(written from a Production point of view)
Robert Phillips (10 April 1925 – 5 November 2018; age 93) was an actor who portrayed the illusory space officer seen in the Star Trek: The Original Series episode "The Cage" and later, via re-used footage, in the first season episode "The Menagerie, Part II". He filmed his scenes for "The Cage" on Friday 4 December 1964 at Desilu Culver Stage 15. He received no credit for his appearances.
Phillips was a former policeman turned actor and also appeared in the film Hour of the Gun (1967, with Steve Ihnat, William Windom, William Schallert, Monte Markham, and Dave Perna; music by Jerry Goldsmith) and in the television movie Mitchell (1975, with Jerry Hardin).
Phillips died on 5 November 2018. (Screen Actors Guild Magazine, Special Edition 2019, p. 96)