Space debris removed from beach, origin still a mystery

The barnacle-encrusted and rusty object was found on Saturday near Green Head, about 250km north of Perth, leading to theories it could have been part of a downed airliner.

Police placed a guarded cordon around the device because of fears it could pose a public health risk, as experts worked to identify it and media speculated the military would be called in.

"Contrary to speculation, there is no evidence to support the theory that the object is connected in any way to a commercial aircraft," police said on Wednesday.

"After extensive consultation with state and national agencies with expertise in maritime, aviation, defence and space industries, it is believed the object is related to a rocket system."

The Australian Space Agency has taken over the task of identifying the equipment.

"Due to the initial assessment of the object indicating it was space industry related, and could potentially be space debris, additional precautions were taken to ensure the object posed no danger to the community," a police spokesman said. 

"All necessary measures have been taken to mitigate any potential hazards and the object is now safely contained and stored while the Australian Space Agency works to confirm its origin."

The agency earlier said the cylinder could be part of a foreign space vehicle and it was working with international agencies in a bid to identify it.

It has since said it's most likely a solid rocket motor casing.

Some users of social media site Reddit speculated the device could be Indian space junk from an LVM3-M4 rocket, as news about it was shared across the world in recent days.

WA Premier Roger Cook also weighed in, saying if the object the debris could find a home in a WA museum with the wreckage of Skylab that fell back to Earth in WA in 1979.

Skylab was the US's first space station. It was orbiting unmanned for just over five years before breaking up and scattering debris across the Esperance region.