Babylon 5: "Voices of Authority"
Babylon 5: "Voices of Authority." Season 3, episode 5 (29 Jan. 1996).
Covered briefly in Frank Garcia's "Babylon 5 Episode Guide," Cinefantastique 31.12/Vol. 32 No. 1 (June 2000): 73-74. See Babylon 5 entry for link to locations on line where the relevant Cinefantastique issues are likely to be archived.
In the Cinefantastique sidebar, we're told, "Sheridan accepts Draal's [...] offer to use the Great Machine in searching for 'the First Ones.' Ivanova steps into the Great Machine's chamber and in her mind she floats through the depths of space." We learn on the Babylon 5 fan wiki,
Powered by a massive network of advanced fusion reactors, some of which are up to 10 miles across, this complex machine required a sentient being to merge with it in order to regulate and stabilize its operation. With the colossal amount of raw power at its disposal, the machine is known to be able to boost a tachyon signal over dozens of light years, project the operator's mind clear into deep space and even control and widen a temporal rift. The Machine also features a holographic system that can scan and project images at least as far as near orbit and even blanket all local signals. Though extremely advanced by the standards of the Younger Races, the machine has its limits and can be blocked by a sufficiently advanced race, most especially the First Ones.
The fan wiki indicates the Machine "appears to have been at least partly inspired by" the highly impressive planet-wide machinery of the Krell in FORBIDDEN PLANET, so it's unfortunate for our purposes that the Cinefantastique interview with Larry TiTillio indicates "We never saw that Great Machine [...] again!" (p. 74). No exactly on never again; The Great Machine is also in "Babylon 5: "War Without End" (Pt. 1)," which see.
RDE, finishing, 18Aug22, 31Aug22