Shannon Walker is an American physicist and a NASA astronaut selected in 2004. She launched on her first mission into space on June 25, 2010 onboard Soyuz TMA-19 and spent over 163 days in space.
She returned to space for her second long duration mission on November 15, 2020, onboard SpaceX Crew-1, the first operational flight of SpaceX's Crew Dragon spacecraft.