Synthetic biology innovations aim to change how we live on Earth. But could they also enable us to live on other planets? Scientists from iGEM teams to NASA are developing ways to make life off Earth a reality.Space has long captured the human imagination. We dream of living on other worlds and are inspired to tackle the challenges that come with it.Mars is our nearest potentially livable neighbor but the logistics of moving in are somewhat (extremely) complicated. Mars has lower gravity, higher radiation, few raw materials and a lack of breathable air. And those are just the local hardships. Making the trip with life’s literal necessities crammed into a rocket-sized suitcase presents its own set of hurdles.But Mars could be as liberating as it is limiting. On Earth, our cities are built up over hundreds of years, each generation adding on a new layer of technology and design. But the core systems and materials of our “habitats” are deeply entrenched and radically changing them is virtually impossible.Mars, however, is a blank slate. We can deliberately construct habitats to be more efficient and environmentally responsible. Lynn Rothschild, a senior research scientist at the NASA Ames Research Center, discussed Martian habitats at SynBioBeta’s annual conference. “Normal Earth companies need to show how their technology will benefit existing markets. Not true on Mars. There is no existing market system.” Essentially, there’s a lot less red-tape on Mars and therefore, more room to innovate.

The stage backdrop of SynBioBeta 2018, constructed by Ecovative Design from mycelium in a process that might not differ much from how we build space habitats. Photo courtesy SynBioBeta / Thomas Webb.

Which is one reason why Rothschild and her team have designed Martian habitats out of mushrooms.Utilizing mushrooms in biomaterials is a growing field on Earth. Companies like Ecovative are leading the way with mycelium-based foams, textiles and construction materials. Building with mycelia—known as myco-architecture, or mycotecture—could be ideal for Martian conditions.Mycelia are the root-like structures of fungi. Though fine and thread-like, they are pound-for-pound stronger than concrete and have a number of surprising capabilities.Mycomaterials are naturally fire-retardant, a critical component in sealed, pressurized, oxygen-rich habitats. They are also excellent insulators, again, very important on a planet where nightly temperatures can reach a nippy minus 73 C. And unlike many standard Earth materials, mycelia don’t give off toxic gasses.Another challenge of Martian living is radiation. On Earth, the melanin in our skin (mostly) protects us from the Sun’s harmful UV rays. But Mars’ thinner atmosphere and lack of a magnetic field make radiation exposure a serious problem. Melanin-rich fungi, however, are able to absorb radioactivity and could potentially create radiation-blocking structures. Rothschild also discussed bloating mycelial cells with water, making them “obese” under the microscope. In this case, the hydrogen atoms in the water would act as the radiation shield.Mycomaterials are clearly promising candidates for Martian construction. But we still have to get them there.Currently, according to NASA, every pound sent into space adds about $10,000 to the price tag. It’s financially impossible to deliver walls of mycotecture to Mars. Rothschild and her team have taken this into account.

Graphic depiction of Myco-architecture off planet: growing surface structures at destinationCredits: redhouse studio, 3d tour available here. L. Rothschild

Their idea is to seed a flexible plastic shell with mycelial spores and dried feedstock. Upon arrival, the shell would be configured into the structural frame of a human habitat. Water (either from Earth or Mars) and heat would be added into the shell, prompting the spores to wake up and eat the feedstock. The feasting mycelia would release oxygen which, in turn, would inflate the mycelia-enforced frame. Once the mycelia have consumed all their feedstock, they would go back into hibernation. If repairs or additional structures are needed, the mycelia could be reactivated with more feedstock, water, and heat.Rothschild also discussed mixing mycelia with Martian regolith, the planet’s rocky top layer. Experiments show that mycelia enhance regolith, making it a more flexible and ductile building material. Mycomaterials are currently being tested as bricks and even fungal glues.NASA certainly aren’t the only ones thinking around Mars’ lack of raw materials or the hefty inter-planetary transport costs. With these limiting factors in mind, everything on Mars becomes a potential resource, including, well, waste.The 2017 gold medal Calgary iGEM team took waste management as an opportunity to solve a number of problems simultaneously. Obviously, humans on Mars are going to produce waste. But then what do you do with it? Storage becomes a significant issue, as does environmental pollution. The best solution is to recycle it and turn it into something useful.That’s what Calgary team thought when they created Astroplastic, a bioplastic made from upcycled human waste. The idea may sound squeamish at first, but practically speaking, it makes a lot of sense.Calgary team member Amy Chen joined Rothschild at SynBioBeta 2018 to discuss the process behind Astroplastic. The team engineered E.coli cells to secrete PHB, a biodegradable polymer. PHB is analogous to petroleum plastics in terms of its functional characteristics but comes without the downside of environmental damage. Astroplastic can be used to easily and cheaply 3D print tools or parts.

The University of Calgary's iGEM 2017 project involves using genetically engineered E. coli to turn human waste into bioplastics.

The ability to easily make tools or repair materials is pivotal on long space voyages. Chen described going to Mars like going on a 50 million km camping trip. If something breaks, it’s not really possible to stop at Home Depot. And then there are the unanticipated needs, things no one realized they would need until they got there. NASA does a good job thinking through many potential scenarios, but Martian life is completely new territory. Astroplastic printing could turn a packing list error from a critical mistake to a minor inconvenience.Biomaterials are the way of the future. They are functional, environmentally responsible, and sustainable. And because they are bio-based, they have the potential to self-grow and self-repair. Though we are struggling to rapidly scale up our use of sustainable biomaterials on Earth, Mars gives us the opportunity to start from scratch. Space travel has improved our lives with innovations we often take for granted, including water purification systems, smartphone cameras, and laptops. Perhaps, in our continued reach for the stars, biomaterials will integrate themselves into our Earthly lives as well. Maybe, one day, it will be hard to imagine we had ever lived differently.