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How tall is Alexander Gerst?
Short answer
ESA does not publish its astronauts' height, including Alexander Gerst's; any figure circulating online has no official source. What is documented: born 3 February 1976 in Künzelsau, geophysicist, ESA astronaut since 2009, with two long-duration ISS missions in 2014 and 2018.

What the official biography says
ESA's astronaut biographies include date and place of birth, education, year of selection and missions; height and weight are not among that data. For Alexander Gerst it states the following: born on 3 February 1976 in Künzelsau, he studied geophysics, carried out fieldwork on active volcanoes and joined the European astronaut corps in 2009. The height figures circulating online do not come from the agency, so we do not reproduce them here.
Why body measurements do matter
In spaceflight, measurements are no small detail: the individual seats of the Soyuz capsule are custom-fitted to each occupant, pressure suits only exist in a few sizes, and selection processes impose minimum and maximum height limits, because otherwise the rescue systems would not fit. There is also an effect that puts any figure into perspective: in weightlessness the spine stretches, so astronauts are measurably taller in orbit than on the ground, and shrink back after landing.
Two long-duration flights and a command
Gerst's first flight, the Blue Dot mission, began on 28 May 2014 aboard a Soyuz and ended on 10 November 2014; it included a spacewalk. His second stay, Horizons, launched on 6 June 2018 and ended with landing on 20 December 2018. During the second half of this mission, Gerst became the first German to command the International Space Station. Both missions were prepared over years in Cologne, Houston, Star City and Tsukuba: training in which body measurements do play a role, even if they need not be made public.
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