Legendary sci-fi actor Leonard Nimoy, once referred to by Gene Roddenberry as "the conscience of 'Star Trek'," has passed this morning at his home in Los Angeles. He was 83.

According to The New York Times, the actor's wife Susan Bay Nimoy attributed his death to end-stage chronic obstructive pulmonary disease. Nimoy, who had been rushed to the hospital late last week with severe chest pains, revealed last year he suffered from COPD, developed from years of smoking decades ago.

A director, poet, singer and photographer, Nimoy is of course best remembered for playing Spock on the 1966-1969 series "Star Trek," a role he'd reprise on "Star Trek: The Animated Series," two episodes of "Star Trek: The Next Generation," and eight movies, including J.J. Abrams' 2009 franchise reboot and its 2013 sequel.

However, Nimoy's acting career was by no means restricted to one genre. Before "Star Trek" he, like most actors of the era, had minor roles on Westerns like "Gunsmoke," "Wagon Train" and "Bonanza," and afterward, he landed a starring role on "Mission: Impossible." Later, he famously hosted "In Search of ..."

In recent years, long after the original cast seemed to have bid farewell to the Enterprise in the 1991 film "Star Trek VI: The Undiscovered Country," Nimoy like his former co-stars William Shatner and George Takei underwent a career resurgence. In addition to his appearances as Spock in the most recent "Star Trek" films, Nimoy had a recurring role on the sci-drama "Fringe," and voiced Sentinel Prime in "Transformers: Dark of the Moon."