Here's what we know about planetary protection on China's Tianwen-1 Mars mission - Space.com

Because scientists have high hopes of someday discovering traces of life on Mars, spacecraft that will land on the planet are kept as immaculately free of Earthly life as possible.

"I don't know anything beyond what all the rest of us know from the public releases of information, but they do participate," Lisa Pratt, NASA's planetary protection officer, told a virtual meeting of the committee leading the creation of a new decadal survey identifying the priorities of planetary scientists into the 2030s on Feb.

One tenet of the Outer Space Treaty refers to planetary protection, stating that countries must explore other worlds "so as to avoid their harmful contamination.".

For one, scientists don't want any Earth creatures to be able to make a home for themselves on Mars; for another, scientists want to be confident that if they detect traces of life on Mars, that sign is indeed from Mars, not some wayward fingerprint that came from Earth.

(When it comes to planetary protection, sites with water are always scientists' top concern.) Long ago, however, there may have been ancient groundwater deep below the surface and mudflows in Tianwen-1's landing zone.

The twin Viking landers were the first spacecraft that NASA engineers sampled before departure, archiving organic and biological material from them so that if instruments detected a potential signal of life, scientists could compare such data to the samples remaining on Earth.

Launched in the 1970s, the Viking mission still predated NASA's earnest planetary protection standards for Mars.

And China is likely in the same place, Pratt said, noting that Chinese scientists do have contacts with a key Italian planetary protection team, so should be aware of current standards. !

However, while NASA and its Chinese counterpart can't interact directly, sometimes their representatives end up at the same meetings, and Pratt told the story of just such an occasion, which she attributed to November, when she ended up seated next to a Chinese scientists.

"I asked a question in front of everybody, I said, 'Can you talk to us about what you did for planetary protection compliance?'" Pratt told the committee!