Mark T. Vande Hei is an American astronaut and retired U.S. Army officer. He was born on October 10, 1966, in Falls Church, Virginia. Vande Hei earned a Bachelor of Science degree in Physics from Saint John's University and a Master of Science degree in Applied Physics from George Washington University. He was selected as a NASA astronaut in 2000. Vande Hei has completed multiple missions to the International Space Station (ISS), where he conducted scientific research and technology demonstrations. Notably, he holds the record for the longest continuous stay in space by a NASA astronaut, spending 355 days aboard the ISS from 2021 to 2022.