"Richard was in good spirits when I visited him 2 weeks ago. He knew his time was short, but was comforted by the fact that his son would be taken care of," Alec Peters, the writer-producer behind the Star Trek fan film Axanar, wrote on Facebook. Hatch had acted in and was a supporter of the project, playing a Klingon in Prelude to Axanar.

Ronald D. Moore, creator of the Battlestar Galactica reboot, tweeted: "Richard Hatch was a good man, a gracious man, and a consummate professional. His passing is a heavy blow to the entire BSG family."

On the original Battlestar Galactica , which ran for the 1978-79 season, Hatch played hotshot pilot Captain Apollo, with the role earning him a Golden Globe nomination for best actor in a television series, drama. In the 2004-09 reboot, the actor returned to the franchise as Tom Zarek , an opportunistic political leader who often shook up the playing field as humanity tried to survive annihilation at the hands of the Cylons , a cybernetic race who rebelled against their creators.

Hatch also starred as police Inspector Dan Robbins opposite Karl Malden in the fifth and final season (1976-77) of the ABC drama The Streets of San Francisco. He effectively replaced Michael Douglas, who exited the show (Douglas' character Steve Keller left the force to become a professor of criminology).

"It was hard because Michael Douglas was like a second son to Karl Malden, who was respectful to me, but never warm and welcoming like Lorne Greene on Battlestar Galactica," Hatch said in a 2012 interview. "Even my girlfriend at the time liked Michael Douglas and missed the Steve Keller character."

Hatch also played Philip Brent, who was drafted into the Vietnam War, in the original cast of the ABC daytime soap opera All My Children. Other credits included episodes of Hawaii Five-O (1973-75) and The Waltons (1974-75).

Hatch was born May 21, 1945, in Santa Monica and began his career acting Off Broadway. Throughout his life, Hatch maintained a passion for Battlestar Galactica, penning three novels continuing the adventures from the original series. In 1999, before the rebooted show got off the ground, Hatch pitched Battlestar: The Second Coming as a possible revival to the series, producing a trailer for a pilot, though the project did not move forward. Instead, Moore's now-classic series got the green light.

"When you meet someone with a vision, you have to give them a shot and an opportunity to see what they can do," Hatch said in 2009 of joining Moore's show as the revolutionary Zarek. "I felt it was worth taking a shot with someone this gifted and someone who I felt really loved science fiction and appreciated the genre."

Hatch also became a fixture on the fan convention circuit, hosting Battlestar Galactica panels at San Diego Comic-Con and Dragoncon.

"In my case, Battlestar Galactica was a milestone. It afforded me the opportunity to live out my childhood dreams and fantasies," the actor once said. "Hurtling through space with reckless abandon, playing the dashing hero, battling Cylons, monsters and supervillains — what more could a man want?"

Edward James Olmos, Hatch's co-star on the BSG reboot, on Tuesday tweeted this tribute: "Richard Hatch you made our universe a better place We love you for it. Rest In Peace my friend @SoSayWeAll the Admiral!"

Hatch is survived by his son, Paul.