Imperial College London scientists say microbes on asteroid samples from Japan's Hayabusa 2 mission have down to Earth origins.

A Ryugu asteroid sample has been found contaminated by terrestrial microbes, raising questions about planetary protection.

Last year, researchers excitedly announced that they had found two organic compounds essential for living organisms in samples retrieved from an asteroid called Ryugu. The Japanese Space Agency's Hayabusa2 spacecraft obtained the samples from the space rock in 2019.

Scientists have found microorganisms crawling over a sample retrieved from the 200 million-mile-distant asteroid Ryugu. But they almost certainly came from Earth.

The microorganisms were seen crawling over a sample which was brought from 200 million-mile-distant asteroid Ryugu