Auguste Piccard and Paul Kipfer in 1931.

Credit - ") 2001 National Air and Space Museum, Smithsonian Institution (SI Neg. No A-31620-D)"

Second flight of the Century of Progress

Credit - ") 2001 National Air and Space Museum, Smithsonian Institution (SI Neg. No. 75-15326)"

First flight of the Century of Progress.

Credit - ") 2001 National Air and Space Museum, Smithsonian Institution (SI Neg. No. 88-13377)"

"Explorer I ascent to 60,613 feet."

Credit - U.S. Air Force

"Kepner, Stevens, and Anderson."

Credit - U.S. Air Force

Captain Hawthorne Gray.

Credit - U.S. Air Force

Balloon basket and equipment used by Capt. Gray

Credit - U.S. Air Force

Explorer I falling after gas bag ruptured.

Credit - U.S. Air Force

Section of Explorer I gondola

Credit - U.S. Air Force