In Star Trek: The Motion Picture (1979), V’Ger was an immense alien spacecraft that threatened Earth.
V’Ger turned out to be evolved form of Voyager 6, a fictional unmanned probe that in our reality has (so far) never been launched (apologies if that spoils the movie for anyone, but was more than 40 years ago, so I think the moratorium on spoilers has expired).
My theory is that V’Ger is a Mary Sue character, in a story written by the Voyager probe itself.
Think about it: the probe is just a bespoke wide-spectrum camera and transmitter, coasting at 0.005% of the speed of light, barely making it outside its home solar system. But somehow it was found by a race of benevolent sentient machines, and they decided it was so impressive and worthy that they upgraded it to a planet-sized vessel armed with plasma weapons.
The probe then becomes infinitely powerful and intelligent. It excels at tasks that should be impossible for it. It upstages the protagonists in the story. It even becomes the sexiest, most beautiful character in the story, with whom other characters are compelled to fall in love.
V’Ger has no flaws, and therefore no character arc describing its internal growth from a flawed character to an improved character. It has all the hallmarks of a Mary Sue in bad fan fiction.
So it’s unlikely that any of the Voyager probes from our Earth will return as V’Ger, unless Voyager transmits its amateur fiction back to us.