Осоавиахим-1

Osoaviakhim-1 was a record-setting, hydrogen-filled Soviet high-altitude balloon designed to seat a crew of three and perform scientific studies of the Earth's stratosphere. On January 30, 1934, on its maiden flight, which lasted over 7 hours, the balloon reached an altitude of . During the descent, the balloon lost its buoyancy and plunged into an uncontrolled fall, disintegrating in the lower atmosphere. The three crew members, probably incapacitated by high g-forces in a rapidly rotating gondola, failed to bail out and were killed by the high-speed ground impact.