July 27, 1962: First cosmonaut zero-gravity training flight takes off

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On July 27, 1962, two Russian cosmonauts boarded a Soviet airliner and experienced weightlessness without going to space. This was the first time cosmonauts completed zero-G training on an airplane.

The Tupolev Tu-104 was a type of jetliner originally designed to transport 50 passengers. It was modified to accommodate cosmonauts who needed to train in an environment that simulated weightlessness. By flying in a parabolic arc, passengers could experience 6 to 25 seconds of weightlessness on each maneuver.

Cosmonauts Andriyan Nikolayev and Pavel Popovich were on this flight to prepare for their upcoming orbital missions Vostok 3 and Vostok 4 .

The Soviet Union used a modifed version of a Tupolev Tu-104 commercial jetliner like this one to make the first cosmonaut zero gravity training flight in 1962, (Image credit: Lars Söderström / Shutterstock/ Russia in Space Exhibition (Airport of Frankfurt, Germany 2002)) Why it mattered

Human spaceflight was barely a year old in July 1962, so methods of training cosmonauts (and astronauts) were still in development. In the early days of the Space Age, the effects of weightlessness on the human body — including basic functions like eating and using the bathroom — were still being understood, so the more realistic training could be the better.

For Nikilayev and Popovich, this training was vital. Their Vostok 3 and Vostok 4 missions flew at the same time, marking the first-ever dual spacefligth of two crewed craft (they were single-person capsules). Vostok 2 lasted nearly four days — something NASA would not beat until the Gemini program in 1965 — while Vostok 4 was a nearly three-day flight. The two spacecraft flew within 4 miles of each other during their missions.

Today, NASA and Russia's Federal Space Agency ( Roscosmos ) still train astronauts and cosmonauts on modified jets that simulate weightlessness by flying parbolic flights. You can even buy a ticket to try it yourself through commercial companies like Zero Gravity Corporation , which also flies science flights for NASA.

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