Aren't submarine drones
called torpedoes?
The US Navy has successfully launched and returned an underwater drone during an undersea mission in the Mediterranean. Virginia-class attack submarine the USS North Dakota (SSN-784), was deployed to the Mediterranean for two months. She returned to base on Monday after a successful test of her drone-launching capability, …
I don't know either, but of the three options come to mind (optical, acoustic, wire) only by wire seems very stealthy and/or immune to interference. And I'd guess that optical would have the worst range limitations,and acoustic would be very good at giving away your (and its) location.
Wait, I forgot one: trained carrier piscines? :-)
Autonomous Underwater Vehicle.
Upload a mission profile and let it run. There's no operator such as you would get with the Reaper aerial drones.
Autonomous Aerial Vehicles do also exist, but only unarmed platforms running surveillance/intelligence/target drone duties, etc since any sort of weapon-release calls for human authorisation.
They're also used in civvie street for aerial surveys, scientific remote sensing, etc - send it off on a survey path and it comes back a few hours later with all your data. No need to sit at a terminal driving it all that time. Obviously locations where you can do this are limited. Oceanography is one such application - not much air traffic at 1000ft in the middle of the Atlantic.
Isn't it rich? Are we a pair?
Me here at last on the ground, you in mid-air
Where are the Drones?
Isn't it bliss? Don't you approve?
One who keeps tearing around, one who can't move
Where are the drones? There ought to be drones
Just when I'd stopped opening doors
Finally knowing the one that I wanted was yours
Making my entrance again with my usual flair
Sure of my lines, no one is there
Don't you love farce? My fault, I fear
I thought that you'd want what I want, sorry, my dear
But where are the drones, send in the drones
Don't bother, they're here
Isn't it rich? Isn't it queer?
Losing my timing this late in my career
But where are the drones? There ought to be drones
Well, maybe they're here.
And here we are learning that submarines now have new drone capabilities. This is on par with the hydrodynamic thrusters of Search for Red October. In the 1980s, this would be classified Ultra Top Secret and any journalist even trying to publish the information would be black-bagged and never seen again.
Ah, the irony of having to justify a budget.