Alan Poindexter served as commander of space shuttle Discovery in 2010. NASA

Alan Poindexter, a retired space shuttle commander who served in the Navy and flew out of Miramar before joining NASA, died in a personal watercraft accident Sunday near Pensacola Beach, Florida, authorities said. He was 50.

The Florida Fish and Wildlife Conservation Commission said that a personal watercraft Poindexter was riding came to a sudden stop and was rammed by a scooter operated by his 26-year-old son, Zachary. It was unclear why the older Poindexter stopped in the water.

Poindexter uses the exercise bike on the space shuttle Atlantis. NASA
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Poindexter was born in Pasadena but spent part of his childhood in San Diego, graduating from Coronado High School in 1979. Like many astronauts, Poindexter had a lot of experience as a military pilot before he was accepted into the shuttle program. Poindexter graduated from Georgia Tech in 1986 and soon joined the Navy. He was later assigned to Marine Corps Air Station Miramar, where he learned to fly the F-14 Tomcat. He stayed on at Miramar, flying with Fighter Squadron 211 (VF-211). The Navy says he twice deployed to the Persian Gulf, once during Operation Desert Storm and once during Southern Watch.

Poindexter joined NASA in 1998 and served as pilot of the shuttle Atlantis in 2006, delivering the European Columbus Space Laboratory to the International Space Station. He served as commander of shuttle Discovery in April 2010, delivering the Multi-Purpose Logistics Module to space station.

The Associated Press contributed to this story.