Hong came by his interest in science naturally. He was born in 1971 on the exclusive Palos Verdes Peninsula, outside Los Angeles, and his father, Yong Shik Hong, worked as an aerospace engineer at the federally funded Aerospace Corp. The family returned to Seoul in 1974 so the elder Hong could lead South Korea’s short-range missile program, at the bidding of then-President Park Chung Hee.

Korean fathers of that era were strict and remote. Hong’s father was engaged and intellectually indulgent. He installed a work bench in Dennis’s room when he was 4, complete with a hammer and saw. He led the children in chemistry experiments and brought home model airplanes from America.

Dennis Hong built things with scraps of wood and metal and bits of plastic. He disassembled toys and stored the parts in a chest beneath his bed.

“We spent a lot of time building things and breaking things,” said Julie Hong, Hong’s older sister. “He was the one who broke things the most and built things the most.”
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Hong traveled to America to complete his university study, following his father’s credo, “Big fish must swim in the big sea.” He earned a bachelor’s in mechanical engineering at the University of Wisconsin and a master’s and doctorate at Purdue.