Explorer Over Dakota

from Stratobowl to Stratosphere

by Steven A. Ruffin

One year after the disastrous high altitude balloon flight of 1934, a record was finally set that would stand unchallenged for the next two decades.


Shortly after sunrise on July 28, 1934, 50,000 spectators, scientists, and newsmen from agencies around the world, gathered to see history made. Crowded atop a ring of cliffs that overlooked a natural depression in the Black Hills of western South Dakota, the crowd watched as a gigantic hydrogen-filled balloon—three times larger than any other ever built—slowly ascended with its crew of three into the cloudless South Dakota sky. The liftoff had been letter-perfect, and as the multitude watched the giant craft drift sedately upward and eastward out of sight, even the most pessimistic viewer could hardly have imagined a more disastrous ending to the flight than that which was about to occur.

This unprecedented scientific expedition was the culmination of a complex, well-organized venture sponsored jointly by the National Geographic Society and the budget-constrained U.S. Army Air Corps. The primary objective of the ambitious undertaking was to explore the upper part of the atmosphere that begins 7-10 miles above the earth’s surface—the mysterious region known as the stratosphere—and in so doing, to also take man to the highest altitude ever achieved.

The painstaking planning and preparation seemed to be paying dividends, as the flight proceeded exactly as expected. The three veteran U.S. Army Air Corps balloonists, sealed in their pressurized metal sphere, ascended higher and higher through the peaceful, nearly airless vacuum at 50,000 feet. As they approached increasingly closer to the existing world altitude record of just over 61,000 feet, they optimistically continued to record data from the dozens of sophisticated scientific instruments they carried aloft with them.

Suddenly, as the giant balloon and gondola climbed through 57,000 feet, disaster struck. In the near-vacuum environment of the upper stratosphere, shearing forces from the expanding hydrogen gas contained within the balloon envelope ripped through the rubberized cotton balloon fabric. Several tears resulted—the largest, a gaping 30-foot hole. As the stricken balloon began to lose its buoyant hydrogen gas, it quickly leveled off at just over 60,000 feet—only 624 feet short of the existing record. It then began a steadily accelerating descent to the ground over 11 miles below. For the three men aboard the imperiled craft, the dream of a world record had been rudely disrupted and was about to be replaced by a nightmarish struggle for survival.


High altitude balloon flights were very much in vogue in the early 1930s—so much that between 1931 and l934 alone, the altitude record had changed hands on at least four different occasions. In 1932 a Swiss physicist by the name of Auguste Piccard had managed to ascend to over 10 miles above the earth’s surface in a sealed, pressurized capsule, while in late 1933, U.S Navy Lt. Commander T.G.W. Settle and Marine Corps Major Chester L. Fordney extended the record to 61,237 feet.

This was the existing record to beat when the National Geographic Society and the U.S. Army Air Corps decided to pool resources and cosponsor a balloon flight in 1934. Although the flight was primarily set up as a scientific expedition to explore atmospheric conditions in the stratosphere, it was the secondary goal of establishing a new high-altitude record that attracted world-wide attention.

By previous arrangement, the Air Corps would supply the crew for the flight. Major William E. Kepner, the commanding officer of the expedition, and alternate pilot, Captain Orvil A. Anderson, were both highly experienced airship and balloon pilots. The third crewman, Captain Albert W. Stevens, was the one who had originally conceptualized and proposed the ambitious joint undertaking. A world-renowned aerial photographer and scientist in his own right, he was designated the scientific observer for the flight.

The three Army crew members were aware of the hazards they were about to face. The dangers for humans venturing into the hostile, unforgiving, and still virtually unknown environment which exists several miles above the earth were numerous, and these perils were underscored by several well-documented misadventures suffered by previous high-altitude explorers. Injury or death from frostbite, oxygen starvation, sudden decompression, or a long uncontrolled plunge to the earth below, were the risks that had to be accepted by the pioneer airmen ascending into the dangerous stratosphere.

In 1927—less than six years before the proposed National Geographic-Air Corps flight—fellow U.S. Army balloonist, Capt. Hawthorne C. Gray, mysteriously died after he had ascended in an open basket to just over 42,000 feet. Orvil Anderson was particularly cognizant of this tragedy, since it was he who had flown the chase plane for Gray. And only six months prior to Kepner, Anderson and Stevens’ planned flight, three Russian balloonists had plunged to their deaths after reaching an unprecedented 72,200 feet, a world record had they returned alive. Clearly, the stratosphere was still a powerful and deadly force to be reckoned with.

Much had been learned from previous flights, despite the tragedies which had occurred. Information gained during Piccard’s and Settle’s ascents in closed capsules had been especially useful; however, the extreme weight of the “floating laboratory” to be carried aloft during the proposed National Geographic-Air Corps expedition necessitated even further technological advances. Designing and acquiring the massive balloon needed to carry a payload of several tons to the very edge of outer space required the best balloon technology which existed at the time. Such expertise proved to be readily available from the Goodyear-Zeppelin Corporation in Akron, Ohio, builder of the U.S. Navy dirigibles Akron and Macon. They were contracted to build the balloon, and after five months’ construction time, the mammoth balloon was ready for flight.

The giant balloon, appropriately christened The Explorer, was truly an awesome sight. Over three times larger than any other balloon ever built up to that time, it boasted a capacity of 3 million cubic feet and measured approximately 300 feet tall during liftoff—higher than a 27-story office building. When fully inflated at higher altitudes, it was as wide and deep as it was high, large enough to enclose an 11-story building sideways. The envelope of the balloon consisted of two and a third acres of rubberized, specially selected cotton fabric, which by itself weighed over two and a half tons. It would require nine hours just to inflate the immense bag with hydrogen—the lightest and most buoyant substance in the universe, but unfortunately also one of the most explosively flammable.

A sealed, pressurized compartment would also be required for the upcoming flight. Not only was the capsule necessary to house the dozens of data-collecting instruments and various other pieces of scientific equipment needed for the flight, but more importantly, it was essential to protect the crew members from high altitude atmospheric conditions incompatible with human life. To serve this purpose, a spherical gondola, to be suspended below the huge balloon envelope of The Explorer, was built by the Dow Chemical Company at Midland, Michigan.

The gondola was precisely 100 inches (eight and one-third feet) in diameter and had a wall thickness of only 3/16 inch. It was constructed with a revolutionary new material called Dowmetal, an alloy consisting of 95% pure magnesium. This material was chosen not only because of its strength, but also because it weighed one-third less than aluminum. Glass portholes were strategically located at various places so the crew could see outside the metal ball.

The main purpose of the flight was to gather various types of scientific data from the stratosphere—in all 63 research studies were scheduled; hence, an impressive array of instruments and data-collecting equipment would have to be carried aloft. These came from laboratories and workshops all over the world and included radio and photographic gear, barometers, altimeters, and other flight instruments. Also carried were various sophisticated data-gathering instruments for obtaining outside air samples, and for studying cosmic radiation and the ozone layer.

The total weight of all the components—balloon, gondola, crew, equipment, and necessary ballast—was close to eight tons, and the final cost was a substantial 60,000 Depression-era dollars. To offset the financial loss in the event of a flight-related accident, The Explorer and equipment—as well as the lives of the crew—were insured by Lloyd’s of London.

The only remaining problem was to locate a suitable location where the skyscraper-sized balloon could be safely launched. Due to the uniquely specific requirements of The Explorer, this proved to be a challenging dilemma. A site was needed where the balloon could be fully inflated over a several hour period to over 300 feet high yet be unaffected by winds. The availability of good landing areas within a several-hundred-mile radius of the launch site was also a must, which in effect ruled out coastal and mountainous areas. Finally, the launch site had to be in an area with generally good weather for not only balloon flight, but also the anticipated collection of a wide range of scientific data.

The ideal location was soon discovered. After the National Geographic Society publicly announced that a launch site was being sought for their upcoming high-altitude balloon flight, numerous suggestions were received from public-spirited citizens and organizations across the country. Pilots Kepner and Anderson dutifully traveled to these locations and examined them. However, when Kepner flew over a cliff-encircled, level grassy meadow nestled in the Black Hills of western South Dakota, he is reported to have exclaimed, “God made that spot for a stratosphere flight!”

The striking, natural depression, resembling an amphitheater, was immediately dubbed the “Stratosphere Bowl” or more simply, the “Stratobowl.” Located approximately 11 miles southwest of Rapid City—midway between this picturesque resort town and an obscure granite mountain named after a man named Rushmore, which was currently having some former presidents’ faces carved into the side of it—the Stratobowl seemed ideal for its selected purpose. Completely encircled by steep hills and sheer cliffs extending over 400 feet above its base, the Stratobowl would allow a balloon even as large as The Explorer to be fully extended above the ground during inflation yet remain protected from the winds.

In addition, the surrounding Northern Plains region was characterized by generally good terrain for landing a balloon, while meteorological conditions in the Black Hills area were judged to be nearly perfect for the proposed expedition.

The Stratobowl was therefore leased from the mining company that owned it and a road built down into the basin, so that numerous truckloads of delicate supplies and equipment, as well as hundreds of personnel, could be transported to the launch area. Soon, a bustling tent city, the “Stratocamp,” emerged to house the various technicians, scientists, and specially trained troops required to launch the largest balloon ever built. Sawdust streets were “paved”, and drainage, water, sewage, and electrical systems established. Even a makeshift hospital with an ambulance was set up and a fire department created. Telephone and telegraph lines, as well as two radio stations, kept the Stratocamp in communication with the outside world, while the weather station set up in the camp was equal to any other in the United States.

So, with all preparations made—a top-notch, well-equipped crew, and an ideal launch site selected and ready—the proposed excursion into the stratosphere was scheduled for the summer of 1934. As the time for launch drew nearer, the world seemed to converge on the Black Hills. An estimated 50 to 60 thousand spectators braved the cool early morning air to see The Explorer off on its historic flight. To prevent sightseers from falling or being pushed off the cliffs to the floor of the Stratobowl below, a full mile of peeled spruce rail restraining fence was built along the rim to hold the mob of spectators back.


But now, eight hours after liftoff and eleven miles above the earth, as the balloon envelope continued to unravel, all the meticulous preparations seemed increasingly meaningless. The three crewmen hastily discussed the situation. If the remaining balloon envelope held together, there was still a chance for crew, equipment and gondola to return safely to earth. Status reports were regularly relayed by radio from The Explorer to those observing below throughout the descent. These reports were then rebroadcast over a nation-wide network of National Broadcasting Company radio stations, so all the world followed the plight of The Explorer.

Kepner ordered the gondola door opened, as the stricken balloon and crew continued their forced descent past 20,000 feet and finally into air with enough oxygen to support life. The crewmen then donned individual parachutes, in preparation for a possible emergency exit. By this time much of the hydrogen in the torn envelope of the rapidly descending craft had been lost and replaced by outside air, so that almost all that prevented The Explorer from free-fall was the parachute effect of the torn envelope billowing in the slipstream.

Suddenly, at about 4,000 ft above the earth, the entire bottom of the balloon envelope ripped loose and fell away, leaving a huge 125-foot opening at the bottom of the balloon. Kepner, who by now had exited the gondola and was perched on top of the metal sphere, saw that complete failure could occur at any moment. Reluctantly, he ordered the crew to abandon ship.

Bad luck seemed to be the order of the day. Anderson’s parachute pack had inadvertently popped open earlier inside the gondola when the release handle had snagged on something. There were no extra parachutes, so when he heard Kepner’s frantic command to “Shove off, Anderson!”, there was nothing else for him to do but desperately gather the pile of silk lying on the floor of the gondola under one arm and hope for the best. He leaped backward into space away from the gondola and fell toward the earth, praying the disorganized bundle of cloth he held in his arms would become his salvation. As though by divine intervention—and to Anderson’s immense relief—the canopy instantly filled with air, and he floated safely to earth.

At this moment the volatile hydrogen-air mixture remaining in the remnants of the envelope was somehow ignited, and with a boom heard for miles around, the huge balloon exploded into a million pieces. Immediately, the gondola dropped like a stone in a death plunge to the earth below. As the doomed metal sphere and trailing shreds of fabric hurtled downward, only seconds from violent impact with the earth, Stevens became lodged in the tiny opening of the gondola as he tried to exit into the hundred-mile-an-hour slipstream with the bulky parachute pack strapped to his back. Twice he tried to push himself through the hatch of the gondola, but wind pressure around the free-falling sphere forced him back. Kepner, who was still standing on top of the falling gondola, alertly noticed Stevens’ dilemma. He quickly pulled himself into position and gave Stevens a hard push with his foot. Immediately, Stevens fell away from the plunging gondola.

Kepner glimpsed Stevens’ parachute pop open and flash upward past him as he and the gondola continued their plunge to terra firma below. Finally, at the last possible moment, Kepner too hit the silk. His chute barely opened before he landed heavily in a hard, bone-dry Nebraska cornfield only 200 yards away from the remains of the gondola, which lay crushed to bits like an eggshell. He looked up to see Anderson and Stevens, still leisurely floating downward to safety. Within minutes, hundreds of sightseers—many of whom had followed the balloon in their automobiles all the way from the Stratobowl—crowded around the three shaken but unharmed crewmen and the crumpled corpse of The Explorer.

Tragedy had been narrowly averted, but the flight of The Explorer was a failure. No altitude record had been set, and although some useable data and photographs had been salvaged, most of the scientific instruments and the valuable information they recorded had been destroyed when the gondola impacted the hard earth at terminal velocity.

Nevertheless, the three crewmen of The Explorer had performed superbly and displayed uncommon bravery in remaining with the stricken balloon until the last possible moment. In recognition of their “…extraordinary achievement while participating in an aerial flight…,” they were each awarded the Distinguished Flying Cross by the Secretary of War.

Seemingly undaunted by their brush with death and encouraged by their near success, Anderson and Stevens elected to return to the Stratobowl to join the National Geographic Society in preparing for a second high-altitude attempt. For reasons unknown, Kepner did not participate in the second flight.

Some important changes would be made in preparation for the next attempt. To eliminate the possibility of another explosion, the slightly heavier but nonflammable gas, helium, would be used instead of the explosive hydrogen. In addition, a heavier fabric would be utilized for the balloon envelope, to help avoid a rip like the one which occurred on the first flight. To compensate for the increased weight of the heavier fabric and the helium, the number of crewmen was reduced from three to two, and the already unprecedentedly large balloon volume was increased from 3 million to 3.7 million cubic feet. To help finance the second venture, Lloyd’s of London provided a $30,000 payment as partial compensation for the earlier loss of The Explorer.

The new high-altitude balloon, Explorer II, was ready for flight by the summer of 1935, just one year after the initial attempt. Unfortunately, bad luck continued to plague the expedition. On the morning of July 12, the giant envelope ruptured while being inflated and crumpled to the ground, narrowly avoiding injury to ground crewmen below. It was an additional four months before the necessary repairs were made and weather conditions deemed suitable for yet another attempt.

Finally, on November 11, 1935—Armistice Day—Explorer II lifted off from the Stratobowl on the flight which was to establish a world altitude record that would stand unchallenged for the next 21 years. Except for a heart-stopping moment during takeoff, when a vicious downdraft nearly caused the balloon to crash into the rim of the Stratobowl, the flight proceeded according to plan on this final attempt. Anderson and Stevens rode their pressurized gondola up once more into the Stratosphere, but this time there were no unscheduled stops. The giant balloon ascended uninterrupted until the crew and the ton of scientific apparatus they carried with them reached a world record-breaking altitude of 72,395 feet. Anderson and Stevens managed to maintain an altitude of over 70,000 feet for more than an hour and a half, as they recorded data from the 64 scientific instruments, they had brought aloft with them.

People all around the world listened as the fliers communicated with the earth by short wave radio. Stevens and Anderson conversed with crew and newsmen aboard the China Clipper, which was flying just off the coast of California, and they had in-flight interviews with both the National Broadcasting Company in the United States, and a newspaper in London.

Stevens later described the appearance of the earth from almost 14 miles up as a “foreign and lifeless world.” Perched as they were in the top 4% of the earth’s atmosphere, the crewmen aboard Explorer II could not see highways or houses or distinguish any other signs of life. The sky above appeared almost black, and for the first time ever, off on the horizon—an unprecedented 330 miles away—the curvature of the earth could be clearly discerned.

The descent of Explorer II was as smooth and unremarkable as the ascent had been, but with the sudden demise of the original Explorer fresh in their memory, people all over the world held their breaths. One radio announcer conversing with his colleagues over short wave radio cautioned, “Don’t play up this record business, boys, until we are sure they have gotten down safely. There is still plenty of chance for them to crash, and they have to come back alive to make it a record.”

Anderson and Stevens also vividly recalled the sudden ending to their previous flight. As the massive balloon and its precious cargo approached the earth, they prudently donned football helmets they had borrowed from a Rapid City high school and prepared for the worst. But, after a total of 8 hours and 13 minutes aloft, balloon and crew landed safely in a field near White Lake, South Dakota, 230 miles east of the Stratobowl launch site.

Hundreds of people immediately converged on the site, many seeking souvenirs. One woman boldly approached Anderson and asked him for a memento. Seeing that part of the balloon had folded over onto some authentic South Dakota cow chips, the quick-witted Anderson picked one up and said laconically, “Here, lady.” Apparently satisfied, she promptly tucked her “Strato-prize” into her purse.

The impact the record-breaking high-altitude flight had on the world of 1935 was dramatic—approaching that of a modern-day moon flight. A headline-grabbing success story amid the dark, gloomy days of the Great Depression, it inspired more than 3000 pages of newsprint world-wide. Stevens and Anderson, in addition to becoming instant national celebrities, were once more awarded the Distinguished Flying Cross, while the National Geographic Society bestowed upon them its prestigious Hubbard Gold Medal for “…distinction in exploration, discovery, and research.”

The true significance of the flight, however, was more than just the establishment of a world record. According to General of the U.S. Army Air Forces in World War II, H.H. “Hap” Arnold, the Explorer II expedition “…bore fruit in World War II far in advance of what was imagined to be the results at the time.” Technological advances from this expedition that directly benefited U.S. forces in World War II included refinements in the use of strong but light magnesium alloy, an increased understanding of cabin pressurization and two-way radio communication from extreme altitudes, and the development of high-altitude survival equipment, such as electrically heated flying suits. But perhaps the most significant accomplishment of the high-altitude expedition was that it clearly demonstrated man’s ability to survive in the deadly environment of the stratosphere, where future air wars would likely be fought.

The benefits derived from the historic high-altitude flight also extended beyond World War II. The information gained about cosmic rays, the distribution of ozone in the upper atmosphere, the spectra and brightness of sun and sky, and the chemical composition, electrical conductivity and living spore content of the air above 70,000 feet had a direct impact decades later upon the American space program.

The able and talented crewmembers of the two stratospheric flights of 1934-35 went on to distinguished military careers. Both Kepner and Anderson became generals during World War II, while Stevens, who had already achieved considerable renown long before the stratospheric flights, retired from the Army with the rank of Lieutenant Colonel.

The high-altitude manned balloon record established by Explorer II stood for over two decades, but eventually was eclipsed. On November 8, 1956, Navy Lieutenant Commanders Malcolm D. Ross and Morton L. Lewis finally broke the record set by Explorer II when they ascended to 76,000 feet. In May 1961, Commander Ross—this time with Lieutenant Commander Victor A. Prather—further extended the manned balloon altitude mark to almost 114,000 feet, a record which still stands today. As if to once more tragically underscore the dangers involved with exploring this new world, Prather’s life was lost during the ocean recovery attempt following the flight.

Other important lighter-than-air flights have originated from the Stratobowl, since the record-setting stratospheric flights of the 1930s. These include the record-breaking Ross and Lewis flight of 1956, as well as several other flights of note since then. Even today, over 60 years after the first balloon launch from the Stratobowl, its unique attributes still appeal to balloonists. As recently as January of 1996, an around-the-world attempt originated from the Stratobowl. Now privately owned, this historic geological oddity appears almost the same as it did 60 years ago.

Although numerous other record-breaking altitude flights have been made since the stratospheric flights of 1934 and 1935, none accomplished more towards the advancement of science. When Explorer II gently touched down in that dusty South Dakota field on Armistice Day afternoon of 1935, a new footnote to aviation history been written; but more importantly, knowledge had been gained that would help thrust man into his next great frontier, Outer Space.


©2019 by Steve Ruffin's Aviation Hangar. Proudly created with Wix.com