Andrew A. "Andy" Dantzler, an optical engineer who was program area manager for civilian space at the Johns Hopkins Applied Physics Laboratory in Laurel, died Thursday of cardiac arrest at Johns Hopkins Hospital.
The longtime Sykesville resident was 49.
The son of a federal government worker and a counselor, Andrew A. Dantzler was born in Bethesda and raised in Rockville, where he graduated in 1980 from Robert E. Peary High School.
After earning a bachelor's degree in astronomy and physics in 1984 from the University of Maryland, College Park, he went to work as an optical engineer at Goddard Space Flight Center in Greenbelt.
From 1984 to 2006, Mr. Dantzler was manager of the Earth Observing System, and Landsat 7 instrument manager. He also was assistant chief of the Laboratory for High Energy Astrophysics, and director of NASA's solar system division at the agency's headquarters in Washington.
In 2005, he became associated with NASA's New Horizons mission to Pluto, whose unmanned spacecraft was scheduled to reach the dwarf planet — 3.7 billion miles from the sun — "about 40 times farther than the earth," after its 2006 launch, reported The Baltimore Sun at the time.
It was NASA's first flight to Pluto and its longest mission ever aboard its fastest spacecraft.
"Pluto is a treasure trove of scientific discoveries waiting to be uncovered," Mr. Dantzler told The Baltimore Sun in 2005.
Since 2006, Mr. Dantzler had been associated with APL's Civilian Space Business Area where he led the Living With A Star Missions, which explored how the sun's high-energy rays and energetic particles can generate hazardous space weather effects near the Earth and affect satellite operations, as well as the Earth's climate.
In 2008, Mr. Dantzler became the first project manager for the Solar Probe Plus program, which after its planned 2018 launch, will take a probe closer to the sun than any previous mission has done.
"We go at night," Mr. Dantzler joked to The Baltimore Sun in a 2008 story, when explaining the $750 million NASA-funded mission, which would be "the first ever to fly scientific instruments through the sun's million-degree corona and to within 4.1 million miles of its roiling surface," observed the newspaper.
"Fifty years ago it was brought up as one of the most important things you could do in heliophysics," Mr. Dantzler told the newspaper. "A hurricane model without the ocean is almost useless."
The Solar Probe and its instruments will allow scientists to study solar storms that "unleash radiation, electrical and magnetic energy on and around Earth that can knock out satellites, threaten humans in space or flying polar air routes, and affect utility grids on the ground," said The Baltimore Sun article.
"I find this to be really exciting. It's going to be a really funny mission," said Mr. Dantzler in the article. "It doesn't even seem possible when you first take a look at it."
He said that the 14-year mission would involve the Solar Probe, which measures 9 feet long and weighs 1,000 pounds, and a shield that would protect its instruments and communications gear from temperatures that could soar to 2,600 degrees Fahrenheit.
Mr. Dantzler was promoted in 2009 to APL's program area manager for civilian space, a job in which he oversaw program management for all civilian space programs at APL, including the Messenger mission, now in orbit about Mercury, New Horizons and the Kuiper Belt.
"Andy's contributions to the program and heliophysics cannot be underestimated," said Ann Garrision Daren, who is managing director of the space department at APL. "He was passionate about Solar Probe Plus, whose mission scientists have waited for years."
Ms. Daren said, "Andrew always lit up a room, and that's why there has been such a major outpouring because of his death. He inspired everyone and meant so much to so many people."
Mr. Dantzler had not retired at his death.
Mr. Dantzler was a third-degree black belt in Judo and was a member of the U.S.A. Judo Association. He was also a nationally certified coach and referee. He also enjoyed traveling.
He was a member of Wesley Freedom United Methodist Church, 961 Johnsville Road, Sykesville, where funeral services will be held at 11 a.m. Wednesday.
Mr. Dantzler is survived by his wife of 17 years, the former Erin E. O'Connor; two sons, Nicholas A. Dantzler and Wesley S. Dantzler, both of Sykesville; a daughter, Melanie M. Celano of Falls Church, Va.; his father and stepmother, Taft and Gladys Dantzler of Blacksburg, Va.; his mother, Barbara Surrett Dantzler of Rockville; two brothers, Stephen Dantzler of Rockville and Mark Dantzler of Damascus; two sisters, Roane Dantzler of Rockville and Kathryn Payne of Harpers Ferry, W.Va.; and many nieces and nephews.