Review of Failure Modes of a Photobioreactor System Used for Long Duration Spaceflight Environmental Control and Life Support
Aerospace Engineering and Sciences
University of Colorado, Boulder, CO, 80309
NASA is currently planning human spaceflight missions with longer duration than ever before.
Crewed missions mean environmental control and life support systems (ECLSS) must be incorporated into mission designs to meet crew metabolic requirements. Today, ECLSS technology is partly open-loop, still using some consumables and producing waste. This approach can quickly become mass or volume prohibitive, as the system scales with mission size.
Closed-loop technologies, specifically photosynthetic algal photobioreactors, can offer multiple functions such as air revitalization (CO2 absorption and O2 provision) and thermal control with less launch mass and volume for long-duration flights.
As a result of this review, photobioreactor designs can continue to strive for greater reliability and robustness by being cognizant of potential failure modes, with inclusion of mitigation methods or failure tolerance.
While the failures associated with application are relatively untested in the flight environment, terrestrial experiments have established hypotheses about flight effects to algal cultures. In terrestrial settings, it has been shown that algal cultures can address the functions of an ECLS system, but this needs to be tested in the operational environment (e.g. spaceflight and surface habitats) as well.
Biological systems are adaptable to their environment, but unfortunately this might leave the system operating outside of its required threshold. System response needs to be characterized for the expected operational environments, and additional resource (e.g. CO2 and micro-nutrients) requirements will flow from its result. The modes, causes, and effects presented here are conclusive with current physiology and space system knowledge.