Overview of the Explorer I Mission
commemorated by this plaque '
(AI written from 5 sources):
Explorer I Balloon Flight — July 28, 1934
On July 28, 1934, the United States launched the Explorer I balloon,
a high-altitude, hydrogen-filled craft designed to carry
three passengers into the stratosphere. The mission was a joint
effort between the National Geographic Society and the U.S. Army Air Corps.
Crew and Mission
The flight crew consisted of:
Major William E. Kepner – flight commander
Captain Albert W. Stevens – scientific observer
Captain Orvil A. Anderson – pilot
All three pilots received the Distinguished Flying Cross
for their participation in this flight.
They launched from a specially prepared “natural bowl”
site near Rapid City, South Dakota, known as the Stratobowl,
chosen for its natural protection from wind and ideal launch geometry.
Launch and Ascent
The balloon, a 3-million-cubic-foot hydrogen-filled envelope,
lifted off at 5:45 a.m. (some sources note 6:45 a.m. for radio broadcast time).
The ascent was watched by thousands, with the event broadcast live
on radio and attended by about 30,000 spectators.
Altitude and Crisis
After about seven hours, the balloon reached 60,613 feet. At this height,
tears appeared in the hydrogen gas bag, causing rapid gas loss.
The crew decided to descend. As the balloon dropped, it encountered
strong winds and vertical speed, leading to a burst at around 3,000 feet.
Descent and Rescue
The gondola plunged toward the ground, but the crew parachuted to safety.
Accounts differ slightly on whether the parachute was deployed
before or after the hydrogen explosion, but all three survived uninjured.
Kepner bailed out at barely 500 feet in one account, while others note
they escaped before the explosion.
Significance
Although the flight missed the world altitude record by about 624 feet,
it was a major milestone in high-altitude balloon science.
The mission tested navigation instruments and gathered valuable
data on atmospheric conditions. All three crew members later
received the Distinguished Flying Cross for their bravery.
The Explorer I flight is remembered as both a technical achievement and
a daring survival story, paving the way for later high-altitude scientific
missions like Explorer II in 1935.
Explorer II set the world altitude record Explorer I failed to achieve.