Influence of crop cultivation conditions on space greenhouse equivalent system mass

Abstract

Future crewed space missions will make use of hybrid life support systems to sustain human presence in space and on other planetary bodies. Plants fulfill essential roles in those systems such as carbon dioxide removal, oxygen production, and food production. The systems required to grow plants in space, so-called space greenhouses, are complex and need to be built as efficient as possible. Thereby, the resources mass, volume, energy, and crewtime required to grow a certain amount of food are essential because these parameters define the effectiveness of the space greenhouse. However, the required resources depend on the size of the greenhouse which in turn depends on the productivity of the crops which in turn depend on the cultivation conditions. The output of such a system can be calculated using the Modified Energy Cascade plant production model, which can simulate the food output depending on the cultivation conditions. Traditionally, life support systems are evaluated using the Equivalent System Mass method, which can determine the cost effective life support architecture for a given mission scenario. By combining both, the influence of the cultivation conditions inside the space greenhouse on the effectiveness of the complete system can be investigated. It seems counterintuitive first, but it is more effective to increase the energy per area provided to the plants in the form of light. Although that increases the electrical energy demand per area, the reduction in required cultivation area and, therefore, system size leads to a more efficient system.

Theoretical design of a space bioprocessing system to produce recombinant proteins

“…Given these differences are not large enough for system selection, this metric cannot be used to prioritize designs for implementation. The ESM estimates are comparable to a proposed monoclonal antibody production system at 300-1,700 kg eq 45 as well as a plant biomass system for food production at 300-1,300 kg eq per kg 10 . For theoretical designs such as the proposed biomanufacturing systems, a difference of less than 10-fold suggests similar infrastructure costs.…”

“…The bound protein is eluted from the resin using elution buffer (10), separated by the centrifuge, and collected in the product reservoir (11).…”

“…Not all enzymes retain activity in low temperature storage and in situ production of enzymes would mitigate risks of relying solely on low temperature storage of proteins with limited stability. Space biomanufacturing systems have the potential to produce enzymes and other biological materials using in situ resources during a Mars mission [8][9][10][11][12][13] . Space systems must minimize cost and crew time, while assuring astronaut safety and addressing effects of increased radiation and reduced gravity [14][15][16][17] .…”

Evaluating the cost of pharmaceutical purification for a long-duration space exploration medical foundry

“…To contextualize the ESM results of this analysis, we compare them to recently reported ESM outputs of a Mars surface greenhouse 67 . In this study, they report an ESM output of ~200 -1,200 kg per kg plant biomass, excluding consumable costs (i.e., plant growth substrate, nutrient salts, cleaning agents), which they term as logistics mass.…”

Evaluating the Cost of Pharmaceutical Purification for a Long-Duration Space Exploration Medical Foundry

“…ESM has been used to evaluate the mass of all of the resources of a larger system including water, shielding materials, agriculture and recycle loop closure. Currently, ESM remains the standard metric for evaluating advanced life support technology platforms ( Hogan et al, 2000 ; Zabel, 2020 ). In the Space Systems Bioengineering context of realizing a biomanufactory on the surface of Mars ( Berliner et al, 2020 ), recent advances in extending this metric have been proposed in the form of extended ESM which attempts to address complexities stemming from multiple transit and operations stages, as would be required to support a crewed mission to Mars ( Berliner et al, 2021 ).…”