Communication satellite pioneer Harold Rosen, ex-W5JKW, of Pacific Palisades, California, died on January 30. He was 90. Inspired by the USSR’s launch of Sputnik I in 1957 that kicked off the space race in earnest, Rosen foresaw the potential for such spacecraft to do more than transmit a beacon signal. An engineer with Hughes Aircraft (later Boeing), he, Thomas Hudspeth, and Don Williams developed a prototype geosynchronous communication satellite, which was called Syncom. NASA launched the first successful spacecraft, Syncom II, in 1963, and President John F. Kennedy spoke through the spacecraft with Nigeria’s prime minister, marking the first conversation between two heads of state via satellite. Syncom III carried images from the summer Olympics in Tokyo in 1964.

A native of New Orleans, Rosen graduated from Tulane University — his academic career interrupted by service in the US Navy during World War II. He went on to earn a Ph.D. in electrical engineering and aeronautics at Caltech. According to Rosen’s brother Ben, Harold Rosen became interested in electronics while in high school, and he built his own radio as a ham radio club project. At some point prior to WW II, Rosen obtained his Amateur Radio license and, according to a close friend from childhood, Stanley Pulitzer, W5JYK, was once regularly active on 40-meter CW. He let his license lapse as his post-war activities accelerated. Pulitzer said Rosen was his Elmer.

Rosen went on to oversee the development of some 150 communication satellites that revolutionized communication worldwide. According to the New York Times, Harold and Ben Rosen founded Rosen Motors, where they developed and manufactured a hybrid electric powertrain. Rosen also started Volacom, an aerospace firm specializing in hybrid propulsion aircraft.

President Ronald Reagan presented Harold Rosen with the National Medal of Technology and Innovation in 1985 for his satellite work, and he was inducted into the National Inventors Hall of Fame in 2003. He also was the recipient of many other honors, including designation as a Distinguished Alumnus by Caltech.