SYDNEY — Scientists at the Australian Space Agency and the CSIRO began analysing several metal spheres found on beaches in Western Australia and South Australia on Sunday, most likely debris from re-entered spacecraft. The agency urged beachgoers not to touch the objects.

The spheres, ranging from roughly 20 to 40 centimetres in diameter, began appearing along the coast in recent days. A spokesperson for the Australian Space Agency said the objects were consistent with pressurised tanks or fuel vessels used in rocket upper stages, which often survive atmospheric re-entry intact.

Similar objects were recovered near Green Head, Western Australia, in previous years and later linked to Indian rocket launches by analysts at the agency. The CSIRO said metallurgical testing would help determine the origin and launch provider responsible for the latest debris.

The recurrence highlights the growing problem of uncontrolled space debris re-entry as launch cadence rises worldwide. The European Space Agency has estimated that a piece of tracked debris re-enters the atmosphere roughly once per day, though most burns up or lands in the ocean.

"We advise members of the public not to attempt to move or handle these objects," the Australian Space Agency spokesperson said. "They may contain residual hazardous materials, and reporting their location helps us trace the responsible operator."