Historical photo of Jackson Roykirk
Jackson Roykirk was an early-21st century Earth scientist who was largely credited for the creation of the Nomad space probe – an artificially-intelligent machine sent out with the mission to seek out new life in 2002. Roykirk's ambition was to build a perfect thinking machine capable of independent logic. Spock described him as one of the most brilliant but erratic scientists of his time. (TOS: "The Changeling")
Background
The photographic image of Roykirk seen in "The Changeling" was "portrayed" by director Marc Daniels. Although he was a 21st century scientist, he wore a standard 2260s Starfleet dress uniform in the photo (albeit it seems to be either a reversed image or configured slightly differently based on the opposite positioning of the "decorations").
According to the Star Trek Spaceflight Chronology, Roykirk died in 2022.
In an homage to Star Trek, a character named "Jackson Roykirk" appeared in an episode of Team Knight Rider entitled "Apocalypse Maybe," played by William Christopher of M*A*S*H fame. While this may seem to be a crossover, constant references to "Star Trek" on the show make it unlikely. [1]
Apocrypha
Jackson Roykirk is mentioned in The Rise and Fall of Khan Noonien Singh, Volume 2 as being part of the team which designed and created the Template:ShipClass ship which carried Khan and his remaining followers to the stars.