Aug 9Liked by Erika Alden DeBenedictis, Pioneer Labs
Very cool! The step-by-step approach seems like a sensible way to progress towards an organism that can survive unassisted on Mars.
About the four extreme conditions you've mentioned (salt, perchlorate, cold, radiation), are there known microbes that can survive each independently to the extent present on Mars, so that the challenge is combining all that in a single microbe? Or are some of the conditions beyond what any known life tolerates?
Salt and perchlorate - yes - there are examples of organisms that can tolerate Mars conditions. Radiation is probably also OK assuming you have a *little* shielding composed of dirt/water/dead cells above you. For these three, the challenge is combining these traits into a single organism
The main issue that makes Mars tough is cold. You almost certainly need to heat Mars up, perhaps about 30C, before organisms could actually *grow* at a reasonable rate. Warming things up can be done in a greenhouse for agriculture, and there are even some proposals for how to heat Mars at scale https://www.science.org/content/article/terraforming-mars-could-be-easier-scientists-thought
That would probably work over the long term! But it takes thousands of years for new mechanisms to evolve naturally. It's much faster to source already existing extreme tolerance.
Very cool! The step-by-step approach seems like a sensible way to progress towards an organism that can survive unassisted on Mars.
About the four extreme conditions you've mentioned (salt, perchlorate, cold, radiation), are there known microbes that can survive each independently to the extent present on Mars, so that the challenge is combining all that in a single microbe? Or are some of the conditions beyond what any known life tolerates?
It depends on the extreme.
Salt and perchlorate - yes - there are examples of organisms that can tolerate Mars conditions. Radiation is probably also OK assuming you have a *little* shielding composed of dirt/water/dead cells above you. For these three, the challenge is combining these traits into a single organism
A couple example organisms:
- Debaryomyces hansenii can grow in 23% perchlorate solutions https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7281446/
- D. radiodurans & other species can survive that for on the order of minutes totally unshielded, and vastly longer slightly shielded https://www.sciencedirect.com/science/article/abs/pii/S0019103505004021
The main issue that makes Mars tough is cold. You almost certainly need to heat Mars up, perhaps about 30C, before organisms could actually *grow* at a reasonable rate. Warming things up can be done in a greenhouse for agriculture, and there are even some proposals for how to heat Mars at scale https://www.science.org/content/article/terraforming-mars-could-be-easier-scientists-thought
Interesting, so that's another point in favor of tolerating the regolith as a first step.
Fascinating! Can't wait to read more in the future
What about growing some microbes in a container and piping in a tiny bit of Mars atmosphere/soil over time... this way it could naturally evolve.
That would probably work over the long term! But it takes thousands of years for new mechanisms to evolve naturally. It's much faster to source already existing extreme tolerance.