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Comment by coldtea | Hacker News Reader

>“Since the Hayabusa2 spacecraft collected two samples directly from asteroid Ryugu and delivered them to Earth in sealed capsules, contamination can be ruled out.”

I seriously doubt that it could be "ruled out" just like that.

For one, the spacecraft (or the empty capsules) could have been pre-contaminated before their launch.

Second, the capsules could have been contaminated after arrival even if they were "sealed" (perhaps the seal had issues, or maybe it happened when they opened them, since one assumes they couldn't test still sealed capsules, they'd have to open them).

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It would be a little weird for it to be contaminated with only uracil. Sure, if they found full RNA strands you'd start to think contamination was more likely, but what are the odds it was contaminated but with only uracil, especially considering how far they've gone to prevent contamination?

I wonder if there's a "control group": a tiny but identical container that goes through all the same steps. Nothing can ever be proof that it wasn't contaminated or a seal was broken on the real but not the control container, like, nothing will convince an Internet conspiracy theorist, but a control vessel and a handful such missions ought to prove beyond reasonable doubt that it wasn't contaminated from earth. I'm personally already willing to trust that they thought of (and controlled for) these things and more, since it's their job and we're just thinking out loud here.

I don't know how they do it but I always thought the best way would be to have the probe place them in glass ampules and seal them while still in space.

> For one, the spacecraft (or the empty capsules) could have been pre-contaminated before their launch.

I had a really interesting discussion with someone who oversaw decontamination protocols and preparations for various satellites, including the JWST. The protocols they use to prep satellites for these types of missions are beyond stringent, and the chemicals they use are exotic as all hell.

All this to say, contamination is absolutely possible, but there is so much insane behind the scenes work to control for it that it shouldn’t be thought of as something they might “just forget” or casually missed.

Remember the faster than light neutrinos that turned out to be a loose cable? I doubt they "just forgot", but being perfect is more difficult than making a mistake somewhere in the process. Before they publish I would hope they Quadruple checked for every source of possible contamination. Instead of saying we did it right so obviously nothing went wrong.

I think you're reading too much into the phrase "can be ruled out." I suspect that the leader author was saying "Contamination is possible, but based on our procedures, test methods, etc, the overwhelmingly larger probability is that we did detect <...> in the samples, and that the detection was not from pre- or post-contamination."

Could the paper's conclusions be incorrect? Yes, I think everyone--the authors included--will agree that "something could have gone wrong." But pointing out that "something could have gone wrong" is probably not a new idea to most readers.

I've talked to a few scientists in this area and I found out the Viking project life detection experiments generated a lot of controversey. https://www.nytimes.com/2021/08/04/science/space/gilbert-v-l...

While we are probably really good programmers, surprisingly enough these “scientists” seem to know how to do their job without our guidance:

https://earth-planets-space.springeropen.com/articles/10.118...

Well played. I do find HN to be full of "expert" commentators on any subject matter even if they aren't ;) Remember David Levinson (Jeff Goldblum in Independence Day) figured out how to defeat the alien invaders by uploading a virus to the alien ship. He used MacOS 8! Wasn't it a modem parity issue (8N1) or some other such nonsense for a space-traveling, gravity-defying spaceship?

They can also always be too confident in having done their job perfectly - and they can be that with or without our guidance.

It’s pretty clear if you read the paper they are not confident they did their job perfectly, and have erected guard rails around everything to cap the maximal contamination and established tests for assessing the extent of contamination exploiting assuming there is going to be contamination.

I'd ask why techbro culture makes people like you so confident in areas outside your expertise, but I just answered my own question.

Google [or search engine of your choice] is your friend.

https://earth-planets-space.springeropen.com/articles/10.118...

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