Jan. 21 (UPI) -- NASA astronaut Suni Williams retired from the agency after 27 years of service, including one nine-month stint when she was stranded on the International Space Station. Williams has been "a trailblazer in human spaceflight, shaping the future of exploration through her leadership aboard the space station and paving the way for commercial missions to low Earth orbit," said NASA Administrator Jared Isaacman i n a statement . "Her work advancing science and technology has laid the