Leonard Nimoy, best known for his portrayal of logic-bound Mr Spock in the Star Trek science fiction television series and movies, died on Friday at age 83 after a battle with chronic obstructive pulmonary disease.
The following are reactions to Nimoy's death.
"Long before being nerdy was cool, there was Leonard Nimoy. Leonard was a lifelong lover of the arts and humanities, a supporter of the sciences, generous with his talent and his time. And of course, Leonard was Spock. Cool, logical, big-eared and level-headed, the centre of Star Trek's optimistic, inclusive vision of humanity's future. I loved Spock," President Barack Obama, whose unemotional approach to problems has been likened to the character Nimoy portrayed on Star Trek.
"RIP Leonard Nimoy. So many of us at NASA were inspired by Star Trek. Boldly go..." the US National Aeronautics and Space Administration (NASA) wrote on Twitter.
"I loved him like a brother. We will all miss his humour, his talent and his capacity to love," William Shatner, who co-starred on Star Trek as Captain Kirk, said in a statement.
"Today, the world lost a great man, and I lost a great friend. We return you now to the stars, Leonard. You taught us to 'Live Long and Prosper,' and you indeed did, friend. I shall miss you in so many, many ways," Star Trek fellow cast member George Takei, who played Hikaru Sulu, wrote on Facebook.
"My heart is broken. I love you profoundly my dear friend. And I will miss you everyday. May flights of angels sing thee to thy rest," actor Zachary Quinto, who portrays Spock in the current Star Trek film series, said on website Instagram.
"He was a true force of strength and his character was that of a champion," Star Trek cast member Nichelle Nichols, who played Lieutenant Uhura, said in a statement. "Leonard's integrity and passion as an actor and devotion to his craft helped transport Star Trek into television history. His vision and heart are bigger than the universe."
"I was lucky to spend many happy hours with Leonard socially and in front of the camera. The calibre and serious commitment of his work on Star Trek was one of the things all of us on Star Trek: The Next Generation sought to match and be inspired by. His work will not be forgotten," Patrick Stewart, who played Captain Jean-Luc Picard on Star Trek: The Next Generation, said in a Facebook post.
"He was a talented actor, director, poet and photographer. But his most enduring quality was his kindness and his desire to make you the most you could be. Like everyone who knew or knew of him, I will miss him," actor Steve Guttenberg, who starred in the Nimoy-directed blockbuster comedy Three Men and a Baby, said in a statement.
"Leonard Nimoy created a positive role model who inspired untold numbers of viewers to learn more about the universe," Space Foundation Chief Executive Officer Elliot Pulham said in a statement. "Many of those people are ardent space supporters and industry leaders today."