This has been a pretty rough week for "Star Trek" royalty on this 60th anniversary year with the deaths of both Walter Koenig, "Star Trek's" Lt. Pavel Chekov on Sunday, Oct. 25 and Patrick Stewart, the storied sci-fi property's Captain Jean Luc-Picard on Wednesday, Oct. 28. With the passing of Walter Koenig at the age of 90 this past week, franchise luminaries of all degrees are coming out with heartfelt condolences, kind words of remembrance, and tearful reflections. William Shatner, 95, and George Takei, 89, represent the final remaining members of the U.S.S. Enterprise's core crew from "Star Trek: The Original Series" and they both took to social media to express their deep sorrow over losing one of their fellow travelers in the final frontier.Walter Koenig played as Pavel Chekov in six "Star Trek" feature films plus a small role in "Star Trek: Generations." (Image credit: Paramount)"I am deeply saddened to learn of Walter Koenig’s passing," Shatner posted on Instagram."Although we did not know each other well away from the set, we shared the later seasons of the original 'Star Trek' series and the six films that followed. What I observed, and what so many fans have expressed over the years, was a man who genuinely loved the 'Star Trek' community."At conventions, Walter was rarely content to remain behind a signing table. He preferred to be among the people who had kept 'Star Trek' alive for so many decades. That kind of genuine connection is rare, and it will be remembered by everyone who came into contact with him."My condolences to his family, his friends, and the countless fans whose lives he touched."Walter Koenig co-starred in "Star Trek: The Original Series" for two seasons (Image credit: Paramount)George Takei, who portrayed Lt. Hikaru Sulu and co-starred with Koenig on two seasons of "The Original Series" from 1967-69, as well as six subsequent "Star Trek" feature films, offered similar thoughts in memoriam."My heart is heavy. Walter Koenig, our Ensign Pavel Chekov, passed away early today," Takei shared on his Instagram page."Walter and I met on the bridge of the Enterprise in the 1960s, and we stayed friends for nearly six decades. When Brad and I married in 2008, Walter stood beside us as our best man. Just last month, on Sept. 14, he turned 90, on the same day Brad and I celebrated our 18th wedding anniversary. I will always treasure that he and I shared that date."Walter was more than Chekov. He was a writer, a teacher, a thoughtful man, and a loyal friend. To the fans who loved him for so many years, thank you. He loved you too. "Rest well, my dear friend. Keep navigating a steady course."