A Ride in the Magnesium Gondola

Latest update July 9, 2019 Started on 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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Stevens and Anderson Win the Mackay Trophy for 1935 for their world record stratosphere balloon flight on November 11, 1935.

The Mackay Trophy was first presented by Clarence Mackay in 1912 and was later deeded to the National Aeronautic Association. The trophy is awarded for the "most meritorious flight of the year" by an Air Force person, persons, or organization. The United State Air Force determines the winner and the National Aeronautic Association presents the trophy to the winner. The trophy resides at the Smithsonian Air & Space Museum, Washington, DC.

Presentation photo shows: Capt. Orval Anderson; Charles F. Horner, President National Aeronautical Association; Maj. Albert W. Stevens; Maj. Gen. Oscar Westover; Dr. John Oliver LaGorce, VP, NGS; Dr. Gilbert H. Grosvenor, President, NGS.

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In The Field

On December 11, exactly one month after the successful Explorer II stratosphere balloon flight, the National Geographic Society awards it highest honor, the Hubbard Medal, to Captains Albert W. Stevens and Orvil A. Anderson.

Retired General John J. Pershing, former General of the Armies during the First World War and now a Society trustee presents the Hubbard Medal to Stevens and Anderson.

So great is the demand for tickets to the medal presentation that two ceremonies must be held at Constitution Hall for the Wednesday evening presentation. One is scheduled for 4:45 p.m., and is open to any and all Society members fortunate enough to secure a ticket; while the other, at 8:15 p.m., is reserved for Lecture season ticket holders and invited guests, including most of official Washington.

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The Explorer II attempts it's flight again. This time, SUCCESS!
The flight sets a worlds altitude record of 72,395 feet (almost 14 miles). The temperature measured was 78 degrees below zero, Fahrenheit and the air density only 1/25th of that at sea-level.


This chart puts into perspective the accomplishment achieved by the Explorer II stratosphere balloon flight on November 11, 1935.

In The Field

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.


Explorer Balloon crew awarded Distinguished Flying Crosses
“For extraordinary achievement, while participating in an aerial flight…each officer assisted in piloting the balloon into the stratosphere to an altitude of 60,613 feet, and in making continuous scientific observations in route, and when the balloon became disabled through circumstances beyond human control, did attempt under most adverse and hazardous conditions, to successfully land the disabled aircraft in order to preserve the scientific records that had been obtained.” Major General A. J. Bowley, Commander of the Fifth Corps Area presented the DFC to Major Kepner and Captain Stevens on December 6, 1934 at Wright Field, Dayton. Famed aviator and namesake Orville Wright attended the ceremony. Captain Anderson received his award nine days later at Kelly Field, San Antonio, Texas.

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In The Field

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)


“Miss Amelia Earhart and Mr. George Putnam visited the Stratocamp at about 8:40 pm tonight and made a thorough inspection, posing for pictures with the Flight Personnel.” So stated Thomas McKnew, NGS Asst. Secretary, in his July 13, 1934 daily report from the Stratobowl. Earhart was one of several notable people to visit the launch site. Of course, her visit made front page news in Rapid City, SD.

From L to R: Thomas McKnew, NGS; Lyman J Briggs, NBS; Capt. Stevens; Amelia Earhart; Major Kepner; George Putnam.

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On June 1, 1934, The National Geographic Society began including information about the upcoming NGS – USAAC Stratosphere Balloon Flight in their regularly released GEOGRAPHIC NEWS BULLETIN. The subject was “What is the stratosphere?” Responding to numerous requests from editors for biographical information about Kepner, Stevens, and Anderson, the NGS issued GEOGRAPHIC NEWS BULLETIN #2538 on July 3, 1934. The accompanying photo in this posting was one of a few publicity photos taken by the Air Corps. This photo comes from the NGS – USAAC Stratosphere Balloon collection, Research Division, National Museum of the U.S. Air Force in Dayton, Ohio.

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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)


The bold headline of the May 14, 1934 Rapid City Journal newspaper said it all. Rapid City had successfully secured the NGS - USAAC Stratosphere Flight of 1934. These photos taken during the earlier visit by Major Kepner and Lt. Anderson clearly show why Moonlight Valley was the perfect launch site.

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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.


From as far north as Devils Lake, North Dakota, all the way down to Midland, Texas…from the metropolis of Denver to tiny Alliance, Nebraska…competition is fierce as cities from across the Great Plains compete to see where the Society will decide to launch the Stratosphere flight. Correspondence from these cities and their Chambers of Commerce highlight positive attributes, such as infrastructure, favorable weather, terrain, and low cost of living for the project crew.

Weather and terrain are the most important factors for the Society to consider. Reliably clear skies and low and predictable wind patterns are required for a smooth flight, and to ensure that the balloon does not drift over a large body of water. For this reason, Midland has been ruled out due to the possibility that the balloon could end up over the Gulf of Mexico.

Rapid City, South Dakota was ultimately selected as the location for the Stratosphere flight. The “Stratobowl”, a natural bowl-shaped depression in the Black Hills near Rapid City, provides protection from the wind for inflating the balloon, and the prevailing winds of the region will keep the balloon over dry land. Other cities may be disappointed to not be chosen, but Rapid City will surely prove to be an excellent location for Stratosphere operations.

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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.


On January 17, 1934, the National Geographic Society released a news story about the planned NGS – USAAC Stratosphere Balloon Flight of 1934 scheduled for the coming summer. The story ran in more than 600 newspapers. Thomas W. McKnew, Assistant Secretary, brought this to Major William E. Kepner’s attention in a letter dated January 18, 1934. Kepner was everyone’s first choice to pilot the upcoming flight. In the letter, Kepner is formally embraced by the National Geographic Society. Also presented in this posting is a copy of the article from The Washington Post published on January 17, 1934.

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


By late 1933, Captain Albert W. Stevens had procured the necessary funds and commitments to get two stratosphere flights off the ground. Dated December 18, 1933, Stevens sent a 19-page proposal to The Chief of the Air Corps. The proposal detailed the necessary equipment, instruments, cameras, and personnel that would be required to launch stratosphere ascents in June and September 1934.

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.


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