Born in Brooklyn, N.Y., Mike received an S.B. in industrial engineering from M.I.T. in 1951. He worked briefly in the aircraft industry and received an M.S., also in industrial engineering, from Case Institute of Technology in 1953.
Mike served as an officer in the U.S. Navy from 1954 to 1958. During the first part of his service he was stationed in New Mexico, where he developed and taught nuclear weapons technology. Later he was stationed at the Naval Research Laboratory in Washington, D.C., where he worked on Project Vanguard. He led an investigation that used the orbital precession of the Vanguard 1 satellite to establish one of the earliest determinations of the coefficient of the second harmonic of Earth's gravitational potential.
After his discharge from the Navy, Mike embarked upon doctoral studies in astronomy at Yale, at the invitation of Dirk Brouwer. He finished his Ph.D. in 1963, having carried out some of the earliest computer modeling of stellar atmospheres. While still a graduate student, Mike joined, as one of the founding members, the NASA Goddard Institute for Space Studies at Columbia University in 1962.
At the invitation of Fred Whipple, Mike moved to the Smithsonian Astrophysical Observatory in 1965. He remained with SAO until his retirement, as a Senior Astrophysicist, in 2009. He had been a member of both the Planetary Sciences Division and the Theoretical Astrophysics Division. Mike's research interests included gravitational dynamics, planet formation, and the dynamics of our solar system. During his career he authored or co-authored more than 90 scientific articles. Among those is a series of elegant papers, written with Fred Franklin and Marc Murison, establishing a relation between the time scales of dynamical chaos and long-term stability in the solar system. Another article, written with Paul Gorenstein and Daniel Fabricant, was selected as one of the fundamental papers published in the 20th century in the Astronomical Journal and Astrophysical Journal, and reprinted in the AAS Centennial Issue, 1999. Asteroid (4417) Lecar is named in Mike's honor.
Among his many accomplishments, Mike was particularly proud of his role in establishing the first astronomical observatory in Israel. Mike was the PI of a grant from the Smithsonian Institution to provide the astronomical instrumentation. He spent a significant amount of time in Israel during the planning, construction, and commissioning of the observatory. The Wise Observatory, located in the Negev desert, was dedicated in 1972 and is still operational today. It remains the primary astronomical observatory in Israel, yielding a steady stream of scientific results on a variety of topics.
Always with an eye to the future, Mike was a founding member of Harvard University's 'Origins of Life Initiative,' led by Dimitar Sasselov.
Mike cherished his role as teacher and mentor. He introduced many students to the life of science through Harvard's Freshman Seminar Program. He taught annual, highly interactive courses on cosmology and planet formation, painstakingly refining his presentations to make important key concepts accessible to novices. He served as thesis advisor for a number of graduate students, including William Wiesel, Larry Liebovitch, and Carlton Pryor. He guided a number of junior colleagues through the pitfalls of their early careers. He offered wise, sensible counsel to the Observatory's senior members.
Mike's interests outside of astronomy included travel, with frequent destinations including England, Israel, and the beaches of Cape Cod; reading, emphasizing geopolitics, fiction, and the sciences; and participation in the Jewish community in the Cambridge and Boston area.
Mike lost his wife, Rosemary Johnson, in 2005. They had shared their lives for 27 years. Mike is survived by his brother, Harold Lecar, sister-in-law, Helene Lecar, and nephews Matthew and Joshua Lecar.