In assessing Mustronaut’s impact, we recognize the importance of two-way communication with stakeholders. Relying solely on internal team assumptions is insufficient for project optimization. Therefore, a structured tool is necessary to effectively integrate stakeholder feedback and translate these insights into design improvements in a timely manner.
In advancing the project, we followed a reflection framework and carried out the following practices:
- Anticipate Before each interaction, we clearly define the communication objectives. This “question-driven” approach ensures that every interview or discussion provides key insights for the project.
- Reflect Through exchanges with experts and the public, we continuously reflect on the project direction. These reflections guide the iterative development of strains, allowing us to integrate new functional modules.
- Engage We maintain two-way communication with stakeholders. This multi-level engagement helps advance the project toward practical applications.
- Act Based on feedback, we implement concrete actions.
Through this Anticipate–Reflect–Engage–Act (AREA) cycle, Mustronaut has continuously evolved in human practices, progressing from a first-generation HMB-only strain to a comprehensive solution with muscle protection, emotional regulation, and safety features.
Human Practice
Our journey began with the “space dream” in the minds of our team members. While following the return of Shenzhou-18 astronauts, we noticed that astronauts often required assistance to exit the capsule, prompting the question: why does this happen? Through discussions with aerospace experts, we learned that it is closely related to muscle atrophy commonly experienced in microgravity environments. Further research and interviews highlighted challenges such as weightlessness, insufficient nutrition, and high equipment costs, all critical issues for space health. This inspired us to consider: if ordinary people can access space in the future, how can we safeguard their health?
Based on this, we interviewed fitness trainers and nutritionists and learned that HMB is a common anti-sarcopenia supplement, but astronauts’ diets cannot meet the required levels. Advice from synthetic biologists helped us optimize metabolic pathways, leading to the introduction of yciA thioesterase to enhance HMB production. Subsequently, discussions with space professionals and psychologists revealed that the enclosed space environment can cause emotional issues, prompting us to add a serotonin synthesis module for dual support of muscles and mood. At the same time, feedback from bioengineering researchers and literature review motivated the development of in vivo suicide systems and extracorporeal safety measures, ensuring biosafety for the project.
To promote the practical application of Mustronaut, we visited probiotic powder manufacturers to learn about freeze-drying processes, consulted regulatory agencies and lawyers on market approval and intellectual property protection, and discussed commercialization possibilities with investors. These efforts allowed us to envision a clear path for Mustronaut to evolve from a laboratory concept into a health-protective product for future space travelers.
Our human practices journey can be summarized in four stages:
- Problem Identification — Observing astronauts’ post-mission muscle weakness and raising the space health issue.
- Solution Construction — Iteratively developing the HMB + serotonin engineered probiotic through expert guidance and experiments.
- Project Safety — Designing an arabinose-inducible in vivo suicide system and incorporating space waste incineration measures to ensure biosafety.
- Commercial Exploration — Visiting manufacturers, regulatory authorities, lawyers, and investors to lay the foundation for Mustronaut’s market entry.
Problem Identification
Aerospace Experts
While following the return of Shenzhou-18 astronauts, we noticed that astronauts often needed to be assisted out of the capsule, which sparked the team’s curiosity: why does this happen?
Before conducting interviews, we set communication objectives:
- Understand the specific effects of microgravity on the human body.
- Explore the direct causes of astronauts' muscle weakness.
- Clarify the current methods used in space missions to address this issue.
By approaching discussions with predefined questions, we aimed to validate our initial assumptions about space health risks and identify entry points for subsequent project design.
Through discussions with aerospace experts, we learned that astronauts, after prolonged exposure to microgravity, experience atrophy of antigravity muscles due to lack of effective stimulation. This is a major reason why astronauts cannot stand independently upon return. Experts also noted that current solutions mainly rely on large-scale exercise equipment and long-duration training, which are time-consuming, labor-intensive, and costly, and cannot fundamentally solve the problem.
During reflection, we realized:
- Muscle atrophy is an inevitable health challenge in space travel.
- Existing interventions are incomplete, with high costs and low compliance.
- If ordinary passengers travel to space in the future, this risk will become more common.
In discussions with experts about potential project directions, we proposed: could nutritional supplements or biotechnological interventions partially replace traditional exercise-based approaches? Experts affirmed this idea and highlighted that finding convenient and low-cost supportive solutions is an important future research direction.
Based on the insights from this interview, we took the following actions:
- Established muscle health as the core entry point for the Mustronaut project.
- Conducted literature review to explore existing supplements and metabolic pathways.
- Set “addressing muscle atrophy” as the primary goal for the first-generation strain, laying the foundation for project iteration.
Space Medicine Experts
After initially confirming the problem of astronauts’ post-mission muscle weakness due to microgravity, we aimed to further understand:
- What are the specific physiological effects of microgravity on the human body?
- What is the mechanism of muscle atrophy?
- What mitigation strategies are currently used in space missions?
With these questions in mind, we decided to interview space medicine experts to validate our hypotheses.
Currently, responses to muscle atrophy in space almost entirely rely on exercise interventions, such as resistance training and treadmill workouts. Experts emphasized that exercise is the only validated method to mitigate muscle loss, but it suffers from being time-consuming, equipment-heavy, and limited in effectiveness.
In reflection, we recognized that:
- Existing methods have clear limitations.
- The damaging effects of the space environment on the body are more complex than initially imagined.
- There is a need to develop new, more lightweight supportive solutions in the future.
During discussions, we explored potential alternative or supplementary approaches:
- We proposed whether nutritional supplements or biometabolic products could assist in protecting muscle health.
- Experts noted that future directions may include nutritional interventions and metabolic regulation, but currently, no mature solutions exist.
Based on expert feedback, we took the following actions:
- Treated “exercise + nutritional supplements” as complementary rather than mutually exclusive.
- Maintained exploration space for future auxiliary solutions.
Space Equipment Experts
After confirming the health risks in space, we realized another key issue: existing exercise and life-support equipment are bulky and expensive. Given that rocket launch costs are calculated by weight, this poses a significant barrier to future space travel for ordinary passengers.
Before conducting interviews, we set the following objectives:
- Understand the transport costs and resource consumption of aerospace equipment.
- Clarify why space travel remains so expensive.
- Explore whether more lightweight health support solutions could be feasible.
Experts informed us that the volume and weight of equipment are key factors in aerospace costs. Launch costs per kilogram can reach tens of thousands of US dollars, meaning that carrying exercise equipment or large-scale nutritional supplies would consume valuable payload space.
Through reflection, we realized:
- Mustronaut’s design must emphasize lightweight and cost-efficiency.
- If engineered probiotics can synthesize necessary health molecules in vivo, it would save precious transport resources.
- This approach could address astronaut health issues and reduce cost barriers for future commercial space travel.
During discussions, we proposed the concept: instead of relying on bulky equipment, could probiotics act as “in-body factories” to produce required molecules, partially replacing traditional equipment?
Experts confirmed the idea, emphasizing that as long as safety and stability are ensured, such a solution holds great potential for future space missions, as it directly addresses the core need for weight reduction and cost savings.
Based on these insights, we took the following actions:
- Established “lightweight design” as a core advantage of Mustronaut.
- In subsequent commercial discussions, highlighted launch cost savings to attract aerospace companies and investors.
Questionnaire Survey
During expert interviews, we gradually realized that future space travelers will not be limited to professional astronauts; ordinary people may also become passengers.
Therefore, before designing the questionnaire, we set the following objectives:
- Understand the public's awareness and interest in future space travel.
- Collect their concerns about costs, health risks, and microgravity environments.
- Confirm whether Mustronaut, as a health solution for future space passengers, is perceived as attractive.
From the questionnaire results, we learned that:
- Most people are excited about space travel, but generally perceive ticket prices as prohibitively expensive.
- A significant portion of respondents are concerned about health risks in microgravity, particularly muscle atrophy and physical adaptation.
- Many believe that high ticket costs are largely due to large, heavy life-support equipment, which aligns closely with conclusions from space equipment experts.
Upon reflection, we realized that the public's concerns resonate with expert opinions, indicating that Mustronaut's value lies not only in health protection, but also in reducing equipment reliance and alleviating cost pressures.
Based on the questionnaire and public feedback, we took the following actions:
- Clearly defined “future space passengers” as the target audience, not just professional astronauts.
- Positioned accessibility for ordinary consumers as a long-term vision in the commercialization pathway, leaving room for future market expansion.
Initial Product Determination
Nutritionists
After learning that astronauts commonly face muscle atrophy, we encountered a new question: can nutritional supplementation effectively prevent or mitigate muscle loss?
Therefore, before interviewing nutritionists, we set several objectives:
- Understand the daily diet and nutritional composition of astronauts during space missions.
- Explore whether nutrient intake can counteract muscle loss in microgravity.
- Identify if there are specific nutrients suitable for supplementation in space environments.
The nutritionists informed us that although astronauts’ diets are carefully planned, nutritional supply is limited, particularly in protein and essential amino acids, which cannot effectively counteract muscle loss caused by microgravity. Existing foods mainly meet energy needs and basic maintenance, but cannot fully support long-term health.
This led us to reflect that:
- Dietary supplementation alone is insufficient to address muscle atrophy due to microgravity;
- Limited space resources make it infeasible to carry large amounts of additional supplements or food;
- Our project could provide greater value by offering continuous in vivo nutritional support.
During discussions, we explored whether astronauts had tried special functional nutritional interventions. Nutritionists noted that some supplements have been attempted in space missions, but due to storage limitations, transport costs, and efficacy, the results were not ideal.
Based on this interview, we took the following actions:
- Focus future literature research on molecules that can be synthesized or continuously released in vivo;
- Establish “supplementing dietary insufficiencies” as one of the core starting points for Mustronaut’s design.
Fitness Coaches
After learning that astronauts’ diets are insufficient to effectively prevent muscle loss, we sought to explore:
- Which nutritional supplements are commonly used on Earth to maintain or enhance muscle health?
- Are there nutritional molecules suitable for adaptation into a space health support solution?
Therefore, we decided to interview fitness coaches to gather their experience in daily training and muscle maintenance.
The fitness coaches informed us that HMB (β-hydroxy-β-methylbutyrate) is a commonly used supplement among fitness enthusiasts. It can effectively reduce exercise-induced muscle breakdown and support muscle recovery and growth.
This led us to reflect that:
- If HMB is widely applied on Earth to mitigate muscle damage and atrophy, it may also be effective in microgravity environments to counteract muscle atrophy in space.
Fitness coaches informed us that HMB is a commonly used supplement among fitness enthusiasts. It can effectively reduce exercise-induced muscle breakdown and support muscle recovery and growth.
This led us to reflect that:
- If HMB is widely used on Earth to mitigate muscle damage and atrophy, it may also be applicable in space environments to counteract muscle loss in astronauts.
Inspired by this interview, we took the following actions:
- Established HMB as the first core product of the Mustronaut project;
- Began designing a de novo HMB biosynthesis pathway;
- Defined the core concept: producing HMB to help future space travelers mitigate muscle atrophy.
Metabolic Pathway Design
HMB Biosynthesis
Through expert consultations and literature research, we identified HMB as a key candidate molecule for mitigating muscle atrophy.
Before constructing the strain, our goals were:
- Identify a de novo HMB biosynthesis pathway that can function inside a probiotic chassis;
- Confirm the key enzymes and their functional roles;
- Introduce the pathway into a safe chassis strain, E. coli Nissle 1917, laying the foundation for the Mustronaut prototype.
Through literature review and comparison with existing studies, we identified that the HMB biosynthesis pathway primarily relies on four key enzymes: AtoB, MvaS, AibAB, LiuC.
This led us to reflect that:
- The pathway is relatively straightforward, requiring only a few key enzymes for efficient conversion, making it feasible in probiotics;
- Compared with chemical synthesis, microbial biosynthesis is greener and more sustainable;
- However, this version remains at the theoretical stage, and yield and stability may be limited, necessitating further optimization.
During the design process, we:
- Referenced previous research to ensure the rationale for enzyme selection and order;
- Discussed internally whether E. coli Nissle 1917 is suitable as the chassis;
- Combined this with stakeholder feedback to ensure alignment with the goal of providing lightweight nutritional support for space travelers.
Actions taken:
- Introduced the four key enzyme genes into E. coli Nissle 1917 via genetic engineering, constructing the first-generation engineered strain;
- Established this as the core starting point for Mustronaut and laid the foundation for subsequent optimization.
Yield Improvement
After completing the first-generation strain design, we realized that although the engineered strain could produce HMB, the yield might be insufficient to meet the long-term health needs of space travelers.
Therefore, when moving into the second-generation strain design, we set the following goals:
- Identify potential bottleneck steps, particularly in the conversion from HMB-CoA to free HMB;
- Explore whether the introduction of additional enzymes could improve the final product synthesis efficiency.
During discussions with synthetic biologists, we learned that thioesterases can facilitate the deacylation of HMB-CoA, efficiently releasing free HMB.
This insight led us to reflect that:
- Although the first-generation strain established the HMB synthesis pathway, there existed an efficiency bottleneck at the key step;
- Introducing an appropriate thioesterase could overcome this limitation;
- Selecting the right candidate enzyme was critical for improving yield and became a breakthrough point for the second-generation strain design.
Based on expert advice, we reviewed the literature and screened multiple enzymes for their characteristics.
After internal discussion and comparison, we ultimately chose yciA thioesterase, which has demonstrated effective catalytic performance in previous studies.
Actions Taken:
- Introduced the yciA thioesterase gene into the engineered strain, constructing the second-generation HMB-producing strain.
Serotonin Synthesis
After completing the first two generations of the HMB-producing strains, our core goal was to address muscle atrophy. However, when presenting the project to aerospace professionals, they raised a new concern: the confined and stressful environment in space could lead to low mood among travelers, potentially affecting the efficacy of HMB.
Thus, we set new exploration objectives:
- Understand the severity of space-related psychological health issues;
- Determine whether low mood affects metabolism and health support;
- Identify suitable molecular interventions for mood regulation.
Through interviews with psychologists, we learned that:
- Confined and microgravity environments can exacerbate negative emotions, sometimes leading to anxiety and depression;
- Long-term psychological stress not only affects mental state but can also interfere with physical recovery and therapeutic effects;
- Serotonin (5-HT) is a key neurotransmitter that can effectively alleviate low mood, improve sleep quality, and support cognitive function.
- Through reflection, we realized that addressing muscle atrophy alone is insufficient. To serve future space travelers, Mustronaut must integrate both physiological and psychological health support.
Integration of Serotonin Synthesis Module
During discussions, psychologists emphasized the role of serotonin in mood regulation and highlighted that existing studies have shown a close relationship between the gut microbiota and serotonin synthesis.
This further confirmed that:
- Incorporating a serotonin synthesis module into the engineered strain is both scientifically sound and highly aligned with the project objectives;
Based on this feedback and reflection, we took the following actions:
- Introduced the serotonin synthesis module in the third-generation strain;
- Enabled the engineered strain to secrete serotonin while producing HMB, achieving a dual function of muscle protection and mood regulation;
- Redefined Mustronaut’s positioning: no longer solely a solution for muscle atrophy, but a comprehensive platform for holistic health support for future space travelers.
Safety
At the early stage of project design, we recognized that biosafety must be the top priority, especially when participating in the iGEM competition. Although our project currently remains at the laboratory stage and cannot be directly applied, we still need to anticipate potential biosafety issues in the future.
Therefore, we set the following goals:
- Ensure the safe use of Mustronaut in the human body;
- Assess whether the engineered strain might leak or spread in the unique conditions of space;
- Establish a verifiable and interpretable safety protection system to support the smooth advancement of the project and its future translation into practical use.
Through discussions with bioengineering researchers, we learned that:
- The engineered strain must have an intracellular controllable suicide system, allowing immediate termination of its functions when needed to avoid potential risks;
- Environmental safety must also be considered, including waste management and potential leakage.
Through reflection, we recognized that:
- A comprehensive safety framework must address both in vivo and ex vivo dimensions;
- Biosafety is not only an iGEM compliance requirement, but also a key factor for the project's social acceptance and potential real-world application.
In vivo safety: Based on researchers’ recommendations, we implemented an arabinose-inducible suicide system, which triggers the MazF toxin to rapidly eliminate the engineered strain when needed.
Ex vivo safety: Literature and references indicate that spacecraft waste is strictly collected and incinerated at high temperatures upon return to Earth, minimizing any environmental risk.
We also interviewed space operation personnel, who confirmed the waste management and containment procedures aboard spacecraft. This further validated that the engineered strain will not enter the external environment, ensuring biosafety for future applications.
Based on these insights, we took the following measures:
- Incorporated the in vivo suicide system as a core safety module in the Mustronaut design;
- Although Mustronaut remains at the laboratory stage, we are proactively designing a comprehensive biosafety plan for potential future applications, ensuring scientific, societal, and ethical feasibility.
Commercialization
Product Translation
In the design of Mustronaut, we must consider not only whether the strain produces the target molecules effectively, but also how to convert the engineered strain into a usable product.
We set the following objectives:
- Understand the industrial production processes of probiotic formulations;
- Explore scalable production and portable packaging suitable for space environments;
- Lay the foundation for future commercial deployment.
From literature and industry research, we realized that:
- Freeze-drying is the main method for probiotic preparation, but different processes affect strain viability differently;
- Space applications require high stability and lightweight packaging to minimize launch costs;
- To truly serve astronauts or space tourists, Mustronaut must support long-term storage, convenient transport, and safe use.
We interviewed professional probiotic production factories, learning that they possess complete experience across the production-to-market chain, including strain cultivation, freeze-drying, excipient addition, encapsulation, and product distribution.
Their feedback confirmed that:
- It is feasible to develop a scalable production system suitable for long-term space missions and space tourism based on existing processes;
- In terms of packaging, single-dose freeze-dried capsules or liquid-encapsulated granules could enhance portability and user experience.
Based on these insights, we took the following measures:
- Adopted freeze-dried powder as Mustronaut’s main formulation and planned various portable packaging options;
- Integrated scalable production and supply chain design into the project implementation and commercialization roadmap.
Aerospace-Biology Crossfield Expert Consultation
In advancing the Mustronaut project, we must consider not only muscle atrophy and mood regulation but also the effects of the space environment on the engineered strain.
Our objectives were to:
- Understand whether space radiation could affect strain stability and safety;
- Explore storage and consumption methods suitable for space conditions;
- Design packaging that is both portable and protective, maximizing strain viability.
After discussions with aerospace-biology crossfield experts, we realized:
- Space radiation could induce strain mutations, posing both safety and functional risks;
- In a microgravity environment, conventional capsules or powder formulations are inconvenient to consume;
- Therefore, the product design must simultaneously meet biosafety, ease of use, and radiation protection requirements.
Experts emphasized the importance of radiation risk and suggested optimizing formulation and packaging. Based on probiotic factory experience, we explored multiple formulation strategies and eventually proposed the liquid-encapsulated probiotic powder spheres concept:
- Powdered probiotics are encapsulated into small spheres using a thin-film membrane;
- The liquid coating facilitates swallowing and provides an additional protective layer, mitigating radiation effects on the strain.
Based on these insights, we took the following actions:
- Finalized Mustronaut’s formulation as individually packaged probiotic powder-liquid units, balancing portability and user experience;
- Documented the liquid-encapsulated powder sphere design in the Wiki and commercialization roadmap as a dual solution for radiation protection and convenient consumption.
Product Market Entry
As Mustronaut’s design gradually matured, we realized that regulatory compliance and legal protection would be critical for translating it from the laboratory to the market.
Therefore, we set the following objectives:
- Understand the approval processes for engineered probiotic products entering the market;
- Explore how to secure intellectual property protection for Mustronaut’s core innovations (HMB + serotonin synthesis) from the early stages of R&D;
- Establish a compliance and legal pathway to support future commercialization.
During our research, we discovered:
- As a specialized engineered probiotic product, approval processes are relatively strict, involving both drug regulatory and biosafety reviews;
- Without early intellectual property protection, innovative achievements may face imitation or infringement risks in future applications;
- Mustronaut's innovation is not only scientific but also requires legal measures to safeguard its market competitiveness.
Regulatory Authorities: We interviewed relevant regulators and learned about the market entry process for similar products, including clinical validation, approval procedures, and market access requirements.
Legal Experts: We consulted lawyers to understand how to protect Mustronaut’s technology and brand via patents and trademarks, reducing potential intellectual property disputes.
Based on this feedback, we took the following actions:
- Integrated regulatory approval pathways into our commercialization and patent strategy, clarifying the steps required for future market entry;
- Initiated discussions on patent and trademark protection for Mustronaut, seeking legal safeguards for key metabolic modules, packaging formats, and brand naming.
Commercial Potential Assessment of Mustronaut
As the project gradually matured and took shape, we realized that translating scientific achievements into practical applications requires capital support and recognition.
Objectives:
- Engage with investors to validate Mustronaut's commercial value and future market potential;
- Understand their concerns regarding product deployment and business model;
- Explore potential funding pathways to provide external resources for product development.
Through internal discussions and market research, we recognized that:
- Mustronaut’s positioning goes beyond scientific innovation, addressing the emerging demand for health support for space travelers;
- Investors primarily focus on market size, technical barriers, and commercial prospects;
- Therefore, it is crucial to translate our scientific achievements into a clear commercial narrative to gain investor approval.
During discussions with investors, we presented Mustronaut’s product design and future roadmap, including:
- The scientific principles and innovative features of the engineered bacterial strain;
- The potential target market (professional astronauts and space tourists);
- The pathway for future scale-up production and packaging implementation.
Investors showed interest and provided positive feedback and support.
Actions Taken:
- We integrated investor feedback into the commercialization plan, optimizing the product deployment strategy and market positioning. Currently, Mustronaut's market strategy focuses first on B2B aerospace enterprises, with gradual expansion to general consumers;
- Laid the foundation for future fundraising, giving the project both scientific innovation and commercial development momentum.
