George Leonard Tyler, 1940–2023

George Leonard Tyler

Credit: Stanford University.

George Leonard (Len) Tyler, professor of electrical engineering at Stanford University and leader of numerous studies of the planets of the solar system, passed away in Port Townsend, Washington, at the age of 82. The cause was late-stage Alzheimer’s disease.

Tyler was best known for pioneering and perfecting the science of radio occultation, where radio signals pass through planetary atmospheres and bounce off the harder surfaces below to map the underlying structures. In 1968, as a young research assistant, Tyler first appeared in a Stanford News report about his studies of the soil on the surface of the Moon. In subsequent years, working through NASA’s Jet Propulsion Laboratory, Tyler would lead successful studies of Mars, the rings of Jupiter and Saturn, and the structure of Neptune, among other explorations of Earth’s solar system siblings.

“He was the premier expert in radio science for several decades — the person NASA chose to lead radio exploration of the planets and moons,” said Howard Zebker, professor of electrical engineering and of geophysics, a one-time advisee, and later colleague of Tyler’s at Stanford.

As a leader in the specialized field of radio science, Tyler explored each of the main bodies in the solar system, the last being Pluto as Principal Investigator (PI) during development of the Radio Science Experiment (REX) on New Horizons. During his career, he also investigated radio wave scattering from Earth’s ocean surfaces and was a PI or Co-I on the Viking, Voyager, Magellan, Mars Global Surveyor, and Mars Express missions. Former colleagues noted that Tyler joked that he had “visited every planet in the solar system” and “never met an asteroid that he didn’t like.” In fact, asteroid 195405 was permanently assigned his name in recognition of his contributions to the study of Pluto and the Kuiper belt.

More information about Tyler’s life and legacy is available at

— Text courtesy of Stanford University