[HN Gopher] Manta Ray UUV prototype completes in-water testing
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Manta Ray UUV prototype completes in-water testing
Author : Luc
Score : 68 points
Date : 2024-05-03 15:22 UTC (7 hours ago)
(HTM) web link (www.darpa.mil)
(TXT) w3m dump (www.darpa.mil)
| heyflyguy wrote:
| There was a giant NOTAM in the pacific a few weeks ago. The title
| of the TFR was "MUTANT MEGALODON". A1396
|
| I am curious if these two things were related.
| dylan604 wrote:
| I am and am not at the same time surprised that humor is
| allowed in this mode of communications.
| IncreasePosts wrote:
| Why would airmen need to know about a submersible?
| timdiggerm wrote:
| because they don't want anyone observing the testing
| quercusa wrote:
| Somebody on X caught it:
| https://twitter.com/SeanMoodyNews/status/1776676474407297224
| Scene_Cast2 wrote:
| I wonder why it needs wings underwater.
| hamandchris wrote:
| Something about this? "Once deployed, the vehicle uses
| efficient, buoyancy-driven gliding to move through the
| water..."
|
| Sounds like it gets around by changing buoyancy, which is
| pretty cool and also probably completely silent.
| causal wrote:
| It's still much wider-bodied than any glider I've seen. I'm
| guessing this is because of the need for larger payload bays.
| ryanisnan wrote:
| The answer is probably explosives, but are there other
| payloads you think this thing might carry?
|
| Comms? SIG-INT equipment?
| causal wrote:
| Given the autonomous nature I'd be surprised if it were
| used offensively anytime soon, so I'd guess the latter.
| marcosdumay wrote:
| You don't need as much wing-area underwater as you need on
| the air.
| zardo wrote:
| The real benefit is it works well with harvesting energy for
| propulsion from the depth based thermal gradient.
| EA-3167 wrote:
| The same reason that rays and skates have wings, they're useful
| in any fluid medium, even when they aren't generating lift.
| krisoft wrote:
| > even when they aren't generating lift.
|
| Yes. But these do generate lift. This is basically an
| underwater glider[1]. It can change it's buoyancy which would
| make it sink/raise straight down/up. It uses then its wings
| to turn this vertical speed into horizontal propulsion. It
| basically flies underwater in a sawtooth pattern (when seen
| in a side view).
|
| This is a very energy efficient way to go the distance. These
| machines can loiter for months on a single charge typically.
| They only need to spend energy on the top and bottom points
| of their vertical swoops to change their buoyancy.
|
| 1: https://en.wikipedia.org/wiki/Underwater_glider
| ceejayoz wrote:
| Same reason fish, marine mammals, submarines etc. need fins.
| sigzero wrote:
| To look like a manta ray?
| erikig wrote:
| I was wondering how this UUV was powered and all that DARPA was
| willing to divulge was "Novel energy management techniques" and
| "undersea energy harvesting" [1].
|
| Anyone have any insights?
|
| [1] https://www.darpa.mil/news-events/2024-05-01
| causal wrote:
| I saw an Instagram Reel where someone claimed it could loiter
| on the seabed for extended periods powered by geothermal, but
| that sounds pretty fanciful to me.
| runjake wrote:
| This is an inaccurate take. It loiters on the bottom in an
| energy-efficient sleep mode.
|
| Separately, it collects small amounts of energy via
| geothermal means similar to something like regenerative
| braking. This, of course, allows it to sleep for longer
| periods.
| causal wrote:
| That definitely makes more sense but where did you learn
| this?
| runjake wrote:
| From both a defense publication article, written by the
| Program Manager, Kyle Woerner, and reading up on the
| company purportedly behind the geothermal research. They
| go into a bit more detail.
|
| If I can find online links, I'll post a follow up comment
| with them.
| zardo wrote:
| https://www.whoi.edu/oceanus/feature/green-energy-powers-und...
| 2rsf wrote:
| The article mentions Seatrec that have more information:
| https://seatrec.com/technology/
| conradev wrote:
| It's an underwater heat pump!
| great_psy wrote:
| Does not 'seem' like the right shape for it, but could it use
| ocean currents ?
|
| Similar idea to those weather balloons we were talking about
| last year ?
|
| Is that even possible in the ocean ?
| JKCalhoun wrote:
| There are definitely underwater gliders:
| https://en.wikipedia.org/wiki/Underwater_glider
| jauntywundrkind wrote:
| It's afaik the only glider type UUV (ed: being looked at by
| .mil. and production intended. and bigger than the research
| gliders by far.), afaik. Which is super interesting in itself,
| for endurance purposes. But perhaps this depth-changing mission
| profile is also key to its energy harvesting?
|
| Just guessing here, but... it's sinking and rising. Well,
| perhaps it can take some mass of water onboard & run
| temperature differential energy harvesting off that. Take on
| warm surface water, slowly glide down 1000 ft (while going much
| further forward), then run a thermo-electric generator against
| the cold deep. Swap water & take 300 gallons of cold water,
| glide up 1000 ft (and forward), then run a thermoelectric
| generator against the warmer surface water or the air and/or
| solar. Repeat ad-infinitum. No idea what kind of power you
| could pull here but maybe, and it fits with the glider core
| concept.
|
| And yeah, maybe if you do find an underwater vent you can
| supercharge? :)
|
| Shout out to The War Zone (TWZ)'s coverage over time. The
| recent is decent but links their previous which looked about
| some. https://www.twz.com/news-features/manta-ray-underwater-
| drone...
|
| TWZ talk about something mentioned elsewhere in the comments,
| yes, the data-linking challenges are partly tackled by having a
| _" data bubble_" that can float to the surface & uplink, who
| knows, maybe downlink relay too (unspecified). I definitely
| want to imagine the data bubble as a recursive system, as
| itself a smaller glider drone, but I'm 100% making that up, is
| my sci-fi impulse.
| JKCalhoun wrote:
| Is this not a glider?
| https://en.wikipedia.org/wiki/Underwater_glider
| wolverine876 wrote:
| This article covers it in more detail:
|
| https://www.defenseone.com/technology/2024/05/giant-military...
|
| _"One thing that you notice in underwater vehicle design is
| you typically can have either a vehicle that lasts very long
| periods of time but can 't really carry anything with it,"
| Woerner said on a podcast in 2022. "But if you want something
| that can carry a sensor or payload that is perhaps a larger
| size or mass, or has a larger energy draw, you tend to need a
| more traditional underwater vehicle, propeller driven in most
| cases. And those tend to not have anywhere near the endurance"
| that the military is looking for.
|
| The ocean itself is full of potential sources of energy, such
| as currents, waves, and even subtle differences in water
| temperature or salt levels. But there's no single perfect
| source of ocean energy for what DARPA is trying to accomplish.
|
| "If you're interested in maybe closer to surface transport,
| wave energy is a really great resource, most of the wave energy
| is distributed near the surface. If you want to go into deeper
| water, right? That means that wave energy wouldn't be a great
| resource for that," Sandia National Laboratory engineer Kelley
| Ruehl, an advisor on the program, said on the podcast.
| Similarly, current energy is a very localized resource, where
| we have tidal streets-- those are unique locations in the
| world. So it's a very specific place that one would need to
| harvest tidal-energy resource."
|
| DARPA said PacMar Technologies, another contractor on the Manta
| Ray program, will spend the rest of this year testing a full-
| scale energy-harvesting system._
| jfaulken wrote:
| I read that as "Manta Ray Unscrewed ..." and could not process
| the rest of the sentence.
|
| Are manta rays attacking underwater vehicles now?
| 0x457 wrote:
| Glad I'm not the only one. Tooke me awhile to figure out.
| pineaux wrote:
| Same here
| alistairSH wrote:
| Same. I had to read your comment and title several times each
| before it clicked.
| manuelkehl wrote:
| Came here to write a comment along those same lines haha
| nielsbot wrote:
| Same. I was like "oh, so we have caterpillar drive in real life
| now?" (assuming screw = propeller)
| aaroninsf wrote:
| I wonder if there is a name for garden-path sentences which
| emerge from mis-reading or typos; or, more interestingly
| perhaps, a name for a garden path candidate sentence--which is
| being optimistically projected during reading-- _forcing_ a
| misreading.
|
| An interesting sort of confirmation bias, which it is easy to
| interpret as "pressure from more abstract model layers,
| informing the word recognition layer"...
| hammock wrote:
| It's been studied.
| https://osf.io/preprints/psyarxiv/w53k8/download
|
| "Rational inference and good-enough processing actively trade
| off with each other during reading."
|
| A slightly broader term would be "illusory inferences"
| zwieback wrote:
| Same, and now I'm fantasizing about the Netflix movie about
| manta rays unscrewing submarines
| not_your_mentat wrote:
| I was thinking, "That's a rude way to describe manta rays
| having reproductive problems."
| patrickhogan1 wrote:
| This thing is giant I wonder what a whale will do to this.
| jeffbee wrote:
| It appears to be "giant" in the way that a small private
| airplane is "giant". It is larger than a sandwich but
| significantly smaller than all other underwater craft.
| josefresco wrote:
| Another article on this: https://www.twz.com/news-features/manta-
| ray-underwater-drone...
|
| Title: Manta Ray Underwater Drone Even More Enormous Than We
| Thought
| causal wrote:
| Biggest issue for AUVs is how water attenuates radio, meaning
| this will have to surface to phone home. Guessing it will mostly
| be used for surveillance.
| tiahura wrote:
| Given its size, it could hold a number of cheap small satellite
| communicators (ie garmin inreach) that could be deployed to
| slowly float to the surface and phone home as needed.
| lupusreal wrote:
| Bouyant antenna cables are old tech, no need for the entire
| craft to surface.
| lupusreal wrote:
| Heh, kinda looks like Arsenal Gear.
| pineaux wrote:
| This thing is going to be absolutely encrusted with barnacles af
| some point. How cool is that?
| mc32 wrote:
| That's going to be a drag.
| 082349872349872 wrote:
| When there's no crew to keelhaul, why even bother with the
| barnacles?
| bitlevel wrote:
| Saw the headline, immediately thought of Voyage to the Bottom of
| the Sea with Seaview and the smaller Manta craft.
|
| Fewer humans onboard though...
| erksa wrote:
| > Manta Ray vehicle being towed in preparation for testing
|
| Find it funny that they have to tow the prototype for some
| reason. Good to know DARPA also releases half-done prototypes.
|
| Lighthearted fun this morning, and not to be taken serious.
| knowaveragejoe wrote:
| Every prototype of anything large like this would be towed
| around, why would this be different?
| its_ethan wrote:
| I know it's pointless pedantry and there's no reason to argue
| it, but aren't prototypes inherently "half-done"? If something
| was "fully done" it wouldn't really be a prototype anymore, but
| more of a gen 1.
| luma wrote:
| Large ships regularly leverage tugs to get in and out of
| harbor, this isn't even a little unusual.
| erksa wrote:
| Neither is having a prototype being assisted by external
| forces when demoing. :D
|
| All in good fun and all of this is way outside of my area.
| It's been exciting to see, just thought it was funny that the
| first images are the thing being towed.
| ItCouldBeWorse wrote:
| Not really drone-lego yet, but at least partially modular..
| briandw wrote:
| Sounds like they are using a
| [Buoyancy_engine](https://en.wikipedia.org/wiki/Buoyancy_engine).
| The large wings are there to provide efficient forward motion
| when going up or down the water column.
| holoduke wrote:
| I always wonder how these aircraft deal with sea life and debris.
| The first 0 to 20 meters of sea is the most dense populated zone
| in the world. How do you deal with collisions? I think therefor
| this will never be a success.
| dylan604 wrote:
| What the huh? This has to be a joke, yeah? Those things in the
| sea move out of the way when things that appear threatening
| move through the area. Why would this be any different to that?
| Or to any other man made vessel in that same area. I only typed
| this out in case you're having a brain fart, otherwise I really
| feel like there should be cameras around like I'm being punk'd.
| zardo wrote:
| Catching floating kelp would be a real concern. I doubt the
| plan is to spend much time near the surface though.
| neeleshs wrote:
| UUV (Uncrewed Underwater Vehicle) is a meh acronym. CrewL(l)ess
| Underwater Boat would've given them CLUB or CUB!
| dgfitz wrote:
| It is just part of the same vernacular as: UAV (Unmanned Aerial
| Vehicle), USV (Unmanned Surface Vehicle), and UGV (Unmanned
| Ground Vehicle). So UUV (Unmanned Underwater Vehicle) lines up.
| Razengan wrote:
| Carrier Command (1988) can finally be a reality:
|
| https://en.wikipedia.org/wiki/Carrier_Command
| dvh wrote:
| Why it needs vertical control surface? Why manta ray don't need
| one?
| tambre wrote:
| I'm guessing, but manta rays are flexible and can form vertical
| surfaces by how their wings flop. Or maybe they just can flop
| their wings different amounts to generate differing thrust for
| turning.
|
| Neither is possible with todays technology. Adding a vertical
| control surface is a pretty easy solution though.
| braymundo wrote:
| Major X-COM: Terror from the Deep vibes.
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