Biomimicry and biotechnology for space systems: from macro to micro

In space technology, engineering, and design, the concept of biomimicry – utilizing biological solutions to solve complex problems - is not a novel approach. There is ongoing research on biology-based enabling technologies for human space exploration (Rothschild Reference Rothschild2016). The V.I.N.E. group (Virtual Interchange for Nature-Inspired ExplorationFootnote ² ) at NASA’s Glenn Research Center and the Advanced Concepts Team at the European Space Agency (ESA) (Menon et al. Reference Menon, Ayre and Ellery2006) are working on several projects using biomimicry for space applications. Some of their work explores tensegrity robots, seal whisker-inspired sensors, foldable and deployable solar panels gecko grippers and sensors based on a fly’s eye. Other examples of biomimicry in space include cyanobacteria-based life support systems (Verseux et al. Reference Verseux, Baqué, Lehto, De Vera, Rothschild and Billi2016) and the European Micro-Ecological Life Support System Alternative (MELiSSA) project (Vermeulen et al. Reference Vermeulen, Papic, Nikolic and Brazier2023). The MELISSA project is a bioregenerative ecosystem that is inspired by lake ecosystems (Walker and Granjou Reference Walker and Granjou2017).

During the symposium, many presentations included research on biomimicry particularly in the area of materials engineering. Specifically, the use of biomaterials and the concept of Engineered Living Materials (ELMs) for space applications were presented. Biomaterials as described here are grown, rather than manufactured, and examples include fungal mycelium, bacterial cellulose, plants, and animal cells. ELMs are materials inspired by nature that self-synthesize, sense, and respond to the environment and are hierarchically structured (Molinari et al. Reference Molinari, Tesoriero and Ajo-Franklin2021). ELMs contain living elements that provide the responsive function and polymeric matrices, required for scaffolding functions, and can therefore be designed as active and responsive materials (Nguyen et al. Reference Nguyen, Courchesne, Duraj-Thatte, Praveschotinunt and Joshi2018; Rodrigo-Navarro et al. Reference Rodrigo-Navarro, Sankaran, Dalby, del Campo and Salmeron-Sanchez2021).

In addition to ELMs, non-living biomaterials were also presented and discussed. For instance, biomimetic composites akin to natural seashells or pearls could be produced through the low-energy hybridization of natural biopolymers and extraterrestrial mineral deposits. These biopolymers could be generated through versatile bioreactors, where phototrophic microorganisms could be engineered to produce binders through the fixation of CO₂ and N₂ with sunlight. The notion of considering inhabitants as bioreactors was also discussed; here a protein from human blood (Human Serum Albumin) could be combined with urea (obtainable from urine) and regolith to produce a biological composite with compressive strengths on par with terrestrial concrete (Roberts et al. Reference Roberts, Whittall, Breitling, Takano, Blaker, Hay and Scrutton2021).

These biomaterials, and especially ELMs could potentially play a crucial role in the future of space systems due to their unique properties. These include self-replication, self-healing and self-assembly processes, without the need for high-energy or resource-intensive processing. These processes could significantly lower the costs of a mission since the desired materials and objects can be grown in situ, reducing the mass of material needed to be transported from Earth. The self-healing properties and the possibility to create on-demand materials also provide a source of reliability, flexibility and safety. The second property of note is responsiveness to the environment. As such biomaterials are able to sense changes in the environment and respond to them with minimal energy and material cost (Pawlyn Reference Pawlyn2016; van Ellen et al. Reference van Ellen, Bridgens, Burford, Crown and Heidrich2023). The third property advocating for the use of biological materials in space systems is their innate potential for multi-functionality. A variety of functions and properties can be embedded in the materials, based on the given requirements and mission needs and intrinsic weaknesses of selected materials can potentially be overcome through methods such as bioengineering and synthetic biology; techniques which could be conducted in situ to provide flexibility and reduce mission risk (Gilbert and Stephens Reference Gilbert and Stephens2018; Tang et al. Reference Tang, An, Huang, Vasikaran, Wang, Jiang, Lu and Zhong2021). Different techniques and processes were presented during the symposium including using enclosed environments and molds to grow organisms and additive manufacturing to develop bulk materials. However, notably absent from the discussions was the utilization of 3D bioprinting, an emerging technology that enables rapid assembly of tissue-engineered constructs in three dimensions (Correia Carreira et al. Reference Correia Carreira, Begum and Perriman2020). We suggest that incorporating the topic of 3D bioprinting into future symposia could enrich the discourse and enable to bridge between processing and manufacturing of bulk materials and scaffold materials with biomaterials.

The ideas discussed during the sessions on Mycelium for Mars and Novel Biotechnologies for Space Habitats of using biological materials and ELMs include growing space habitats and creating habitats as living habitation systems. For example, during one presentation it was suggested that mycelium could be embedded into the habitat structure itself and utilized as a form of biosensor in the detection of temperature, oxygen and pressure changes in the habitat. Such a solution would enable the creation of a habitat that could respond and adapt to its environment, and cohabiting astronauts (Brandić Lipińska et al. Reference Brandić Lipińska, Maurer, Cadogan, Head, Dade-Robertson, Paulino-Lima, Liu, Morrow, Senesky, Theodoridou, Rheinstädter, Zhang and Rothschild2022). Other potential research avenues discussed included the utilization of biological organisms in space for the bioproduction of essential or useful commodities, such as food, bioplastics or bespoke pharmaceuticals on demand.

The use of microorganisms through bioengineering and synthetic biology also provides the potential to create flexible bioreactors to sustain habitation and life on the Moon and Mars. For example, an iGEM student-led project from the Exeter team in 2018 explores if bioreactors containing specific microbial strains could be used in the production of oxygen from the Martian regolith, which in turn are also able to detoxify the regolith from the harmful perchlorates contained within.Footnote ³ Regolith is one of the most readily abundant in situ materials found on the Martian surface, and therefore one of the best candidates for the construction of off-world habitats (Liu et al. Reference Liu, Li, Sun, Guo, Harvey, Tang, Lu and Jia2022). Several methods have been proposed for the mechanical stabilization of regolith and include heat-fusion (sintering), cement composites (concrete), synthetic polymer binders, sulfur binders and fusion with ice (Naser Reference Naser2019; Naser and Chen Reference Naser and Chen2021). However, these solutions have several drawbacks, such as high energy or water use, or the need for the mining, purification and processing of specific mineral deposits – which would constrain habitat locality and add to launch mass and mission cost. By utilizing living organisms for planetary construction, it could however be possible to create regolith biocomponents, where the bound material would grow in situ. Examples include proteins and carbohydrates for the creation of regolith biocomposites (Roberts et al. Reference Roberts, Whittall, Breitling, Takano, Blaker, Hay and Scrutton2021; Roedel et al. Reference Roedel, Lepech and Loftus2014), or the use of mycelium for consolidation of the regolith into structural components. Presentations also suggested humans themselves be considered as in situ resources, as they too are able to produce, a variety of organic compounds, including urea, and Serum Albumin, both of which could be used as binders for regolith (Roberts et al. Reference Roberts, Whittall, Breitling, Takano, Blaker, Hay and Scrutton2021).

Mycelium-based materials

The use of mycelium – the vegetative, root structure of fungi – was primarily discussed during the Mycelium for Mars session. However, it was not limited to that session only, in fact, concepts or projects using mycelium for a variety of purposes in space exploration were repeated throughout the whole symposium. The Mycelium on Mars session was also not restricted to the Martian environment; it covered the wider context of using mycelium-based material for space exploration, at different feasibility levels and over varying time scales.

Mycelium is one of the emerging biomaterials that has a variety of beneficial, current, and prospective properties. It can even be bioengineered to provide additional properties and functions. Commercial applications (fashion, packaging material, acoustic panels, decorative furniture, or insulative material) are starting to gain traction on the market with the existing fabrication methods constantly being improved upon through ongoing research. Some examples were shown of mycelium products already at high technology readiness level (TRL). Companies like Ecovative, Bolt Threads, or Biohm lead the fungi food and biomaterials revolution with mycelium-based materials. Ecovative has licensed their Mushroom@Packaging technology in the US and around the world in the last few years, and more recently Stella McCartney partnered with Bolt Threads on a limited run of 100 mycelium-crafted bags that sell for up to $2950 (Biohm, n.d.; Bolt Threads, n.d.; Ecovative 2022). Because of the favorable properties and characteristics it exhibits (see the next section for detailed overview of these properties), there is extensive, ongoing research on integrating mycelium into the built environment (Elsacker et al. Reference Elsacker, Peeters and De Laet2022a, Reference Elsacker, Van Rompaey, Peeters and De Laet2022b). Consequently, it has also been proposed as a material for applications in space habitats, adding to the pallet of space-architectural solutions.

Mycelium-based materials and the idea of growing structures in situ are being considered both as a new construction approach for building space habitats and as an alternative for creating furnishings and interior elements inside the habitat, in a controlled environment.

The main properties in favor of using mycelium-based materials are its insulative, acoustic, and fire resistance properties, the ability for waste-degradation and self-healing and self-replicating potential. The use of mycelium also contributes to the efficiency of material transportation. In terms of utilizing mycelium for outer space architectures, with the possibility to grow materials in situ, there is no need to launch quantities of construction materials, decreasing the mass of the payload. Instead, what needs to be brought from Earth are spores and some nutrients, enabling the formation of components in situ.

In addition to the building efficiency, another potential advantage of utilizing mycelium for outer space architecture and living systems could address human psychological factors of sustained space travel, for example enabling astronauts to outfit their environments with mycelial components. We envisage that the different textures of various mycelium-based materials have a great level of tactility. Indeed, some studies suggest that tactility may be beneficial for the psychological comfort of astronauts (Schlacht Reference Schlacht2012).

Additionally, certain mycelium species are also edible, could have medical applications (within the development of cancer therapeutics) (Patel and Goyal Reference Patel and Goyal2012), and could also provide radiation protection (melanin-rich fungi) (Mattoon et al. Reference Mattoon, Cordero and Casadevall2021). Other species are bioluminescent and can sense temperature, pressure and other chemical and physical differences (Adamatzky et al. Reference Adamatzky, Gandia and Chiolerio2021). There are myriad possibilities for the application of mycelium-based materials in architecture and space habitats. Therefore, many visions and scenarios are being researched spanning a large feasibility scale on how fungal-based materials can benefit human habitation in space: from arrival, to resources and infrastructures, to environmental adaptation and communication. Scenario methods are discussed in more detail in Speculative approaches and scenarios section.

The Mycelium for Mars session not only discussed the opportunities and potentialities of using mycelium but also the trade-offs and challenges that would be necessary to overcome in order to develop the vision into prototypes and architectural materials and components. During the talks, it was explained that the material functionality is dictated by the fabrication process. Growing mycelium is a resource-intensive process. It needs life-supporting conditions: the presence of oxygen, stable temperature, H₂O, a humid environment and nutrients (usually plant husks or cellulose-based structures). Additionally, a lot of heat is required to bake the mycelium, to prevent further, uncontrolled development and creation of fruiting bodies. Therefore, there is a trade-off in terms of the amount of equipment and resources required for processes that provide the strength and functionality of materials.

Understanding the system metabolism is critical for the development of efficiently functioning space habitats and living habitation systems. It includes mapping of the specific waste streams: gas and water quantities required for synthesis as well as the end-of-life scenario in terms of how used mycelial elements could be broken down into new components. To be able to efficiently use mycelium for space applications, we need to maximize resource efficiency within the system’s metabolism. One of the proposed solutions was the integration of waste streams into the growth process (Brandić Lipińska et al. Reference Brandić Lipińska, Maurer, Cadogan, Head, Dade-Robertson, Paulino-Lima, Liu, Morrow, Senesky, Theodoridou, Rheinstädter, Zhang and Rothschild2022) such as recycling of water from the drying process.

In addition, adapting an ecosystem-based approach (material ecology), is to use the most abundant resource on the Moon or Mars – regolith. Despite the fact that mycelium-based composites have a great advantage in growing into bulk materials in a short period of time, to achieve the scale for human habitat, extra aggregates could significantly reduce the nutrient and time requirements. Although mycelium cannot grow solely on regolith, the regolith could provide a structural mass, and with minimum quantities of nutrients, mycelium can act as a binder, holding the regolith-based structure together (Brandić Lipińska et al. Reference Brandić Lipińska, Maurer, Cadogan, Head, Dade-Robertson, Paulino-Lima, Liu, Morrow, Senesky, Theodoridou, Rheinstädter, Zhang and Rothschild2022).

There is still a substantial gap between commercially ready products and current fabrication methods of mycelial products and those that are required or desired for space-architectural applications. A stepping stone is needed between our current capabilities and the future mycelium-based space habitats, that are more achievable in the coming decade. The discussion around this topic led to questions about near-term mycelium applications for space. Some research questions are:

• Which additional applications can we research to enable us to test and validate the utility of mycelium in actual off-world conditions?

• How can we grow (mycelium) using minimal biomass and/or water and oxygen?

• How can we ensure the long-term robustness of the materials in extreme conditions?

• What are the construction methods that would enable minimal interventions in the habitat construction and maintenance process?

• Is it possible to create real self-replicating and self-healing habitats?

Relations with the natural in space

A more permanent human presence in deep space, invites crucial discussions around the role of nature in sustaining human life, as well as the impact on well-being of humans on future deep space journeys, and the creation of livable habitats on other planets that support human and nonhuman life in the long term (Imhof et al. Reference Imhof, Weiss, Vermeulen, Flynn, Hyams, Kerrigan, Rengifo, Mohanty and Armstrong2017). Human relations to the Natural are not only reflected upon within the Anthropocene, but further in relation to the nonhuman world. The nonhuman world is comprised of other-than-human living organisms (animals, microorganisms, fungi, etc.), the non-living and the various ecosystems present both on and off-world.

Diverse art, design, and science projects presented at the symposium showed the relevance of the biosocial perspectives with interdisciplinary and transdisciplinary projects that studied perspective shifts from human-centric to polycentric. Polycentric being the inclusion of humankind’s interconnectedness with the Natural, remediation of nature in the Anthropocene and in extreme environments, life-like reproducing AI systems able to create human habitats, and human-AI interdependence in future scenarios.

Humankind’s relation to nature on and off Earth has been shown to be highly influenced by human-centric perspectives (Fremaux Reference Fremaux2019). Past research into the creation of off-world human-made habitats included the design of controlled biospheres that are highly selective in choice of species and ecosystems, excluding what is considered undesirable and non-serving to humans (Tsiolkovsky Reference Tsiolkovsky and Groys2019). This thinking has been continued into the more recent MELiSSA and Lunar Base 1 projects (Walker and Granjou Reference Walker and Granjou2017). During the symposium, participants were speculating on ‘What is nature in space?’.

When humans bring living systems into otherwise controlled environments these systems have an ambiguous nature as they could either represent “nature” or the human control of it (Bringslimark et al. Reference Bringslimark, Hartig and Patil2009). What might be considered “nature” depends on the extent to which the living systems are allowed to evolve and adapt to new environments, and to what extent we adapt and control the environment itself. Therefore, questions about human relations emerged throughout the symposium during talks and discussions, some of which will lead to future research. For example, is it a human-created and/or controlled nature? Is it designed as an evolving system that develops in relation to factors such as human behavior, environmental resource availability and environmental changes? Can these evolving systems begin to create their own nature?

Research and artistic projects questioned the past perspective of a controllable nature and invited to be inspired by the human-caused Anthropocene to take new pathways toward complexity and inclusive futures of human existence also in space. Diverse artistic projects are exploring the remediation of Anthropocene environments by codesigning with living organisms. For example, mycoremediation has been shown to successfully detoxify soil through fungal metabolism (Assad et al. Reference Assad, Rafiq, Bashir, Sofi, Reshi and Rashid2021). Following that natural process, fungal-based burial suits were presented as a potential study for the use of human bodily wastes as part of a circular system that could be utilized within more extreme environments (Nai and Meyer Reference Nai and Meyer2016).

Presentations and discussions at the symposium highlighted explorations into codesigning and interfacing to drive polycentric perspectives. They showed that the nonhuman world can inform, inspire, and drive research into travel and habitation in space toward healthy systems that coexist in a sustaining and evolving modality.

Specific projects addressed these relations through collaborations such as the Human-Bacteria Interfaces which were presented during the symposium. This project, also presented in Albrecht et al. (Reference Albrecht, Boelen, Pelluchon and Weibel2023), was specifically looking at microbe-human relations and the potential for one to interface with the other, potentially leading toward mutualistic symbiotic modes of being. It aimed to de-center human agents and allow for a disassembly of established narratives of bacteria and microbes as inherently bad or harmful in their existence of highly complex, de-centered ecosystems. Ideation and prototype development were led by assessment of the ways in which microbial organisms sensorily and habitually engage with their surroundings, making potential nonhuman narratives part of the design and knowledge process. The designed interface used bacterial cellulose as a living medium to facilitate human-microbial interaction. In a modular structural system made from bacterial cellulose, textiles and glass, the interface allows for mutualistic cocreation of experimental architectural structures. The structure cohosts humans and bacterial cellulose in an ever evolving, growing manner that is activated through signaling and supply of nutrients and shelter.

Vermeulen presented that growing and evolving habitats, especially in the context of spaceships, offer the potential of using so-called emergence engineering, a form of bio-inspired engineering that translates the behavior and systems of living organisms into an evolving form (Gorochowski et al. Reference Gorochowski, Hauert, Kreft, Marucci, Stillman, Tang, Bandiera, Bartoli, Dixon, Fedorec, Fellermann, Fletcher, Foster, Giuggioli, Matyjaszkiewicz, McCormick, Montes Olivas, Naylor, Rubio Denniss and Ward2020). Self-replicating spaceship modules that are programed with rules of termite architecture in relation to human spaceship population numbers were presented as example (Imhof et al. Reference Imhof, Weiss, Vermeulen, Flynn, Hyams, Kerrigan, Rengifo, Mohanty and Armstrong2017). In a system using de-centralized swarm robotics, the modular spaceship system can source material to replicate from its environment to build an exponentially growing spaceship architecture that allows for replacement of the modules and metamorphic evolution of the overall system through a combination of growth, repair, replication and evolution. In scenarios that envision such self-replicating architectures for human habitats, a factor that needs to be considered is balancing human occupancy in relation to the dynamic habitat structure. The life-like property of self-replicating spaceships and the relation to human reproduction invites the study of a nonhuman perspective of future habitat creation and codependency.

These projects challenge design and technology interventions that aim to facilitate a world of self-sufficiency for humans from the more-than-human world; and emphasize our interdependence and interconnectedness within a complex system of nature. The projects aim to move beyond the human-centric idea of nature as an object to be controlled, tamed or mainly evaluated or included based on its value to us. The ever-evolving human relation to the natural on Earth and in space will continue to be challenged by sociocultural perceptions and ever-evolving technological possibilities. However, the presented projects drive futures that move beyond the narratives of what nature should be, based on human-centric ideas and the control of the nonhuman as humanity moves closer to establishing a permanent presence off-world (Mads Bering Christiansen et al. Reference Christiansen, Beloff, Jørgensen and Emilie Belling2020).

Systems thinking

Throughout the whole symposium, emphasis was placed on the need for interdisciplinary and transdisciplinary methods to develop bio-futures. The guest panelists also emphasized the need to work together with industrial partners and policymakers, going beyond purely academic thinking. Even though, as one panelist pointed out “people are naturally territorial about the stuff they know and the stuff they do”. However, working together is about unlocking the collective intelligence of the group (Vermeulen et al. Reference Vermeulen, Nevejan, Brazier and Boelen2018). This process will require facilitation, however, and needs to be economically viable, which is not always the case in academia.

Working across fields is difficult to achieve (Verkerke et al. Reference Verkerke, van der Houwen, Broekhuis, Bursa, Catapano, McCullagh, Mottaghy, Niederer, Reilly, Rogalewicz, Segers and Verdonschot2013) but one way to enable this transdisciplinarity is to utilize systems thinking. Systems thinking can be defined as “a practice of seeing wholes and a framework for seeing interrelationships rather than things, for seeing patterns of change rather than static snapshots” (Senge Reference Senge1994). There are different ways to approach this (and different scales) but there was an overall consensus of viewing transplanetary habitats as large dynamic systems, that encompass all subsystems within, such as the structural system, ECLSS (Environmental Control and Life Support Systems), power, logistic supply, communication, and data handling. Creating dynamic transplanetary habitats is crucial in highly unpredictable environments (Vermeulen et al. Reference Vermeulen, Goldoust, Sirenko, Hallak, Lutkewitte, Husárová, Long and Brazier2019). It increases the overall adaptability and resilience of the habitats over time. Such an approach includes conceiving the ECLSS as a bioregenerative system with dynamic and potentially evolvable properties.

During the panel session, an important distinction was mentioned: optimizing a system vs. satisficing a system (the latter being a combination of the words satisfy and suffice). Following in the tradition of the scientific method, in which we investigate variables in isolation, often subsystems are designed for optimization of a single parameter under pre-defined conditions, but at some point, we will have to satisfy a whole environment (Mankiewicz et al. Reference Mankiewicz, Hénaff and Dyson2021) in which performance variables interact with and are interdependent on each other (Levin and Emmerich Reference Levin and Emmerich2013). This means preferring a system that isn’t optimized for any one function but that has multiple pathways to solve problems at the same time, much like cell metabolism. Such redundance increases the resilience and longevity of a system.

Another important notion is that of systems integration – the consolidation of numerous distinct systems into one to simplify processes and reduce complexity. Systems integrations were presented holistically but also starting from a specific case or challenge such as using byproducts of chemical reactions. For example, fuel cells that convert hydrogen and oxygen (available as rocket propellant), into electrical power with the by-product being pure water available for drinking – is far more efficient than separate propellant, energy storage (e.g., batteries), and water storage systems. Having heavily integrated systems also reduces the need for backup systems and spare parts for redundancy, since a failure of one system could be mitigated by others. Biological systems could integrate numerous systems and provide many benefits that would reduce mission complexity, launch mass, cost, and overall risk. For instance, a versatile algae photo-bioreactor system could not only produce food and oxygen highly efficiently (negating the need for a separate oxygen production system and associated back-ups), but the organisms could also be engineered to produce bioplastics, bioadhesives, or other useful chemicals or pharmaceuticals as required. Instead of needing to take every medicine that may be needed on a mission (with resupply for long-duration missions as medicinal efficacy degrades over time), bioreactors could produce pharmaceuticals as required - in addition to their other useful functions.

Speculative approaches and scenarios

Many approaches to the presented research were speculative, and science fiction was often quoted as inspiration to imagine possible futures in space. The methods – originating from the design approach – to develop these visions and turn them into concepts (and eventually high TRL applications) are (Hyry Reference Hyry2021):

• Scenario building and speculative design.

• Material experimenting and rapid prototyping.

• Observing results on the small scale before going to larger scale to avoid failing in the very early stages of the process.

• Bottom-up approaches.

• Computer simulation.

These speculations were sometimes more defined using scenario theory and the Futures Cone. The Futures Cone is able to define and detangle futures from each other by categorizing them into futures that are: preposterous, possible, plausible, the “projected” future, probable and finally preferable future (Voros Reference Voros2017). Speculative design critically examines the future and not only prepares for preferable futures but also the undesirable, unexpected and unbelievable futures (Voros Reference Voros2017). It is a way to open up the thinking process and suggest another way of looking at the future from various perspectives and to raise questions about them.

With the help of future scenarios, the desired future can be built with existing tools and materials. Future scenarios also prepare humans to confront the obstacles they may experience on their way to space and observe the critical turning points.

One way to develop those scenario’s is to experiment with materials and learn from those experimentations as one presenter highlighted. It was explained that material experimentation is a way to deepen the understanding of the material behavior and understand the properties which leads to exploring all the possible usages and create more in-depth future scenarios. The hands-on material exploration process is more about learning through the failures that happen during the development process as the material does not react as planned.

These scenarios were developed and presented by architects and designers showing through drawings and collages the possible future scenarios for life in space. Some presenters also tried to simulate how these futures will evolve with computer models. For example, there were talks about simulating the development and evolution of a spaceship during decades of deep space travel, but also simulations of social species interactions such as ants, bees, and termite colonies.

Considerations – biosafety and bioethics of space exploration

Space exploration, and especially human spaceflight, has always raised questions about its ethics (Chon-Torres Reference Chon-Torres2017). Do we, as a species, need to venture beyond Earth’s atmosphere? Do we have the right to settle on other planetary surfaces? And if we bring along living organisms, how do we deal with the lack of consent? Furthermore, there is the additional concern of biosafety, as organisms may manifest and evolve novel traits in space, potentially introducing unforeseen biological hazards to both human and nonhuman life forms. Synthetic biology is often touted as a solution to adapt organisms to the unique conditions of outer space, but even here on Earth there is no consensus yet on how to release such organisms in the environment.

It’s clear that in parallel with developing bio-inspired technologies, we need to equally develop a robust bioethical framework. Researchers in the emerging field of astrobioethics argue that a critical aspect of exploration is to reflect on our past and explore consciously, going beyond biological safety to include moral reflection (Chon-Torres Reference Chon-Torres2017). Some of these issues were brought up during the symposium. Ciardullo, for example, talked about whether ecosystems should only be used in service of the human species, or whether they deserve their own agency. Ciardullo highlighted that our current building industry is focused on controlling the environment which is in stark contrast to the multitudes of interactions resulting from various organisms within ecosystems. Hence, are we ready to let go of control over other life and what would that look like? The reasons to incorporate nonhuman life into space exploration can vary from the need to develop closed-loop systems to biophilia, and it is critical to be diligent in measuring and communicating these reasons alongside designing solutions for space habitats.

Planetary protection was another topic that was discussed. Considerable effort has been dedicated to addressing planetary protection concerns within the inner Solar System exploration endeavors. Specifically, for missions targeting Mars, comprehensive internationally recognized guidelines have been established (Rettberg et al. Reference Rettberg, Antunes, Brucato, Cabezas, Collins, Haddaji, Kminek, Leuko, McKenna-Lawlor, Moissl-Eichinger, Fellous, Olsson-Francis, Pearce, Rabbow, Royle, Saunders, Sephton, Spry, Walter and Treuet2019). In order to avoid interplanetary contamination, all biological materials used for space applications would need to comply with planetary protection requirements for robotic or human missions and also with the current Committee on Space Research human mission principles and guidelines (Kminek and Conley Reference Kminek and Conley2017). In some cases (e.g. the Moon), requirements ask only for a short planetary protection plan to outline intended or potential impact targets. In other cases (e.g. Mars), detailed documentation is required including a probability of contamination analysis, a bioassay to enumerate the bioburden, and an inventory of the bulk constituent organics etc. (Kminek and Conley Reference Kminek and Conley2017). On the other hand, the issue of safety and contamination also works in reverse (backward and forward contamination). We also need to make sure that Earth is not getting contaminated by potential lifeforms from space.