A Stratospheric Find

A couple of days after our Wind Cave NP excursion, we wanted to take the dogs on a nice hike. So I googled for hiking trails and found one called the Stratobowl Trail. It was about .25 miles from the campground and about 1.7 miles one way. Sounded like a good candidate – easy hike with a view.

The trail used to be a NFS road, so it was wide and gravely with a gradual uphill climb. About a mile up, we saw a side trail to the rim of a cliff.  When we looked to our right we saw a couple of wood split rail fences. While walking over to check out why there was a fence, we caught sight of a large wire enclosure with granite slabs in it. Another item to check out. But first, we continued to the split railings. Turns out they were a protective barrier for an overlook to a huge round,  grassy area in the valley below and some awesome gorgeous views.

Set off to the side was a marker that piqued our interest.

Stratobowl Trail Historic Marker. Rapid City, South Dakota: Copyright © 2018, R. Breiser All Rights Reserved
Stratobowl Trail Historic Marker

Having read the marker we decided to go over and see what the enclosure with the granite slabs was all about. Turns out they told the story behind the Stratobowl Trail Historic Marker. It was an event that took place in 1934-35. Below, I’ve typed the story, as it was written on each of the slab panels, for you to read.

Panel 1

Stratobowl Trail Historic Marker. Rapid City, South Dakota: Copyright © 2018, R. Breiser All Rights Reserved
Stratobowl Trail Historic Marker – Panel 1


Our civilization occupies a large spherical planet which has a diameter of 8,000 miles – therefore a circumference of 24,000 miles. It rotates once every 24 hours and has a velocity of 1,000 miles per hour at the equator.

Surrounding and revolving with the earth is a layer of air (78% Nitrogen, 21% Oxygen, Traces of moisture). Humans can function normally below the 12,000 foot level, but need additional breathing oxygen at higher altitudes.

At altitudes above 38,000 feet, fluids in the body will vaporize unless the body is kept under pressure.

High energy particles from space continually bombard the atmospheric shield above us.

In order to examine and study these phenomena, a large balloon was constructed. It carried a large metal sphere, pressurized with a breathable air mixture. This gondola was a laboratory for scientists.

The region about 13 miles above the earth was selected for the first Explorer ascent. Its partial success provided knowledge that made the Explorer II flight flawless in 1935.

During the 4 ½ mile climb to altitude, the thinning air allowed the balloon envelope to change from a slender, elongated shape to a large round ball. At maximum altitude, the balloon expanded to 192 feet in diameter. (Thirty two feet greater than the width of a football field!)

A large amount of lead shot ballast was carried: To increase the rate of climb; to slow the descent rate; to induce level flight.

Panel 2

Stratobowl Trail Historic Marker. Rapid City, South Dakota: Copyright © 2018, R. Breiser All Rights Reserved
Stratobowl Trail Historic Marker – Panel 2

Thousands of fascinated spectators surrounded these limestone cliffs all night to watch layout, rigging, and inflation of Explorer I by a small army of well trained and dedicated individuals. At sunrise 28 July 1934, the gigantic balloon climbed silently from the bowl.

The project was envisioned and organized by Gilbert Grosvenor, president of the National Geographic Society, in conjunction with the Army Air Corps. Fort Meade Cavalry troopers and the South Dakota National Guard inflated the balloon. Dow Chemical Company, builder of the gondola, and individuals, corporations, and laboratories interested in advancing knowledge participated.

This enormous laboratory weighed six tons. The 3,000,000 cubic foot envelope, fabricated by the Goodyear Zeppelin Company from almost 3 acres of rubber coated cotton, weighed 5,000 pounds. The balance of weight was the gondola, crew, ballast, batteries, scientific equipment, and life-support systems.

As the largest balloon ever built climbed through 15,000 feet, Major William Kepner ordered the hatches closed. Captain Albert Stevens and Lieutenant Orvil Anderson activated life-support systems and deployed and monitored the fantastic array of information-gathering equipment. At 40,000 feet the geiger cosmic ray counter was turned on and began clicking.

At noon more ballast was dropped to increase the rate of climb. One hour later, 11 ½ miles above the earth, a noise was heard and a large rip appeared in the bottom of the envelope. The balloon started downward, gathering momentum. It fell 700 feet per minute at 20,000 feet, then disintegrated at 8,000 feet. Anderson parachuted at 5,000 feet, Stevens at 3,000 feet, and Kepner just 500 feet above the ground. No one was injured.

The spherical gondola created a small crater in a south central Nebraska cornfield, 350 miles from where the flight began ten hours earlier.

Panel 3

Stratobowl Trail Historic Marker. Rapid City, South Dakota: Copyright © 2018, R. Breiser All Rights Reserved
Stratobowl Trail Historic Marker – Panel 3

The malfunction of Explorer I was caused by improper packing of the envelope so it did not unfold complete. As a result, the appendix did not deploy, there was no avenue of release for the hydrogen gas as it expanded and the envelope ruptured. This problem was solved on the next envelope.

Explorer II

Changes in design and operation for Explorer II included the use of helium rather than flammable hydrogen. Since helium is slightly heavier, the volume of the envelope was increased to 3,700,000 cubic feet to maintain the desired floating altitude.

The new spherical gondola was increased to nine feet in diameter to accommodate scientific equipment.

At 7:01 AM on November11, 1935, two United States Army Air Corp Officers – Captain Albert Stevens and Captain Orvil Anderson – lifted off in the giant Explorer II balloon and set out on a flight that would take them into the stratosphere to a height no human being had yet reached – 72,395 feet (13.7 miles).

The trajectory was due east and the balloon stayed airborne for 8 hours and 13 minutes, traveling 255 miles before making an eggshell landing 12 miles south of White Lake, South Dakota. A marker was erected near the landing site on the north side of the road.

Some of the experiments contained in the ton of scientific equipment on board examined cosmic ray energy, ozone distribution, spectra/brightness of the sun and sky, chemical composition, electrical conductivity, and living spore content of the air.

Flight helmets did not exist so the crew borrowed two from the Rapid City High School football team and those helmets exist today.

Panel 4

Stratobowl Trail Historic Marker. Rapid City, South Dakota: Copyright © 2018, R. Breiser All Rights Reserved

Lightweight plastic films, developed in the fifties with funding from the U.S Navy Office of Naval Research, allowed for larger, lighter balloon envelopes. Those for routine unmanned flights gained in size and carried scientific payloads to much higher floating altitudes. Between 1950 and 1960 tremendous advancements occurred, allowing for the following flights.

In September 1959 Dr. Marcel Schein of the University of Chicago used a 6,000,000 cubic foot balloon at a float level of 153,000 feet with a 150 pound scientific payload to investigate antimatter.

In November 1961, Dr. Masatoshi Koshiba of the University of Tokyo utilized a 10,000,000 cubic foot balloon in southern California that floated at 112,000 feet and landed 40 hours later in north California. The 2200 pound scientific payload recorded nature’s atom smashing.


The Navy’s manned Stratolab flights carried a spherical pressurized gondola. On 8 November 1950, Commander Ross and veteran balloonist/scientist Charlie Moore had a telescope mounted on top of the gondola for astrophysical research. Their 2,000,000 cubic foot balloon floated at 82,000 feet.

Hot-Air Balloons

12 November 1960, a U.S. Navy experimental hot-air balloon flown by creator and builder Paul “Ed” Yost made its second free ascension. The flight attained 9,000 feet and lasted two hours.

The Stratobowl was the beginning of the space program and our stumbling upon it made for a very informative and interesting hike. A hike providing views and a history lesson! We never know what we’ll find as we continue our travels but there always seems to be something out of the ordinary.

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