Syncom designer Harold Rosen passes away

While Arthur C. Clarke came up with the theory of using satellites for communications in a geosynchronous/geostationary position in 1945, actually it was spacecraft designer Harold Rosen who made it a practical reality. As such it is sad to report that spacecraft designer Harold Rosen who was the leader of the team that built the first practical geosynchronous comsat series, Syncom, has died at the age of 90.

Rosen was originally an electrical engineer having gained Bachelors of Science degree at Tulane University, and a Masters and PhD at Caltech. After working at Raytheon on surface-to-air missiles, Rosen moved to Hughes in 1956.

In his time at Hughes, Harold Rosen led the team that created the first practical GEO communications satellite called Syncom. After Syncom I was lost after its Apogee Kick Motor (AKM) failure in February 1963, Syncom II was successfully launched in August 1963. It was followed by Syncom III in 1964 which was the first satellite to relay live television signals from Tokyo during the Summer Olympics.

Syncom II Courtesy: wikipedia

Syncom II Courtesy: wikipedia

The Syncom series of spin stabilised satellites were followed by other spinner designs culminating with the HS-376 series.

“Spinners”, which are often somewhat unfairly dubbed  “flying trash cans”, have now been mainly replaced by 3-axis designs for communications satellite use. Nevertheless, some weather satellites still use the concept.

Harold Rosen was predeceased by his wife Rosetta in 1969, but leaves two sons. We give our tribute to this most excellent space engineer and our sympathies to his family and friends.


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