Charles Elachi (born April 18, 1947[1]) is a Lebanese-American professor (emeritus) of electrical engineering and planetary science at the California Institute of Technology (Caltech).

[1] He studied at Collège des Apôtres, Jounieh from 1958 to 1962, and then at the École Orientale, Zahlé, where he graduated in 1964 first in Lebanon in the Lebanese Baccalaureate (Mathématiques Élémentaires).

During the late 1980s and 1990s as the director of Space and Earth Science programs at JPL, Elachi was responsible for the research and development of numerous flight instruments and missions for Solar System exploration, space-based astronomy, and Earth science.

Elachi was elected a member of the National Academy of Engineering (1989) for pioneering developments of space-borne radars for imaging the Earth and planets.

Elachi participated in a number of archeological expeditions in the Egyptian Desert, Arabian Peninsula and Western Chinese Desert in search of old trading routes and buried cities using satellite data, some of which were featured in National Geographic magazine.

He has lectured and given keynote speeches at numerous international conferences and at universities inside and outside the United States, including events in Australia, Austria, Brazil, China, Denmark, Egypt, England, France, Germany, Greece, Holland, China, Japan, India, Ireland, Italy, Kenya, Lebanon, Monaco, Morocco, Singapore and Switzerland.