Last month Erika DeBenedictis, CEO of the nonprofit start-up Pioneer Labs, delighted or shocked many space nerds with some big news: she and her colleagues had engineered \u201cthe first microbe for Mars.\u201d<\/p>\n
In a post on X<\/a> that has garnered more than two million views, DeBenedictis claimed that her bacterium, a tweaked version of Cupriavidus necator,<\/i> represents \u201cthe first step towards terraforming\u201d the Red Planet. By seeding Mars with microbial life, she has argued, we can make the world more Earthlike from the ground up.<\/p>\n \u201cEverything life needs to thrive is given to us by nature,\u201d observed DeBenedictis, a synthetic biologist with a Ph.D. from the Massachusetts Institute of Technology, in a slick promotional video that was included with the post. \u201cWhen humanity goes to space, we have to bring nature with us.\u201d The clip teased a future Mars with green valleys and self-sufficient, see-through, domed habitats, all constructed with locally sourced materials, some of them courtesy of the microbe, which DeBenedictis and Pioneer Labs call \u201csPL.001.\u201d<\/p>\n If you’re enjoying this article, consider supporting our award-winning journalism by subscribing<\/a>. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.<\/p>\n It\u2019s certainly a compelling story. And it\u2019s backed up with a few recent preprint papers detailing Pioneer Labs\u2019 research. But how much of it is fantasy?<\/p>\n Scientific American<\/i> put that question to several researchers working at the intersection of planetary science, astrobiology, microbial ecology and bioengineering\u2014and their responses are, on the whole, fairly positive. The most critical assessment comes from Chris McKay, a planetary scientist at NASA\u2019s Ames Research Center, who has studied terraforming for decades. McKay is senior author of \u201cThe Case for Mars Terraforming Research,\u201d a paper<\/a> led by DeBenedictis that was published last year in Nature Astronomy<\/i>. The engineered bacterium is \u201cnot very interesting, not very new yet,\u201d he says. \u201cI hope better is coming soon.\u201d Paul Race, who studies industrial biotechnology at Newcastle University in England, offers the same impression, calling the announcement \u201crather over the top.\u201d<\/p>\n Their core qualm is that this microbe alone can\u2019t bring a dead planet to life. \u201cThis microorganism, sPL.001, is not for terraforming Mars\u2014it\u2019s for making feedstock for 3D-printed houses,\u201d McKay says. \u201cIt can only be grown in a bioreactor,\u201d an apparatus for incubating microbes, such as yeast, to yield useful by-products. DeBenedictis\u2019s microbe would pump out a form of bioplastic by consuming Martian dirt, water and compressed carbon dioxide delivered to the bioreactor with autonomous machinery. To her credit, DeBenedictis has been clear on this point: sPL.001 \u201cis the first of five organisms we will need to make Mars green,\u201d she wrote in an post<\/a> on Pioneer Labs\u2019 Substack.<\/p>\n \u201cHopefully,\u201d McKay says, \u201csome of the other four are green and can actually grow on Mars!\u201d<\/p>\n A workbench at Pioneer Labs\u2019 headquarters in Emeryville, California. This equipment uses robotics for high-throughput characterization of evolved microbes in search of ones suitable for Martian environments.<\/p>\n Elijah Collins\/Pioneer Labs<\/p>\n<\/figcaption><\/figure>\n DeBenedictis founded Pioneer Labs in 2024, when she was a resident at the San Francisco Bay Area\u2013based Astera Institute, a billionaire-backed nonprofit focused on incubating science and technology projects with ambitious long-term visions (and correspondingly ambitious needs for sustained funding). The company\u2019s name, DeBenedictis says, comes from the ecological idea of \u201cpioneer species\u201d that colonize barren territory as a first step for the creation of complex ecosystems. And its stated goal is no small thing: to make the universe more friendly to life.<\/p>\n On Earth, pioneer species are usually organisms we think of as weeds or pests that can tolerate the harshest environments: molds that feast on decaying organic matter, lichens that thrive almost anywhere or dandelions that grow in and break up rock to make and enrich soil. They\u2019re not glamorous, but they allow \u201cfancier organisms and shrubs and trees and stuff to grow, and that\u2019s exactly what we\u2019re trying to do\u201d for Mars, DeBenedictis tells Scientific American<\/i>.<\/p>\n Bootstrapping a biosphere there isn\u2019t easy, however. Biology is bedeviled on the planet, exposed as it is to unrelenting harmful radiation and given its paltry atmosphere, 1 percent as thick as Earth\u2019s, and temperatures that, in a single Martian day, can swing violently by 100 degrees Celsius. The low levels of nitrogen in the atmosphere and in the ground add insult to injury\u2014a 2025 review paper<\/a> in Communications Biology <\/i>noted that a lack of nitrogen is \u201ca major limiting factor for establishing Earth-like organisms or supporting human agriculture, and limits our capacity to terraform the planet.\u201d Plus, some samples of Martian soil contain high levels of perchlorates, toxic chemical compounds, also found in rocket fuel, that could potentially poison the planet\u2019s supplies of water and food.<\/p>\n \u201cWe need to choose carefully\u201d when we devise bioengineered microbes to overcome these immense challenges, DeBenedictis says.<\/p>\n Neveda Naz, an astrobiologist at Tufts University, who has grown microbes in material from Martian meteors, says Pioneer Labs had done just that with its focus on the bioplastic-producing version of C. necator<\/i>. \u201cThey have picked an organism, adapted it to a defined Mars-relevant chemical environment and demonstrated improved production of a useful material,\u201d Naz says. \u201cIf the goal is eventually to manufacture materials off-Earth using predominantly local resources rather than transporting everything from Earth, that\u2019s a very worthwhile and smart direction to explore.\u201d<\/p>\n Alexandre Rosado, a microbiologist who has studied terraforming and focuses on ultrahardy microbes called extremophiles, agrees. \u201cI think the work is interesting, and there is certainly good science there,\u201d he says. \u201cI would not dismiss it. My view is that microbes will almost certainly be part of any serious attempt to use local Martian resources or, much further down the road, modify Martian environments.\u201d<\/p>\n Both Naz and Rosado, however, quibble with Pioneer Labs\u2019 declaration that this makes the modified C. necator <\/i>a \u201cmicrobe for Mars.\u201d For Rosado, the company\u2019s language around terraforming \u201cgoes quite a bit beyond what they have actually demonstrated.\u201d And, Naz says, \u201cthere is an important distinction between showing that Martian regolith can provide biologically useful nutrients and showing that an organism can grow in the Martian environment.\u201d<\/p>\n DeBenedictis is aware of the distinction\u2014it\u2019s the centerpiece of Pioneer Labs\u2019 safety strategy for avoiding potentially ruinous interplanetary contamination, PRIM (Propagation Restricted, Inert on Mars). In her team\u2019s experiments, the researchers found that C. necator <\/i>failed to reproduce if it was starved of water and carbon. So, she says, if the microbe somehow escaped a bioreactor on Mars, its chances of survival and reproduction would be infinitesimal. \u201cEven a full, catastrophic leak of an industrial-scale Mars bioreactor would still clear the planetary protection threshold by a factor of several hundred,\u201d DeBenedictis says. \u201cI\u2019m genuinely not worried about it.\u201d<\/p>\n Whether policymakers who set international standards for \u201cplanetary protection\u201d protocols won\u2019t worry about it, either, is another hazy aspect of Pioneer Labs\u2019 hopeful aspirations. Without regulatory approval, DeBenedictis\u2019s best-laid plans for helping to terraform Mars may literally fail to launch. As NASA administrator Jared Isaacman noted on X<\/a>, however, his team has been working<\/a> to revise the space agency\u2019s protection policies to align them with what he calls the \u201ccommon-sense principles\u201d originally established in the \u201cearly days of planetary exploration and later reflected in Article IX of the Outer Space Treaty.\u201d He thinks current protection policies needlessly add \u201cextreme cost and time to robotic missions to Mars when the overarching goal is to send astronauts there as quickly and safely as possible.\u201d<\/p>\n Ricard Sol\u00e9, a biologist who heads the Complex Systems Lab at Pompeu Fabra University in Barcelona and studies, among other things, terraforming via bioengineered ecosystems, thinks PRIM is on point. \u201cIt separates useful biotechnology from uncontrolled ecological spread,\u201d he says. \u201cPioneer Labs\u2019 proposal is a very interesting and important step, but if the goal is eventually to build a stable, closed ecology on Mars, then a systems-level perspective will be essential.\u201d Mars will need more than \u201ca single engineered strain,\u201d Sol\u00e9 says, envisioning a larger assemblage of multispecies communities that collectively recycle matter, turn one organism\u2019s waste into another\u2019s resource, regulate environmental conditions, and so on. \u201cIn that sense,\u201d he says, \u201cthe challenge is not only to engineer organisms but to engineer the ecological interactions that allow the whole system to sustain itself.\u201d<\/p>\n This is where DeBenedictis\u2019s as-yet-unannounced four other microbes come in. They have yet to be revealed, she says, because Pioneer Labs hasn\u2019t entirely settled on which organisms could do the job. Whichever ones win the day will have to offer \u201ctransparent building materials, perchlorate reduction, making fertile soil, and then food and oxygen,\u201d she says. The transparent material, crucial for making windows, will be the hardest to find, she speculates. \u201cWe don\u2019t have very many examples of biomaterials that are transparent when they\u2019re dry, which is what you need on Mars because the atmosphere outside will dry anything out, so we\u2019ll see what we come up with.\u201d<\/p>\n If all goes to plan, she thinks, the effect will be to transform the night sky by a significant smidge. \u201cYou can see Mars outside with your naked eye, and it\u2019s noticeably a little red relative to other stars in the background,\u201d she says. \u201cAnd I think, before I die, I\u2019ll get to see it be a little bit green.\u201d<\/p>\n<\/div>\nOn supporting science journalism<\/h2>\n
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