Do check out this study - NASA lucked out in having twin astronauts, one of whom spent nearly a year on the ISS while his brother stayed on Earth. https://www.

Do check out this study - NASA lucked out in having twin astronauts, one of whom spent nearly a year on the ISS while his brother stayed on Earth. https://www.nasa.gov/humans-in-space/twins-study/ https://www.nasa.gov/humans-in-space/twins-study/