“"The NASA family was sad to learn of the passing of our former friend and colleague Alan Poindexter," NASA wrote in a Facebook post. “"Our thought and hearts are with his family."
Poindexter, 50, was riding jet skis with his two sons in Little Sabine Bay at Pensacola Beach on Sunday when the accident occurred, officials from the Florida Fish and Wildlife Conservation Commission told the Pensacola News Journal.
Poindexter's older son, who is 26, crashed into the jet ski that Poindexter shared with his 22-year-old son, the newspaper reported.
The impact knocked Poindexter off the jet ski. He was pulled from the water and taken to the beach where friends attempted to revive him.
Poindexter was then flown by helicopter to Baptist Hospital where he later died from his injuries, the newspaper reported.
Poindexter's sons were not injured in the accident, which is under investigation.
Poindexter, who went by the nickname "Dex," made two space flights during his career with NASA. In February 2008, he was the pilot aboard the shuttle Atlantis on a mission to deliver the European Space Agency's Columbus laboratory module to the International Space Station.
Poindexter returned to space in April 2010 as commander of the shuttle Discovery on one of the final cargo runs to the station before the shuttles were retired.
“"He was a talented, courageous Navy veteran with gifts," astronaut Greg Johnson wrote on Twitter. "“Dex was a lovable guy with a strong work ethic."
A captain in the U.S. Navy, Poindexter left NASA in December 2010 to become dean of students at the Naval Postgraduate School in Monterey, California. He earned a master of science degree in aeronautical engineering from the school in 1995.
Alan Poindexter was born in 1961 in Pasadena, California, but considered Rockville, Maryland, to be his hometown. He earned a bachelor of aerospace engineering degree from the Georgia Institute of Technology, then was commissioned in the Navy.
Poindexter flew combat missions in Iraq during Operation Desert Storm and Operation Southern Watch, then became a test pilot. He logged more than 4,000 hours flying time in more than 30 types of aircraft.
He was selected to join NASA's astronaut corps in June 1998.
(Editing by Jane Sutton and Eric Beech)