Mark Edward Kelly is an American politician, retired astronaut, and former naval officer who has served as the senior United States senator from Arizona, a seat he has held since 2020. He is a member of the Democratic Party. Kelly flew combat missions during the Gulf War as a naval aviator before being selected as a NASA Space Shuttle pilot in 1996. He flew his first space mission in 2001 as pilot of STS-108, then piloted STS-121 in 2006, and commanded STS-124 in 2008 and STS-134 in 2011.