NASA Commander Mark Kelly on Tuesday announced that he will retire from the space agency after 25 years of service, effective October 1.
In an interview with The Arizona Republic, Kelly also said he will write a memoir with his wife, Rep. Gabrielle Giffords, who was shot in an Arizona shopping center in January.
That tragedy played a role in Kelly's decision. "Gabrielle is working hard every day on her mission of recovery. I want to be by her side," he wrote in a note posted to Facebook. "Stepping aside from my work in the Navy and at NASA will allow me to be with her and with my two daughters."
Giffords was recently released from a Houston-area rehab facility and is staying at Kelly's home in League City, Texas while continuing outpatient therapy. Kelly said he will, therefore, handle most of the writing for their joint memoir. The book will be published by Scribner and will be co-written by Jeffrey Zaslow, who helped pen the memoir for pilot Chesley "Sully" Sullenberger, the Arizona Republic reported.
The announcement comes several weeks after Kelly returned from his final journey to the International Space Station via the shuttle Endeavour. He has been with NASA for 15 years, traveling to the ISS four times, most recently as commander.
"I will be forever grateful to the NASA managers who trusted me with this enormous responsibility during such a difficult period in my personal life and to those leaders in the United States Navy who prepared me to handle these challenging times," Kelly wrote.
NASA's space shuttle program has one final journey to the ISS; Atlantis is scheduled to depart on July 8. After that, the fleet will retire and space exploration will shift to a focus on commercial efforts. Kelly voiced his support for the NASA.
"I know that as our space program evolves, there are those who will question NASA's future. I am not among them," he wrote. "There isn't a group more dedicated to its mission or more capable than the outstanding men and women of NASA. Exploration is a critical component of what makes our country great. We will continue to explore and NASA will continue to lead that effort."