Former astronaut Mark Kelly of Arizona was sworn in as a U.S. senator on Wednesday. A Democrat, Kelly reduces the Republican Senate majority to 52-48.

Vice President Mike Pence did the honors, as Kelly’s wife, former Rep. Gabby Giffords, and his identical twin brother and fellow retired astronaut Scott Kelly watched from the gallery.

“Giffords retired from Congress after surviving a 2011 assassination attempt by a gunman,” says the Washington Post. “She and Kelly have since become well-known advocates of gun control.”

Dozens of senators from both parties were also in the chamber for the ceremony.

“Mark Kelly won election last month after defeating GOP Sen. Martha McSally … who was appointed to the seat. President-elect Joe Biden congratulated Kelly on becoming a senator in a tweet,” The Hill reported.

“Kelly will serve the remainder of the late GOP Sen. John McCain’s final two years, and immediately run again for re-election in 2022,” says Politico. “Throughout his Senate campaign against McSally, Kelly proved himself to be a prolific fundraiser.”

Kelly gives Arizona two Democratic senators for the first time in 67 years. The other is Sen. Kyrsten Sinema, who held a Giffords family Bible for Kelly during the swearing-in.

While Sen. Kelly improves the Democrats’ standing, full control of the Senate will be decided by two run-off elections early next month in Georgia. Democrats must win both to gain a 50-50 tie that would be decided by Vice President-elect Kamala Harris if a vote ends in a draw.