This object is on display in the Barron Hilton Pioneers of Flight Gallery exhibition at the National Mall building.
Launched on November 11, 1935, from the Stratobowl near Rapid City, South Dakota, Explorer II carried Captain Albert Stevens, Captain Orvil Anderson, and an assortment of instruments to a world record altitude of 22,066 kilometers (72,395 feet).
Explorer was the brainchild of Captain Stevens, Chief of the Army Air Corps’ photography laboratory at Wright Field, Ohio. With funding from the National Geographic Society, he and two crew members attempted a world altitude-record flight in 1934 with Explorer I. The flight ended in disaster when the balloon ripped shortly after launch, and its hydrogen mixed with air and exploded. After a harrowing few moments while Stevens had trouble escaping through the manhole, he and his two fellow aeronauts parachuted to safety.
For the next attempt, in Explorer II, the portholes were widened for easier escape, and the balloon was filled with helium. To ensure that it attained a record altitude, the balloon was enlarged, the crew was cut from three to two, and its scientific payload was halved.
Like Explorer I, Explorer II was constructed of welded magnesium/aluminum alloy sections. The 2.8 meter (9 foot) sphere weighed 290 kilograms (640 pounds) and carried a payload of 700 kilograms (1,500 pounds). The balloon lifted off at 7:01 am, reached its maximum height of 22 kilometers at 10:50 am and remained there until 12:20 pm. Then it began its descent and touched down at 3:14 pm near White Lake, South Dakota.
One of the flight’s most dramatic successes was the aerial photography: the first photographs showing the division between the troposphere and the stratosphere and the actual curvature of the earth from the record altitude. Captain Stevens’ cameras captured stunning photographs of South Dakota and surrounding states, and demonstrated the potential of high-altitude, long-range reconnaissance from manned balloons.
Although the scientific experiments were reduced from the original plans, Explorer II carried instruments that collected data for studies in cosmic ray research, the ozone layer, aeronomy, meteorology, biology, and radio propagation in the high atmosphere.
The National Geographic Magazine devoted several articles to the flight, widely disseminating the photographic, scientific, and engineering accomplishments to the general public. The flight was a public relations success for the Army and the National Geographic Society, and was also a successful venture between government, military, and civilian scientific interests.
Country of Origin: United States of America
Dimensions: 61 7/16 x 46 7/16 x 46 7/16 in. (156 x 118 x 118 cm)
Materials: Ballast bags-canvas
Physical Description:Ball shape; black & white paint; canvas balast bags; "National Geographic Society & U.S. Army Air Corps" on side.
Inventory number: A19370060000