Expanding space travel sector could bring 'alien organisms' to Earth, scientists warn

A new study has suggested alien organisms could get to Earth by hitching a ride on our own spacecraft.

The study, published last week in the journal BioScience, called for biosecurity measures to be overhauled as space travel and exploration expanded.

"Sophisticated protocols are required to prevent biological contamination of extraterrestrial environments from Earth and vice versa," the study authors wrote.

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"Such protocols should be informed by research on biological invasions - human-assisted spread of organisms into novel environments.

"Collaboration among astrobiologists, invasion biologists, and policymakers could greatly enhance planetary biosecurity protocols."

The authors compared the impact of a potential alien "invasion" to the consequences of humans introducing a foreign species to a new environment.

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Australia's own ecosystems have been broadly damaged by European introduction of animals such as cane toads, rabbits, and - arguably - livestock species.

The authors conceded that the chances of importing a dangerous alien organism to Earth were slim, but that the potential consequences could be so far-reaching that, as with other rare potential disasters such as nuclear meltdowns or major earthquakes, preparation was needed.

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"Space is emerging as a new frontier of biosecurity risk," they wrote.

"In addition to government-led space missions, the arrival of private companies (e.g., SpaceX) and new international players has caused space to be accessible by a broader range of actors than was ever possible previously."