HUNTSVILLE, Ala. (AP) — Each year around this time, NASA honors fallen astronauts, including the 17 men and women killed in three separate wintertime accidents in the sky and on the earth.

For Robert "Hoot" Gibson, it's a time to remember lost friends and some of their stunts, like playing a saxophone in orbit.

Gibson, who flew on five space shuttle missions, knew each of the 14 astronauts who died in the Challenger explosion on Jan. 28, 1986, and in the Columbia disaster on Feb. 1, 2003.

On Thursday, he lit a candle of remembrance during a ceremony at NASA's Marshall Space Flight Center. Behind him hung a photo of astronauts including Ron McNair.

Gibson and McNair were crewmates aboard Challenger during a mission in February 1984. McNair, a black belt in karate who also played jazz saxophone, serenaded the crew with music.

"He played 'What the World Needs Now is Love,' and we put together a video," Gibson said in an interview.

The memorial came a day after the 29th anniversary of the Challenger explosion, in which McNair and six other astronauts died. Seven astronauts were killed aboard Columbia, and three died during ground testing of Apollo 1 in January 1967.

The memorial also honored another 40 one-time astronauts have died of various causes since NASA began.

Gibson left NASA in 1996 after post-flight work that included serving as chief astronaut. Now 68, the one-time Navy fight pilot lives in Murfreesboro, Tennessee.

Gibson feels fortunate to have flown in space, and he still remembers those who didn't make it back.

"You think about the contributions that those people made, and all the wonderful things they did and all the wonderful things that they were going to do in the future," he said.