Mark Kelly, a former astronaut and husband of former Rep. Gabrielle Giffords, was sworn in as a U.S. senator on Wednesday afternoon.
Kelly, a Democrat, defeated Sen. Martha McSally in a November special election. McSally had been appointed by Gov. Doug Ducey to serve in the seat once occupied by Sen. John McCain, who died in 2018.
Because Kelly was elected in a special election, he is being sworn in ahead of newly-elected Senators, who will assume their roles early next year.
Kelly's seat is one of three Democrats flipped on election day, while Republicans were able to flip one seat back into their control. Control of the chamber remains dependant on the outcome of two runoff elections in Georgia, which will take place in January.
During his NASA career, Kelly flew four missions to space and totaled more than 54 days outside of the Earth's atmosphere. His twin brother, Scott, is also an astronaut.
Kelly's first foray into politics came via his wife. Giffords was first elected as a congresswoman in 2006, but in 2011, a gunman shot her in the head during an assassination attempt. She survived the shooting but resigned her seat in early 2012 to focus on the recovery.
Kelly is at least the second former astronaut to serve in the U.S. Senate, following in the footsteps of John Glenn, who was the first man to orbit the earth and served as a senator representing Ohio from 1974 to 1999.