Biography: Hayley Arceneaux is an American physician assistant and commercial astronaut who joined SpaceX’s Inspiration4 mission in 2021. She became the first person in space with a prosthetic leg and the youngest American to orbit Earth. A cancer survivor, Arceneaux works at St. Jude Children’s Research Hospital and was inspired by her own treatment there. She also climbed Mount Rainier as part of her spaceflight training.