with helium gas. The gondola is attached, and flight is about to take place but just at that moment, the balloon rips and collapses , so further attempts are postponed until autumn.

Despite the mixed results of the launch last summer, all parties agree that another attempt must be undertaken. A number of modifications, however, should be made to the balloon and gondola. Consequently, the new balloon, made out of a stronger fabric, is even larger than that which lifted the Explorer aloft, and with a capacity of 3,700,000 cubic feet of gas, is the largest yet constructed. Such extra size is needed because helium will now be used in place of hydrogen, which proved so dangerous when it caused the Explorer to explode, and it takes proportionally more helium than hydrogen to raise the balloon 75,000 feet into the stratosphere, which is nearly 15 miles above the earth's surface. A new and improved, hermetically-sealed gondola is then made out of a magnesium alloy lighter than aluminum, and is duly christened Explorer II.

Captain Albert W. Stevens is the commander and oversees the scientific and photographic work, and Captain Orvil Anderson is the pilot. This second launch will again be made from the "Stratobowl" near Rapid City, South Dakota, and is initially scheduled for June.

On July 28, 1934, in the Black Hills of South Dakota, hundreds (including NBC) gathered to watch and record the nail-biting flight of the stratosphere in the "magnesium gondola." Aboard the gondola were Capt. Albert W. Stevens, scientific observer for the flight and one of the foremost aerial photographers of the world , Capt. Orvil A. Anderson, and Maj. William E. Kepner, the pilot. The expedition was sponsored by the National Geographic Society and the U.S. Army Air Corps. Its purpose was to obtain a complete set of data of the physical and chemical conditions of the upper atmosphere.

All seemed to be going well as they rose up through the atmosphere, until at around 60,000 feet, a sudden rip the in the balloon's lower surface...

From Captain Albert W. Stevens' first hand account of the expedition:

Frantically trying to keep the balloon afloat, the men kept maneuvering the balloon gas valve. "Across the gondola stood Major Kepner, his hand on the special lever that would release the 80-foot parachute installed by its designer…Kepner was ready to turn the lever should the balloon suddenly disintegrate. However, when the balloon burst at a much lower altitude, no one was within reach of the lever to release the parachute…Three quarters of an hour passed, and we were down to 40,000 feet….half an hour later we were down to 20,000 feet….Suddenly the entire bottom of the bag dropped out…The bottomless bag was acting largely as a parachute… We now had to lose some of the weight of the gondola, gradually discharging ballast, then strapping on parachutes..." At 2,000 and falling, Stevens and crew leaped out of the gondola and narrowly escaped the balloon explosion. "The gondola dropped like a stone." They all landed in a cornfield in Holdrege, Nebraska. Some of the film and most of the data collected luckily survived the crash, and overall, the flight was still viewed as a success. (National Geographic Magazine. October 1934: 397-434)

Preparation Stage

More preparations for the Stratosphere Flight:

After the twelve hour flight returned to ground, the "automatic" aerial camera was supposed to contain hundreds of feet of film on which the photographic "robots" would have recorded instrument readings.

In New York City, NBC designed special light-weight broadcasting and receiving sets to be carried on the gondola. "For five minutes of each hour Major Kepner and Captain Stevens plan to talk by radio, reporting their progress and describing the appearance of the earth as they rise farther and father above it. Their comments are to be picked up on the ground near by and rebroadcast over a nation-wide network of NBC stations." (National Geographic Magazine. July 1934: 109)


Major William E. Kepner (left) and Captain Albert W. Stevens (right) will pilot the world's largest balloon to the highest safe altitude. At take-off the bag will be shaped like a carrot, its top higher than the roof of a 26-story office building. On reaching the stratosphere, the gas will expand and distend the balloon to its maximum size, large enough to contain an 11-story hotel.


The ball-shaped gondola was completed by the Dow Chemical Company in Midland, Michigan. It consists mostly of magnesium, and was constructed by welding together eight sections of metal shaped like pieces of orange peel. The upper half of the gondola is white in order to reflect away some of the heat from the sun's rays and so prevent an uncomfortably high temperature inside during the middle of the day. The lower half is black to absorb heat rays from the earth.


The 305 foot balloon was built at the Goodyear-Zepplin Corporation in Akron, Ohio and took 9 hours to inflate.

Expedition Background

In early 1933, Captain Albert W. Stevens of the U.S. Army Air Corps proposes to his superiors that the Army undertake an ambitious stratosphere balloon flight. Since the mid-1920s he has been promoting stratosphere balloon flights as the most promising way to gather data on badly understood cosmic rays and similar celestial phenomena.

Stevens estimates he will need to raise $50,000, and in April he approaches the National Geographic Society as one of a number of prospective corporate and individual donors. The Society's Research Committee initially agrees to provide $5,000; but before the year is out it appropriates a further $25,000, convinced that the project, if sucessful, might very well lead to significant scientific results. With this influx of funds, Stevens is only too glad to call his proposal the National Geographic Society -- U.S. Army Air Corps Stratosphere Flight.