Osoaviakhim-1

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.

As it descended past the 12,000 metres (39,000 ft) mark, cooling down to ambient air temperature, a rapid loss of buoyancy caused a downward acceleration that triggered the structural failure of the suspension cables.

Andrey Vasenko, an engineer from the Institute of Aerial Photography in Leningrad, and a future crewmember of Osoaviakhim-1, designed his version of Piccard's balloon in 1930, however, Osoaviakhim delayed funding until the end of 1932.

The Osoaviakhim program, in particular, was sponsored and consulted by Abram Ioffe of the Physical-Technical Institute; one of his postgraduate students, Ilya Usyskin, joined the crew of Osoaviakhim-1 and perished on its fatal flight.

[3] The commissioners emphasized that the crew, although equipped with personal parachutes, had little chance of bailing out in case of emergency: the sole airtight hatch was held in place with twelve wing nuts.

[4][7] The crew did not wear pressure suits (which simply did not exist at that time) or individual breathing sets, relying on stored supplies of compressed oxygen and carbon dioxide absorber cartridges.

[4][7] Osoaviakhim-1 had a crew of three men: Maiden flight of Osoaviakhim-1 and USSR-1 was planned on September 30, 1933 from the same Air Forces airfield in Kuntsevo (earlier, USSR-1 failed to lift off due to a "heavy load of moisture").

[3] January 9, 1934 Defence Commissar Kliment Voroshilov requested Stalin's approval of the winter launch, specifically noting that it would be kept secret until the altitude record was set.

[7] Weighing on the morning of the launch day, January 30, demonstrated that the aircraft still possessed a reserve in buoyancy, and the crew decided to increase ballast weight by 180 kilograms, which would enable them to reach 20,500 metres altitude, higher than initial estimates.

Further ascent and inevitable loss of hydrogen made this ballast insufficient; the only escape route was through bailing out on personal parachutes, provided that the crew could open the awkward hatch.

[3][7] At 12:45 the crew opened the gas release valve for three minutes to initiate descent; the hot balloon did not respond as planned and travel to 18,000 metres took more than two hours.

At about 2,000 meters the gondola separated from the balloon and impacted the ground between 16:21 and 16:23, near Potizh-Ostrov village in rural Insarsky District of Mordovia, 470 kilometres east from the launch site.

[19] 23 hours after the impact, Avel Enukidze announced the accident from the rostrum of the Communist Party congress; immediately after his brief statement Pavel Postyshev proposed burying the crew in Kremlin Wall Necropolis.

[21] Western press followed suit;[22] Time magazine, although incorrectly reporting that "there was not enough left of the crushed gondola or the three broken bodies to supply the story of the tragedy", correctly guessed the roots of the catastrophe: "winter weather had contracted the balloon's gas to such a point that it fell like a dead weight".

[21] The funeral of the crew (February 2) turned a disaster into a propaganda campaign; the three victims were posthumously awarded the Order of Lenin and their ashes buried with state honours in the Kremlin Wall Necropolis.

Potizh-Ostrov, the village near the crash site, was renamed to Usyskino; across the country, streets and squares were named after individual crewmembers or collectively, like Proezd Stratonavtov in Tushino (now a district of Moscow).

[19] They acknowledged that the crew died of high speed impact at 16:21 Moscow time; the flight logs, found intact, revealed that the crewmembers were unaware of imminent catastrophe until 16:10, when the balloon descended to 12,000 meters.

Airspeed beyond design limits snapped the suspension cables and tore open the envelope; eventually the gondola completely separated from the falling balloon.

[19] On February 5, a state commission chaired by General Staff deputy chief Mezheninov issued a detailed report that, regardless of later findings and clarifications, provided a stable version of the accident and its causes; the time of impact was changed to 16:23.

Airtightness and life support systems were in order until the moment of catastrophic fall, as indicated by barometric recorder and Vasenko's log entries ending at 16:13.

[7] In March the investigators' reports were released to the general public, including the final verdict blaming the catastrophe on the crew's "recklessness in rise for record".

Voroshilov summarized his understanding of the investigators' reports in a February 19 note to Stalin: "... despite lack of proper management during construction and pre-flight preparation, the flight itself was technically feasible up to 20,500 meter altitude.

USSR-1 on a 1933 postage stamp . Here the balloon is shown in low altitude configuration; in the stratosphere the envelope expanded into a nearly perfect sphere .
Fedoseenko, Vasenko, Usyskin on 1934 postage stamps. A similar set in different colors was issued in 1944.
Launch preparations
Osoaviakhim-1 crew boarding the fatal flight. Note the rope basket woven around the gondola.
Osoaviakhim-1 flight profile according to Mezheninov's report [ 7 ]