US ARMY AIR CORPS & NATL. GEOG. SOCIETY ' EXPLORER 2 ' STRATO-BALLOON NEWS PHOTO
SOCIETY ' EXPLORER 2 ' STRATO-BALLOON NEWS PHOTO. Rapid City. [Explorer II was a crewed U.S. high-altitude balloon Explorer II that was launched on November 11, 1935, and reached a record altitude of 22,066 m (72,395 ft). ].