Announcing the First Microbe for Mars

A useful, safe, first step toward terraforming

If you want to terraform Mars, where do you start? When Pioneer Labs began two years ago, we looked for a way to break down this ambitious goal into actionable stepping stones.

We knew that the first step we took had to be three things:

• 🌼 On the path to terraforming - de-risk a key unknown.

• 🪵 Useful - provide a practical benefit immediately, even if terraforming never happens.

• 🦺 Safe - pose no threat to potential Martian life, if it exists.

Today Pioneer Labs is announcing the first microbe we made for Mars. sPL.001 is an engineered bacteria that will use the nutrients in Martian dirt, water, and processed air to build the first city on Mars. We’ve also proven it is safe to send to Mars. Most importantly, this microbe eliminates a key risk on the path to terraforming: it confirms that Earth life can grow directly using the nutrients already present in the dirt on Mars, a key proof point toward the goal of greening the planet.

🌼 On the path to terraforming: growth is possible on nothing but Mars dirt (!)

Today, Mars is a planet-sized toxic waste site. It has the raw materials and nutrients needed for life in abundance, but they are mixed in the soil with toxins like perchlorate and salts that would make growth difficult for most living things. There are many proposals for growing plants on Mars, and they all involve some sort of remediation: rinsing the toxins out of the soil, bringing supplemental nutrients from Earth to fertilize soil, or giving up entirely on the outdoors and using hydroponics. These approaches don’t scale. If terraforming requires manually cleaning and fertilizing the soil, one robot at a time, over a planet with roughly the same land area as Earth it will be infeasibly expensive and time-consuming.

So, today we are announcing good news. sPL.001 can source all its nutrients, including trace elements, directly from Martian dirt, water, and processed atmosphere. It doesn’t require supplementation with fertilizer or pre-processing of materials to remove toxins! This is possibly the biggest way sPL.001 differs from other proposals for using biology in space, which rely on human poop, consumables from Earth, or substantial pre-processing of materials to support life. The resulting biomass is 100% genuine Mars atoms.

The result is that we have closed off an expensive branch of the roadmap for terraforming Mars. sPL.001 shows that, crucially and very specifically, what’s in the dirt isn’t going to be the dealbreaker! Much more remains to be done before we can grow living things outdoors on Mars. But using biology’s self-replicating power to scale to an entire planet remains on the table.

🪵 Useful: build a city of ‘log cabins’ with a single rocket

Humanity has never deliberately sent a living thing to Mars - human or otherwise. Doing so will involve enormous effort, money, and time. It also represents a big change in our approach to space exploration. The status quo is strong. To actually make it to Mars, the organism we engineer needs to offer enormous and immediate tangible benefits.

So, we engineered an organism that lets you build a city over 4 years by landing just one rocket on Mars. sPL.001 can be grown in a stirred, heated bioreactor that protects it from extreme temperature, radiation, and pressure on Mars. You feed the organism raw materials: Martian dirt, water, and processed air, which you have in infinite supply. As it grows, the organism produces bioplastics, which are a class of materials we’re familiar with in everyday life in many contexts: everything from compostable cups to 3D printing filaments are bioplastics. In a new paper, we found the terrestrial organisms that were the very best at this job and evolved them to be even better at using raw Martian nutrients to make more product — something that has never been done before. In another new paper, we built a complete analysis of the equipment you need to load into your spaceship so that you can grow these Mars microbes on Mars at massive scale and build safe, radiation-shielded, pressurized habitats - complete quantitative analysis of this sort of bioprocess has also never been done before.

The result is, essentially, a recipe for building the log-cabin equivalent for Mars: a safe type of dwelling for people that uses local resources, processed into final form by biology. With equipment that fits in a single rocket, you have everything you need to build a city if you work together with biology — an immediate benefit for bringing this microbe to Mars.

🦺 Safe: an organism that cannot become invasive by accident

4 billion years ago, when life was first evolving on Earth, Mars was a warm, wet planet that probably would have been friendly to life as we know it. For decades, we have explored Mars in the hopes that we can find evidence of life. Today, there is no solid evidence that anything is still alive on Mars, or that there ever was. But it will never be possible to prove a negative. There are ‘last places’ scientists want to check, including subsurface water and inside ancient salt crystals. The search will continue once humans are living on Mars, and it will improve with more access and better tools. The first time we send an organism to Mars on purpose, there needs to truly be no chance whatsoever that it could possibly become invasive and harm extant Martian life, if it exists.

So, we chose an organism that would be tremendously useful when fed by humans and grown inside a bioreactor on Mars, but that has absolutely no chance whatsoever of growing outside. We even measured just how dead this microbe would be if it escaped the confines of its bioreactor. sPL.001 is rapidly sterilized by exposure to the harsh conditions on Mars, especially the lack of liquid water. On top of that, we deliberately avoided using a photosynthetic organism that might be able to make its own food on Mars. If you don’t feed this organism processed Martian atmosphere in the form of acetate, it can’t grow. Evolution requires growth, so things that can’t grow won’t evolve into something more capable. We have a new paper that presents these data together with a proposed policy framework for evaluating the contamination risk of organisms that are sent to Mars in the upcoming era of human spaceflight.

The result is that even a full, catastrophic leak of an industrial-scale Mars bioreactor would still clear the planetary protection threshold by a factor of several hundred. These particular biomanufacturing organisms will be very dead, very fast if they get outside on Mars! sPL.001 is a useful tool for humans to use as part of living on Mars, but has no chance of terraforming Mars on its own. When humanity terraforms Mars, it’s important that it is on purpose, not by accident.

Read more

Want more technical details? Read more in three new papers:

• Paper #1: How we engineered sPL.001 using directed evolution. We found the terrestrial microbe that was closest to being up to the task, and evolved it to work better on Mars. Evolution continues to this day - stay tuned for further updates!

• Paper #2: How we tested if it is safe to send sPL.001 to Mars. sPL.001 stops growing if it escapes its bioreactor or you stop feeding it. Zero invasive species risk. In this paper, we use sPL.001 as an example to propose a policy framework called PRIM for how to assess biological risk on Mars more broadly. Read more about it or discuss in the comments of our previous blog post about planetary protection.

• Paper #3: How to use biomanufacturing to build a city on Mars. This paper presents a reference architecture for exactly how to pack your starship to build bioplastic structures on Mars.

What’s next?

The first microbe for Mars produces building materials from Martian dirt, water, and processed atmosphere. It is useful for building shelters, and safe to send to Mars. It is the first of five organisms we will need to make Mars green.