Dennis M. Sesak, who helped develop cruise missile technology at the Johns Hopkins Applied Physics Laboratory, died Monday of multiple myeloma. The Howard County resident was 54.
Mr. Sesak was a gardener and a carpenter who was passionate about conservation and public radio and television. He also was a leading expert on targeting systems for cruise missiles, a fact that came as a complete surprise to his family last week when his former boss escorted them into Mr. Sesak's office.
"He never told them much about what he did," said Mr. Sesak's supervisor, Mike Foust. "I think the phrase he used was, 'I could tell you, but then I would have to shoot you.'"
That wasn't entirely true, Mr. Foust said, but Mr. Sesak was involved in some highly classified work in his 30 years at the lab.
Mr. Sesak, who lived in Howard County, started work at the lab immediately after attending Pennsylvania State University in 1975, where he graduated summa cum laude with a degree in electrical engineering.
Cruise missile technology was in its infancy then -- the weapons were still in the development stage -- and Mr. Sesak was a leader in the development of terrain-aided navigation, Mr. Foust said. That technology uses databases of the variations in the earth's terrain to determine the location of a missile or aircraft, Mr. Foust said.
The technology has advantages over the Global Positioning System because the satellites that run the GPS can be jammed or damaged, but "the Earth is always the Earth," Mr. Foust said. Toward the end of his life, Mr. Sesak was working on new, more advanced terrain-based navigation technology that, in combination with the GPS, would make for a better guidance system, Mr. Foust said.
Mr. Sesak's sister, Geraldine Branca of Bradford, Mass., said the family was proud but surprised to learn how prominent Mr. Sesak was internationally. But the stories she and her siblings have heard since his death testifying to his generosity were no surprise at all.
"I think in terms of who my brother was, he was that kind of person from the Bill Withers song, 'We all need somebody to lean on,'" Ms. Branca said. "Denny was generous that way. ... Everybody has a story about Dennis' generosity."
Mr. Sesak took on the role of primary caregiver for his parents before they died, despite the fact that they still lived in western Pennsylvania, where he grew up. Ms. Branca said she and her siblings have been bombarded with e-mails and phone calls from Sesak's friends in the past week, each with a different story of his generosity.
"What my brother did for these people is kind of amazing," she said.
Mr. Sesak was an athlete who played basketball and coached and played softball. He liked to ride motorcycles and tractors, and didn't like wearing ties, relatives said.
Mr. Sesak's family and friends plan to establish a foundation in his name to support public television and radio. A memorial service is being scheduled for September.
He is survived by another sister, Mary Margaret Sesak of Rockport, Maine; and a brother, John Sesak of Chula Vista, Calif.