Developing Sustainable Life Support System Concepts

Abstract

Sustainable spacecraft life support concepts may allow the development of more reliable technologies for long duration space missions. Currently, life support technologies at different levels of development are not well evaluated against each other, and evaluation methods do not account for long term reliability and sustainability of the hardware. This paper presents point-of-departure sustainability evaluation criteria for life support systems, that may allow more robust technology development, testing and comparison. An example sustainable water recovery system concept is presented. L IntroductionSustainability is the capacity to endure. Long duration spaceflight, as anticipated for Moon and Mars missions, will require hardware that is less prone to failure and generally more rigorous and sustainable than the current stateof-the-art. Sustainable Environmental Control and Life Support Systems (SECLSS) may be developed to function for long periods of time in harsh environments, with limited maintenance and resupply. Water recovery, air revitalization, habitation, food and power systems may benefit from considering sustainability a design goal.The SECLSS project is designed to develop rough life support system architectures, evolve technology concepts, and collaborate with NASA partners to consider long term sustainability as a design driver for life support systems. One example application requiring innovation is wastewater management ; wherein wastewater fouling is accommodated by the design of the fluid mana gement hardware. This paper provides an overview of the SECLSS project concept and proposed sustainability evaluation criteria for ECLSS technologies, and details a preliminary example technology for water recovery on the lunar outpost. II. BackgroundA long-terns lunar outpost will require sustainable life support technologies that are capable of functioning for years with minimum resupply and maintenance. While life support resources such as grater and air will remain in short supply, the availability of gravity, energy, and natural resources on the lunar surface allow for innovation in the design of outpost technologies, potentially including the adoption of terrestrial technologies previously not feasible for short duration microgravity flight.As missions become extended in duration and move toward more self-reliant operations, new demands are placed on the life support system design. Thus far, all indications have suggested that the lunar outpost water recovery systems will be evolved from current spacecraft technologies, including urine pretreatment and distillation'. However, these technologies were developed for microgravity compatibility, and may carry undesirable fouling and failure mode heritage from this environment. For example, it is well recognized that water handling systems used in a spacecraft are prone to failure caused by biofouling and mineral scaling, which can clog mechanical systems and degrade the performance of capillary-based technologies. The recent challenges with the Urine Proc...