Simon Ramo had recently left Howard Hughes’ fledgling Hughes Aircraft Co. to launch his own aerospace firm out of a former barbershop in Westchester when the call came from President Eisenhower. The president told the young scientist that the country needed to develop a rocket capable of delivering a nuclear warhead to the other side of the globe in less than an hour. Within three years, Ramo oversaw work on the program and successfully launched a Thor missile that flew 1,300 miles downrange from Cape Canaveral, Fla. Ramo, the chief architect of America’s intercontinental ballistic missile system and an aerospace pioneer who helped shape Southern California into the nation’s center for high-tech weapons research, died Monday of natural causes in his sleep at his home in Santa Monica, said his son, Jim Ramo. He was 103. Ramo was a Caltech whiz kid who co-founded aerospace giant TRW Inc., and in his late 80s, brokered one of the biggest mergers ever in the defense industry. Often called the “R” in TRW or just “Si” to friends and family, Ramo helped transform the region’s aerospace industry from metal-bending aircraft manufacturing to the world’s epicenter for sophisticated weapons...