Not sure if it’s stated in canon when they started doing this
2150s. No, seriously. That’s been a thing since Archer. Hull polarization actually started as the first line of defense before shields became common place and much stronger. The NX Class and the Shuttlepod both had polarized hulls. They even make a mention in one of the episodes that while they’ve been away from Earth for months that Earths polarization tech has improved efficiency by 12%. But when shields started gaining more ground and traction, hull polarization wasn’t needed as much so it slowly slid to the background and was only used when necessary like when Voyager needed more stability or when the Delta Flyer was trying to be located. I remember something else about using it to modulate against a tractor beam too somewhere in DS9.
That being said, I’m not sure where you’re getting the information about constant polarization and deflecting space dust. Typically that’s what the deflector array was for. I’m not saying you’re wrong or anything, it’s Star Trek. There’s tons of inconsistencies and backups and redundancies. I’m just curious so I can add it to my giant folder of useless Star Trek info that’s buried in the back of my brain.
Edit: There is zero source material to back up the claim that the hull polarization reflects space dust and this guy seems to be acting on bad faith. I’m just going to go ahead and take everything he said here with a grain of salt the size of a D’Deridex.
I’m aware of when hull polarization began being used, but one can infer from more recent dialog that it’s now a “constantly-on” feature.
Also, the deflectors are typically for use at warp speed as they project forward from the deflector dish. A polarized hull is useful at sub-light.
The deflectors are vital at warp speed but they’re still on at sublight speed. I also cannot find a single mention of polarized hull ever being used to repel dust/dirt at any speed. That’s why I asked. Memory Alpha doesn’t address it at all and google is returning zero results. I also cannot think of any recent dialog ever mentioning something to that effect. The closest I can think of is the Cerritos but their hull wasn’t polarized, it was had magnetic shielding.
