Hierarchical Control of Space Closed Ecosystems: Expanding Microgrid Concepts to Bioastronautics

Abstract

One of the main challenges of human space exploration is the development of artificial ecosystems, which can be used as life support systems (LSSs) to enable long-duration human space missions. In an open LSS, no food generation or waste treatment is provided in space, and supplies from Earth are necessary. According to Figure 1, considering the approximate metabolic consumables and hygiene water as well as the number of crewmembers [1], a huge mass would be required to be transported from Earth, which brings the necessity of a regenerative or closed LSS [2]-[4]. Closed ecological systems (CESs) are ecosystems without any matter exchange with the outside environment [2]. The most advanced humanmade CESs include Advanced Life Support System Test Bed (ALSSTB) (the NASA Johnson Space Research Center, Houston, Texas), Biosphere 2 (Oracle, Arizona), BIOS-3 (Krasnoyarsk, Russia-no longer operative), the Closed Ecology Experiment Facility (CEEF) complex (Rokkasho, Japan), the Micro-Ecological Life Support System Alternative (MELiSSA) Pilot Plant (MPP) (Universitat Aut?noma de Barcelona, Spain), and the Concordia Antarctica Station, which are different from one another with respect to their complexity, size, and degree of closure [2]. CESs are necessary for long-term manned space missions, which aim to minimize support from Earth. They are composed of several specific compartments that, together, reproduce the main functionalities of an ecological system in a continuous mode of operation and under controlled conditions.