Umberto Guidoni and Reinhold Ewald, are physicists and, which other occupation?
Umberto Guidoni: Umberto Guidoni (born in Rome 18 August 1954) is an Italian astrophysicist, science writer and a former ESA astronaut, being the first European to visit the International Space Station. Reinhold Ewald: Dr. Reinhold Ewald (born December 18, 1956) is a German physicist and ESA astronaut.
astronaut