https://www.bbc.com/news/world-australia-66220494
The item is under police guard as state and federal authorities work to identify its origin.
I'm 100 percent certain that this is a spacecraft or launcher fuel tank. I've worked on reentry analyses of spacecraft fuel tanks before, and I can tell you that these very commonly survive re-entry for several reasons.
Firstly, they are by far the largest components housed inside the vehicle's outer structure. The structure usually takes the brunt of the aerodynamic and thermal forces, protecting the tank from the largest destruction.
Secondly, the tank itself has to handle the huge fuel pressures involved (easily going towards many hundreds of atmosphere pressures!). This obviously means that incredibly tough materials have to be used.
Thirdly and finally, as can be seen in the pictures, their shape is symmetric, making the shape aerodynamically very unstable. This means the fuel tank has the tendency to tumble in the airstream. The tumbling continuously causes different parts of the tank to be exposed to the heat and other parts to cool down.
Fuel tanks are the major risk during reentry to people and other stuff on the ground, perhaps together with the massive engine blocks. To minimise the chances of hitting someone or something, re-entries are nearly always aimed at the Pacific Ocean, hence them being more likely to wash ashore in Australia.
What's the fibre pattern on the dome part I wonder? Looks like some kind of carbon fibre maybe around the top in the video.
I wonder why it was buoyant. Like if it's just the sheared off end of a cylinder you'd think it would just sink?
IDK enough about anything to say "I reckon it's x", but if it's not rocket parts then my guess would be some kind of reusable buoyancy tank used for things like floating foundations into place, shipbreaking yards, that sort of stuff.
@DogMuffins @Amilo159 Maybe it also has got some insulating foam. This would make it floatable. This really looks like some tank. It looks toasty, so the question is: 1st stage or 2nd stage?
Many "space" fuel tanks have inflatable bladders inside to control the pressure and location of the fuel, especially in zero-g. Otherwise, the fuel could float away from your tank valve. It is possible that this tank has a fully or partially inflated bladder, making it much more buoyient.
If it's an empty or near-empty fuel tank, it's going to float, whether the inside is a vacuum or pressure is equalized with a gas.
Hard to say what's inside what we can see, but if nothing else the upper visible part must have been intact and enough air still in it to keep it buoyant.
I wonder why it was buoyant. Like if it’s just the sheared off end of a cylinder you’d think it would just sink?
Something doesn't have to be buoyant to wash up on shore.
I’m the photos one can clearly see a line where part of the object was out of the water, since there’s no barnacles above that line. Also, if one were to read the article linked, one would read
(Italics mine)
"Sometime yesterday, a local lady and her partner discovered it just floating on the edge of the water and dragged it out with their four-wheel drive," he said.
I don't know enough about this to argue, so sure. We are all just jumping to conclusions though. It could have been partially submerged somewhere else, gathered the barnacles, and then relocated to this beach after a storm. Who knows...
It has been identified as (what's left of) the 3rd stage of an Indian PSLV rocket:
I only regret I can't hear them talking about it. Nobody has words for "what?" like the Australians.
WA Police said it was guarding the object until its origin could be established
Some lucky dude is getting paid to hang out next to this thing on a remote beach.
Residents visited the site on Saturday night to see the cylinder, the ABC reported, with one local describing it as a "great social evening". "It was a lovely, still night, the kids were digging sand castles around it," he told the ABC.
I sure hope there's no hypergolics left in that tank.
The tank was identified as the remains of an ISRO PSLV rocket's 3rd stage. It's the kevlar casing for HTPB solid propellant, which looks like pretty safe stuff.
Absolutely out of the question, that is definitely not a part of a commercial airliner. Built way to heavily.