Andrew A. Dantzler, a former senior NASA official who joined the Johns Hopkins University Applied Physics Laboratory (APL) in 2006 where he led the lab’s civil space programs, died Oct. 13, according to a death notice published in The Washington Post. The 49-year-old space scientist died of cardiac arrest, according to a colleague.

Dantzler worked at NASA from 1984 to 2006, serving as an optical engineer, Earth Observing System manager, Landsat 7 manager and director of solar system exploration at the agency’s Washington headquarters. In 2006, he joined APL to lead the Laurel, Md.-based lab’s Living with a Star missions. Dantzler also served as the first program manager for the Solar Probe Plus mission, which is still in development. In 2009, Dantzler was promoted to program area manager for civilian space, a job that put him in charge of overseeing APL’s various space science missions, including the Messenger probe currently orbiting Mercury and the New Horizons probe en route to Pluto.

Dantzler is survived by his parents, wife Barbara, daughter Melanie Celano and sons Nicholas and Wesley, two brothers and a sister.