When bacteria was found on an asteroid Ryugu grain in a laboratory in London, the media questioned whether a sample returned from space could ever stay free of contamination from Earth.
However, no contamination has been found in the JAXA curation facilities.
But let's take a look at what that takes... (brace yourselves)
My latest on Cosmos 👉
https://cosmos.isas.jaxa.jp/keeping-out-the-earth-protecting-the-asteroid-ryugu-sample-from-contamination/