John Hogan

Towards synthetic biological approaches to resource utilization on space missions.

This paper demonstrates the significant utility of deploying non-traditional biological techniques to harness available volatiles and waste resources on manned missions to explore the Moon and Mars. Compared with anticipated non-biological approaches, it is determined that for 916 day Martian missions: 205 days of high-quality methane and oxygen Mars bioproduction with Methanobacterium thermoautotrophicum can reduce the mass of a Martian fuel-manufacture plant by 56%; 496 days of biomass generation with Arthrospira platensis and Arthrospira maxima on Mars can decrease the shipped wet-food mixed-menu mass for a Mars stay and a one-way voyage by 38%; 202 days of Mars polyhydroxybutyrate synthesis with Cupriavidus necator can lower the shipped mass to three-dimensional print a 120 m3 six-person habitat by 85% and a few days of acetaminophen production with engineered Synechocystis sp. PCC 6803 can completely replenish expired or irradiated stocks of the pharmaceutical, thereby providing independence from unmanned resupply spacecraft that take up to 210 days to arrive. Analogous outcomes are included for lunar missions. Because of the benign assumptions involved, the results provide a glimpse of the intriguing potential of ‘space synthetic biology’, and help focus related efforts for immediate, near-term impact.

Grand challenges in space synthetic biology

Space synthetic biology is a branch of biotechnology dedicated to engineering biological systems for space exploration, industry and science. There is significant public and private interest in designing robust and reliable organisms that can assist on long-duration astronaut missions. Recent work has also demonstrated that such synthetic biology is a feasible payload minimization and life support approach as well. This article identifies the challenges and opportunities that lie ahead in the field of space synthetic biology, while highlighting relevant progress. It also outlines anticipated broader benefits from this field, because space engineering advances will drive technological innovation on Earth.

Functional and taxonomic dynamics of an electricity-consuming methane-producing microbial community.

The functional and taxonomic microbial dynamics of duplicate electricity-consuming methanogenic communities were observed over a 6 months period to characterize the reproducibility, stability and recovery of electromethanogenic consortia. The highest rate of methanogenesis was 0.72 mg-CH4/L/day, which occurred during the third month of enrichment when multiple methanogenic phylotypes and associated Desulfovibrionaceae phylotypes were present in the electrode-associated microbial community. Results also suggest that electromethanogenic microbial communities are very sensitive to electron donor-limiting open-circuit conditions. A 45 min exposure to open-circuit conditions induced an 87% drop in volumetric methane production rates. Methanogenic performance recovered after 4 months to a maximum value of 0.30 mg-CH4/L/day under set potential operation (-700 mV vs Ag/AgCl); however, current consumption and biomass production was variable over time. Long-term functional and taxonomic analyses from experimental replicates provide new knowledge toward understanding how to enrich electromethanogenic communities and operate bioelectrochemical systems for stable and reproducible performance.

Development Status of a Low-Power CO2 Removal and Compression System for Closed-Loop Air Revitalization

The ‘low-power CO2 removal (LPCOR) system’ is an advanced air revitalization system that is under development at NASA Ames Research Center. The LPCOR utilizes the fundamental design features of the ‘four bed molecular sieve’ (4BMS) CO2 removal technology of the International Space Station (ISS). It will reduce the cabin air CO2 concentration by 60% with a 50% power savings compared to the current ISS standard. In addition, it will recover pure, compressed CO2 for oxygen recovery. LPCOR improves the power efficiency by replacing the desiccant beds of the 4BMS with a membrane dryer and a state-of the art structured adsorbent device that require 25% of the thermal energy required by the 4BMS desiccant beds. The CO2 removal and recovery functions are performed in a two-stage adsorption compressor. CO2 is removed from the cabin air and partially compressed in the first stage. The second stage performs further compression and delivers the compressed CO2 to a reduction unit such as a Sabatier reactor for oxygen recovery. This paper describes the development status of the LPCOR system, including the breadboard experiments to determine the performance parameters of the full-scale LPCOR components for an optimized process, characterization tests and long-term performance testing of individual components. Also discussed in this paper are the flow distribution challenges encountered in a low pressure-drop system such as the residual water adsorber, configured as an engineered structured sorbent, and the efforts to mitigate the flow-related issues.

Potential Applications for Bioelectrochemical Systems for Space Exploration

The goals of future long-duration space exploration require higher degrees of material closure and self-sustainability. Bioelectrochemical systems (BESs) have the potential to expand the utilization of biological processes for the in situ generation of products and the advancement of life support systems. BESs employ unique microorganisms that utilize extracellular electron transport to increase metabolic capacity and efficiency. Waste streams and planetary resources could be utilized for the production of a wide array of electrobiocommodities by exploiting and potentially enhancing naturally occurring reactions in microbial systems. BESs have the potential to yield a wide array of space-relevant products, such as biofuels, bioplastics, bioadhesives, therapeutics and food products. This paper discusses the application of BESs in space, including potential products, reactor design, and the unique challenges associated with BES operation in space environments.