How do Droidekas fire blasters through their shields?

Question

In the Star Wars universe, it's usually the case that shields can block energy weapons (blasters, lightsabers, lasers) but don't do much against physical objects (rocks, bullets, spacecraft). This is how they work in the new Battlefront game, where they protect against everything except explosives and slugthrowers.

In-game, the card for the personal shield powerup describes it as adapted droideka technology, and, notably, you can't fire your weapons while inside a personal shield. This may be for game balancing purposes, but it does raise the question: how can droidekas shoot through their own shields when no one else's energy weapons can? Are there any other examples of one-way shields in Star Wars? It's unlikely there's going to be much new canon material about this, so Legends answers are fine.

Answer 1

On careful examination, the Droideka's gun turrets appear to extend outside of the defensive shield. When they fire, they either do so with the muzzle precisely aligned with the front of the shield or simply with the gun sticking right outside. The recoil obviously brings the blaster arm back inside the shield, presumably this also prevents their opponents from deflecting the shot back into the gun's muzzle.

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Interestingly this is somewhat contradicted by the (canon) Studio Fun - Star Wars: Droid Factory factbook which strongly implies that the shields are somehow modulated to block enemy fire, but to allow the Droideka's own bolts to pass through.

Answer 2

Firing through one's own shields isn't a new thing.

• In The Empire Strikes Back, the Echo Base shield generator (on Hoth) is protecting the base from bombardment, however, the base is still able to fire its ion cannons at the Star Destroyers while the Rebel Alliance fleet flees. They only had to turn it off in order to let the ships out.

• In Return of the Jedi, the shield generator is still operating when the Death Star opens fire on the Rebel Alliance fleet.

• Throughout the series you hear people talking about angling or activating the shields (such as X-Wing pilots, Han Solo, or Star Destroyer Bridge Officers) all while engaging in blaster fire combat.

Shields are still two-way, if something is moving slow enough.

Droideka shields were ineffective against slow rolling objects, such as thermal detonators which could be rolled in and detonated. - http://starwars.wikia.com/wiki/Droideka/Legends

Answer 3

In real world, WWI pilots shot trough their own propeller without any problem at all.

So, apart from the above answers pointing to the weapon standing outside of the shields (which all are correct on their own), there is nothing suggesting a droideka can't do the simplest thing of all: powering off the shield for an instant, shoot, rearm the shield, and so on. I'm not in any way saying that this is a canon answer or what, just pointing out that there is no need for a one-way shield justification.

Answer 4

In Season 5 Episode 4 of The Clone Wars, which is canon and not part of the EU or Legends, a character jumps through a shield, but when he tries to fire a grappling hook out, it rebounds, demonstrating a one way shield. This is a clear example that the Separatists have one way shields.

However, this is not solid evidence as the shield demonstrated is made of hexagonal panels and is invisible, but when activated turns red. also, both examples block slow moving solids, such as grenades. This is the best canon explanation I can think of, hope it helps.

Answer 5

The X-Wings had one way shields, as during the Battle of Yavin, you see and hear the pilots activate deflector shields as they are firing their cannons.

Also, keep in mind that the droideka shields are a bit weaker than starship shields. You see them deflect hand held blasters, but when they take a shot from a fighter, they are blasted to bits.

Think of it this way: droideka shields are tuned to a specific frequency and deflect anything that isn’t matching (kind of like how polarized lenses work), and the frequency of their guns match the shield frequency so they can pass through. Star Trek covered this before in Generations; the Klingons managed to get a the information of the Enterprise’s shields and tuned the phasers in such a way that the shields couldn’t deflect them.

Answer 6

I don't have direct canon answer, but these are the possibilities I can think of:

• In the Star Wars: The Clone Wars TV series, it was explicitly said that those shields can be penetrated with slow motion things. For example, you can drop a grenade under their shield if you push it slowly. And that's why lightsabers are able to penetrate the shield, too. This feature of shield allows them to move in a non-tidy battlefield environment. Probably, the feature also allows them to shoot. Guns are little bit behind the shield and it push blaster bolts such that it picks up speed above threshold after crossing the shield.

• Guns really extend to outside shield. This doesn't need to be too much. It just needs to touch the outer layer of the shield.

• From Star Wars: The Force Awakens, we know that shields

  have Refresh Rate. This refresh rate can be adjusted

to accommodate blaster bolt passage.

• This is slightly out of canon (took from Star Trek), but worths mentioning: Blaster Bolts and shields are in phase. I don't know exact nature of Blaster Bolts, but if it's made of free quantum denizens, it means it'd show wave properties. As phase settings (which can change every second) of shields are only known by the droid, an outside Blaster Bolt can't penetrate it.

Answer 7

Shields have on occasion flickered off in Legends material to allow for firing weapons, but this is typically one of two cases - a planetary shield, or a particularly unusual/unique shield or weapon. This is probably not how Droidekas work, because the inconsistency here is introduced by Battlefront, in a noncanon thing that is just a gameplay device rather than an in-universe fact - chalk it up to the individual shield technology they're using.

As supporting evidence, I would point out that the Death Star exhaust port was specifically only shielded against blasters, but that the line describing it as such strongly implies that this is unusual, and that many other things are ordinarily also shielded against physical objects such as proton torpedoes - and this is also the position taken by Legends continuity on shields in general, described as "ray" and "particle" shielding - so Battlefront shields are already unconventional, if it's impossible to build them to stop particles!

Answer 8

Totally outside canon, using some general physics, and some borrowed Star Trek theory comes the following ideas:

The droids "consciously" create the shields (because they detect a threat). They should be capable of controlling the "harmonics" of such shield. Droids, being very fast compared to a flesh-and-blood being facing them, should be able to adapt the shield harmonics seamlessly so that blaster shots out are minimally obstructed or unobstructed with such a timing that even a saber-deflected return shot would hit a full-force shield.
The droid is firing through a weak or non-existant part of the shield that is immediately reinforced after firing.

Alternately, if the harmonics thing is too treky, consider that the droids could "drop the shields" just long enough to fire the shots, and then put the shields back up. All of this would be sufficiently fast that a human (or other humanoid) would never even see a visible change in the shield's visible output (still significantly faster than what film could possibly capture).
Like when Enterprise drops shields just long enough to transport someone up and then immediately reengages the shield.

Finally (or TLDR): A wizard did it.

Yes, all this disregards the game related reasons (excuses?) for why something does or doesn't work some way.