There are two episodes where the glowy bits are called "Bussard collectors": "Night Terrors" and "Samaritan Snare".
There are two episodes where the glowy bits are used for venting
out hydrogen: "Night Terrors" and "Samaritan Snare".
There is one movie where the glowy bits are used for both scooping in and venting out fluids: ST:Insurrection.
Terminology varies. In "Samaritan Snare", Data mentions "hydrogen collectors" in one scene, not necessarily related to the "Bussard collectors" mentioned in a later scene. In ST:INS, the device in singular is called "the ramscoop", and its functions involve "collecting" and then "blowing out" - and the latter is achieved by "releasing" the ramscoop, although we don't see any macroscopic device being jettisoned from the ship.
And that's pretty much it. Plenty of room for speculation, then.
The bussard collectors came from Robert Bussard’s Bussard ramjet space propulsion system (this is rgal world).
But in the Star Trek world, the association with a guy or gal named Bussard might be completely different. False etymology is the eternal bane of all language...
In star trek, these devises collect hydrogen, especially deuterium, for fuel replenishment where it is collected and stored in holding tanks.
This has not been shown, stated or otherwise suggested on screen. In all the on-screen events, the use of these devices has been an exceptional measure, a rare combat maneuver, and the collection of hydrogen mr deuterium specifically has never been shown. None of the events have dealt with refueling, while none of the episodes where refueling was mentioned have dealt with Bussard collectors or hydrogen collectors or ramscoops.
To work, they would need to be in a good forward line of sight to collect interstellar particles.
Alternately, they'd need to be off the FLOS because the FLOS is already devoid of interstellar particles. After all, the navigational deflector is tasked with keeping it empty.
However, the warp coils require warp plasma, not straight deuterium to work; also, the deuterium tanks are in the secondary hull.
Again noncanon hearsay, if we're allowed to nitpick...
Also, why bother to collect matter if you aren’t going to collect anti-matter also? Without equal stores of both, you’re just hauling empty weight around.
Rockets work on empty weight (aka propellant); perhaps starships have rockets that need propellant (that only has to have mass), in addition to having things that need fuel (that also has to feature extractable energy, such as chemical or nuclear bonds)?
We do know that the glowy bits next to the nacelles are present in some 99.9% of Starfleet designs - although we also know warp can be achieved by quite different designs, including ones that feature nacelles but not glowy scoops. Since Starfleet are the good guys, perhaps the glowy scoops are a particularly environmentally friendly thing (that is, indeed a way to get extra fuel without relying on the Trek equivalent of nasty and dirty oil drilling platforms)? Warrior races wouldn't often bother with them, then. Or perhaps they alter the ship's emission signature ("scoop out noise factors") so that it's easier to do scientific measurements? Another thing only Starfleet would usually bother with.
Personally, I think the scoops are there simply to serve as snow plows: they remove obstacles, and warp engines work best when obstacles are removed. More barbaric cultures simply ram through galactic soot, but the Feds neatly sweep
and suck it away, using both deflectors and ramscoops. Whether they get anything extra out of it, such as fuel replenishment, is debatable.
Timo Saloniemi
