George Takei (left) criticized former Star Trek co-star William Shatner as "unfit" for space travel after Shatner became the oldest man in history to fly into space this week.
Shatner, 90, was one of three passengers aboard Amazon boss Jeff Bezos' Blue Origin rocket ship on Wednesday, Oct. 13.
"He's boldly going where other people have gone before," George said to Page Six, repeating the famous line from the opening of the original Star Trek TV series.
"He's a guinea pig, 90 years old...," said Takei, 84. He added that TV's Captain Kirk is "not the fittest specimen of 90 years old".
The two geriatric actors have been feuding for decades. Takei has accused Shatner of dissing him on the set of Star Trek.
In the past, Takei has said Shatner ignored him on the set and changed the script for 1989's Star Trek V, so his character, Hikaru Kato Sulu, would never become a spaceship commander.
In return, Shatner has accused Takei of being a psychopath.
"There's a psychosis there... There must be something else inside George that is festering, and it makes him unhappy that he takes it out on me... Why would he go out of his way to denigrate me? It's sad, I feel nothing but pity for him."
In 2015, George told the The New York Times Magazine that Shatner keeps the feud going to promote his projects:
"Whenever he needs a little publicity for a project, he pumps up the so-called controversy between us."
At the time, Takei mentioned Shatner's outburst against him in 2008, following Takei's wedding to Brad Altman.
"Two months after my wedding, he went on YouTube and ranted and raved about our not sending him an invitation. We had. If he had an issue, he could have easily just phoned us before the wedding, simple as that. But he didn't. And the reason he raised that fuss two months later is because he was premiering his new talk show, Raw Nerve."