Hacker News Reader

Comment by Qem | Hacker News Reader

Does simulated martian soil include all the perchlorates?

Don't think so.

https://www.npr.org/2023/11/22/1213643383/can-we-grow-veggie...

> Now, he's running an experiment growing English peas in simulated Martian soil at the Forensic Laboratory for Investigative Entomological Sciences (FLIES).

> "[This] Martian soil is manufactured on Earth. It uses data from Martian landers, and it's kind of expensive on a per-kilogram unit basis," Mendoza said, which limited the types of plants he could grow.

https://greenhouse.bios.uic.edu/news-stories/new-york-times-...

> “When they came to me and said, ‘Hey, we want to get Martian soil,’ I was like, ‘Where did you get Martian soil?’” he said. “They’re like, ‘Oh, no, we’ve got a supplier.’” It was the Martian Garden, a company based in Texas.

https://www.themartiangarden.com/tech-specs doesn't make any mention of perchlorate that I can see, even in the MDS sheets.

There are possibilities for removing and/or using the perchlorates as solid rocket propellant:

"Students Alex Hoganson, Hetal Rathore, and Chase Wernex used data from NASA's 2008 Phoenix Mars Lander to determine that Martian soil contains a 60/40 mix of calcium perchlorate and magnesium perchlorate. They worked under professor Steve Son at Zucrow Labs to synthesize and test a solid rocket propellant using that 60/40 mix as an oxidizer." [1][2]

[1] https://www.youtube.com/watch?v=zwD0a_VdS_4

[2] https://engineering.purdue.edu/ME/News/2022/can-we-turn-mart...

Yeah, it's a built-in easy source of oxygen for a base, too. Not all bad, but something to deal with.

There's a general principle for in-situ resource utilization that you want to eat the whole pig from the nose to the fingernails and twisty little tail.

As long as the extra equipment to do so isn’t prohibitive, at least.

Also depends what it is. In many situations (la Luna) volatiles are precious. I'm not so sure you want to harvest water from the Moon's north pole and use it to make fuel that will be consumed as opposed to maintaining an inventory for use in a circular economy.

I'm not sure what attitude about volatiles Martians would have. It might be able to support an atmosphere if the planet could be protected from solar radiation.

I don't see anywhere mentioning that it doesn't. I think it's obvious to make the experiment realistic one should aim for a close enough analogue of the Martian soil, and that would include perchlorates.

Commercially available martian soil simulants don’t contain perchlorates. Trying to obtain perchlorates is problematic, both from the health and law enforcement point of view.

> Commercially available martian soil simulants don’t contain perchlorates.

How do you know?

Read the MDS sheets at https://www.themartiangarden.com/tech-specs

you can remove perchlorates with dissimilatory perchlorate reducing bacteria, by rinsing the soil, by thermal decomposition in the soil, etc. there are many paths to perchlorate free soil since it is very reactive and water soluble

that was my first question too. but maybe the perchlorates can be easily broken down into oxygen and chlorides? plants can tolerate a lot of chlorides

It seems they already found a catalyst that could facilate reduction of perchlorates to chlorides with hydrogen in room temperature:

"This catalyst is much more active than any other chemical catalyst reported to date and reduces more than 99.99% of the perchlorate into chloride regardless of the initial perchlorate concentration"

https://www.sciencedaily.com/releases/2021/06/210604122505.h...

Perchlorates are highly soluble, aren't they? So, leech them out.

I anticipate growing things on Mars will be more like hydroponics than conventional agriculture. You're investing in a pressure vessel to contain the crops, so the cost per unit area is already quite high.

Aeroponics is probably a more realistic solution given the levels of water. As long as you could finely control the ratio of dissolved solids there's not much of a benefit for hydroponics perhaps beyond thermal insulation over aeroponics I think. I am not an expert though. Perhaps there's something I haven't considered though like external pressure for the plant's root vascular system provided by a hydroponics reservoir over aeroponics.

They try to create a biological catalyst and remove perchlorates from soil using Bacillus Stearothermophilus. Genetically engineered bacterium in order to create chemical pathways and break a molecule which otherwise needs huge infrastructure and big machines and manpower to operate.

Biocatalysts like that also have the potential for desalination.

I thought the microorganism was called Basiliscus and uploaded a song to YT called Space Basiliscus. Now i see it has a different name. /facepalm

Reply on news.ycombinator.com