Navy demonstrates multi-day solar UAS flight | Hacker News Reader

Navy demonstrates multi-day solar UAS flight

navair.navy.mil

90 pointsbookofjoe43 comments

The article mentions that this Skydweller UAS completed a 73 hour flight.

Back in 2022 there was a solar powered Airbus Zephyr drone that was tested over the Southwestern US with a flight time of 64 DAYS. I wonder how this new drone is different and how a 73 hour flight is significant in comparison.

Here is an article about the Zephyr Drone and its crash that ended its nearly record-tying flight:

https://simpleflying.com/airbus-zephyr-flight-ends/

Here is a flight replay from adsbexchange showing one day's worth of its flight path where it traced out the Liberty Bell(?) and the shape of the lower 48 at nearly 70,000ft. (Scrolling through its other dates show more playful flight paths)

https://globe.adsbexchange.com/?icao=ae1313&lat=33.419&lon=-...

It looks like that Zephyr drone only weighed about 160lbs and didn't carry any payload. I believe these new Skydweller drones can carry an 800lb payload. Maybe that is the significant difference?

Thanks for the clarification. That is significant

The Skydweller is capable of carrying an ISR (Intelligence/Surveillance/Reconnaissance) equipment load, which is several times heavier than the Zephyr -- not to take away from the Zephyr's accomplishments ("on the shoulders of giants", etc).

The article mentions "wide-area surveillance"[1], which translates to "a lot of cameras" (FLIR, visible light, etc).

You also need more solar and more batteries to power all that ISR.

1. https://en.wikipedia.org/wiki/Wide-area_motion_imagery (eg. GORGON STARE)

>You also need more solar and more batteries to power all that ISR.

I wonder if it would be feasible to use smaller sensors and on a smaller platform - then combine that data. Similar in concept to Gorgon stare where the idea was to combine data from multiple UAVs to create a larger image to provide a greater simultaneous coverage area.

https://longreads.com/2019/06/21/nothing-kept-me-up-at-night...

Mesh is the fad in the military right now, so I imagine this was designed with that in mind. On the other hand, the military likes its sensor data, so it's always going to go big.

I worked on non-maritime stuff, so I'm not familiar with maritime-specific sensors.

The smaller you make the sensors, often the closer you have to get to the thing being observed.

Cameras, optics, RF circuits, etc.

This was envisioned by the movie Interstellar where the opening scene shows them chasing an old autonomous Indian Air Force drone that had been flying for years, ostensibly after that agency ceased to exist. I'm sure it's been in other media as well but that's what comes to mind here.

Anyway, it should be interesting to see where this goes in the future.

Probably gets shut down due to being woke green technology.

And then we'll restart the research into nuclear powered aircraft instead!

This was the central theme of https://www.youtube.com/watch?v=IjJmTeBSEzU

I am still skeptical it would work out for regular aircraft due to all the moving mechanical parts, not o mention battery charge cycles for night flying.

But I could definitely see it working for autonomous underwater drones that glide in the water, going up and down by changing their density. Few simple mechanical parts & some project already demonstrated very long endurance.

regarding battery cycles, what if they used something like a bank of capacitors that would be much lighter?

I think capacitors would be heavier, they have less energy density than batteries. They have high power density and they last more cycles, but for a given number of watt-hours they'd be bigger and heavier

how about a autonomous plane that mostly rides the air currents?

I’m probably hugely oversimplifying here but let’s say you attach the electric motor directly to the prop, perhaps with some minor gearing, then what’s left in terms of moving parts? Some rudders, right?

Usually prop is directly attached to electric motor. If it's a flying wing then mechanical part is literally motor plus to ailerons. With little efforts thing cam be made hard to destroy even intentionally with heavy machine gun.

Mechanical failure is usually a probability distribution and with a large enough population, you get outliers.

https://en.m.wikipedia.org/wiki/Centennial_Light

“ The Centennial Light is an incandescent light bulb recognized as the oldest known operating light bulb. It was first illuminated in 1901, and has only been turned off a few brief times since.”

Off topic, but if I slide left to right I get a tutorial jquery.mmenu on this page.

For everyone who can't access thes site because of country restrictions: https://archive.is/jtKfH

Very cool. I've been wondering on the upper limit on this for a while: Indefinite autonomous flight. Upper atmosphere or lower. I think I was inspired by SevenEves' gliders, but in my head, they would be small (er than depicted in the novel, and this article)

I think altitude is what would make these valuable. If you can approach LEO and away from standard military tech, they could easily prove refreshable tech platforms.

Did it follow the sun around the world or did it circle around its launch location for three days?

Not sure about this one but previous multi day attempt were not tracking the sun. They go really high during day and then use battery and altitude to make it through night

To follow the sun it would have had to fly over 1000mph for the whole duration of the flight. So I guess it circled

Looks like the US is working on their own Arsenal Bird.

I wonder what sort of payload it has. Could this conceivably lift a person?

Supposedly it can carry up to 800 pounds (https://www.skydweller.aero/), although not clear what was tested.

At first sight I read 'nuclear' instead of 'not clear' and I got scared. Then I though about it again and... sadly it could also be true.

Why? ICBMs can be launched and strike their targets within 15 minutes.

You underestimate the value and strategic purpose of second strike. https://en.wikipedia.org/wiki/Second_strike

By definition fired after you've already been hit with nuclear weapons.

Second strike is the deterrent measure to nuclear war, so why would improved second strike capability be a source of fear?

Even when slow, a relatively small, high altitude, no refueling, low heat signature plane with a small tactical weapon could be interesting for... reasons.

It seems like it could, but that's not this model's mission: https://www.skydweller.aero/perpetual-flight/

Yes. It is indeed based on the Solar Impulse 2, the first manned solar aircraft to circumnavigate the earth.

https://alert5.com/2025/07/30/converted-solar-impulse-2-airc...

You can use 'circumvent' here, but the meaning is a little odd. That's more like heading from Mars to the Sun and finding a way around the Earth to continue to your destination. Usually, people use 'circumnavigate' instead, which is used to describe vehicles (boats, planes, bicycles, etc.) making their way all the way around Earth.

One possible payload would be a fast deploy cellular base station that can loiter over disaster areas to provide connectivity. Backhaul would be via satellite like Starlink or if you have multiple aircraft you can route between them to a place with working connectivity. They could also broadcast FM emergency update info.

Presumably they could also be rented for big commercial outdoor events, too. On a grander scale, maybe these might make a big network like the old Project Loon more feasible, though presumably the things would have to be able to fly high enough to escape most of the weather (and vandals and conspiracy theorists armed with rifles).

If you ever dig through Tarana's patents, what you'll come across is more or less what you're describing.

I had to look up UAS (Unmanned Aerial System) as the only related acronym I knew previously was UAV. I bet I'm not the only one here who had to do that, rather I'm the only one (so far) to confess his ignorance.

Looks like UAS became a more popular search term than UAV as of June 1st, 2015.

https://trends.google.com/trends/explore?date=all&geo=US&q=U...

That plane is extremely hollow; you can clearly see the deformation because its not extremely rigid. It's some sort of thin high strength fabric over a minimal skeleton.

I'm not sure what you are basing that assessment on. Hollowness is a given for an aircraft of it's size, but I can't say I see any signs of it being extremely so. At least from the pictures of the article it is definitely not clear that it would be deforming unusually much.

Quickly checking the construction is carbon fiber, which is kinda no-brainer.

Reply on news.ycombinator.com