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Electrolytic oxygen generation system (EOGS) is the only system that can provide oxygen for astronauts in a physicochemical regenerative way in a long-term manned spacecraft. In order to ensure that the astronauts in the cabin can obtain a continuous and enough oxygen supply, it is necessary to carry out real-time condition monitoring and fault diagnosis of the EOGS. This paper deals with condition monitoring and fault diagnosis of the EOGS. Firstly, the dynamic model of the system is established based on the principle electrolysis for actual oxygen production system and the state observer of the system has been designed by using unscented Kalman filter (UKF). The total pressure in the cabin and the partial pressure of oxygen in the electrolytic cell can be observed. Then, considered the actual conditions of the manned space mission with one more astronaut, i.e., 3 astronauts, the simulation experiment is carried out. The simulation results show that the method can effectively estimate the system state, and it is of great significance to ensure the normal operation of the electrolytic EOGS system in the space station. [ABSTRACT FROM AUTHOR]

Electrolytic oxygen generation system (EOGS) is the only system that can provide oxygen for astronauts in a physicochemical regenerative way in a long-term manned spacecraft. In order to ensure that the astronauts in the cabin can obtain a continuous and enough oxygen supply, it is necessary to carry out real-time condition monitoring and fault diagnosis of the EOGS. This paper deals with condition monitoring and fault diagnosis of the EOGS. Firstly, the dynamic model of the system is established based on the principle electrolysis for actual oxygen production system and the state observer of the system has been designed by using unscented Kalman filter (UKF). The total pressure in the cabin and the partial pressure of oxygen in the electrolytic cell can be observed. Then, considered the actual conditions of the manned space mission with one more astronaut, i.e., 3 astronauts, the simulation experiment is carried out. The simulation results show that the method can effectively estimate the system state, and it is of great significance to ensure the normal operation of the electrolytic EOGS system in the space station.

Abstract Water management subsystem (WMS) is a major component of the controlled ecological life support system (CELSS). For guaranteeing the water requirement of crop growth and crewmember's daily life, a WMS was established in a 4 person 180-day integrated experiment (carried out in Shenzhen, China, 2016) to maintain a closed cycle with a total water amount of ~23 m3. The design and operation of the WMS was summarized as follows: (1) Collection and allocation of condensate water. About 917 L/d condensate water (>98% was from plants' evapotranspiration) was collected, and ~866 L/d of which was reused as plant nutrient solution after ultraviolet (UV) disinfection, and 50.6 L/d was used as the raw water for the domestic water supply module (DWS). (2) Domestic water supply. The condensate water from the plant cabin was purified through the DWS, a modified membrane bioreactor (MBR) system, and then provided hygiene and potable water to 4 crewmembers with different water quality standards. (3) Wastewater recovery. 51.4 L/d wastewater from urination and personal hygiene were treated together via a biological wastewater treatment process to complete the conversion of nitrogen and organic matters, and then recycled to plant nutrient solution. (4) Nutrient solution recycling. In the overall water cycle process, the plant nutrient solution was continuously self-circulated and the water quality of which was maintained at a relatively stable level with total organic carbon of 20–30 mg/L and NH 4 +-N < 1.0 mg/L. The 180-day continuous operation demonstrated that a 100% water closure was achieved. Based on the results of this study, an upgraded water cycle system for larger-scale and longer-term CELSS has been proposed. Graphical abstract Unlabelled Image Highlights • A 100% water closure was obtained in CELSS during the whole time of 4-person-180-day integrated experiment. • The water quantitative model of water cycle was established. • The safety of water quality was guaranteed by domestic water supply module and wastewater treatment module. • An upgraded water cycle system for the larger-scale and longer-term CELSS was proposed. [ABSTRACT FROM AUTHOR]

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This paper presents the conceptual design and analysis of a system intended to increase the range, scientific capability, and safety of manned lunar surface exploration, requiring only a modest increase in capability over the Apollo mission designs. The system is intended to enable two astronauts, exploring with an unpressurized rover, to remove their space suits for an 8-h rest away from the lunar base and then conduct a second day of surface exploration before returning to base. This system is composed of an Environmental Control and Life Support System on the rover, an inflatable habitat, a solar shield and a solar power array. The proposed system doubles the distance reachable from the lunar base, thus increasing the area available for science and exploration by a factor of four. In addition to increasing mission capability, the proposed system also increases fault tolerance with an emergency inflatable structure and additional consumables to mitigate a wide range of suit or rover failures. The mass, volume, and power analyses of each subsystem are integrated to generate a total system mass of 124 kg and a volume of 594 L, both of which can be accommodated on the Apollo Lunar Roving Vehicle with minor improvements. [ABSTRACT FROM AUTHOR]

This article presents a state evaluation model to assess the state of health of a manned spacecraft’s environmental control and life support system, which ensures the safety of astronauts and guarantees space mission success. A state evaluation based on integrated system health management is introduced into the manned spacecraft’s environmental control and life support system to deal with safety and maintenance requirements. Due to the uncertainty and the complexity of the system, there is little research concerning state evaluation for manned spacecraft’s environmental control and life support system that considers fuzziness at the system level. A numerical example illustrates the proposed fuzzy comprehensive state evaluation model that, from a holistic perspective, takes all criteria into account, combines objective tests with subjective judgments and incorporates fuzziness and uncertainty into the ranking of the manned spacecraft’s environmental control and life support system health level. The proposed model is demonstrated by solving a state evaluation problem and the comparison analysis. It also reveals the state impact factors for manned spacecraft’s environmental control and life support system health management and conducts a valuable health state evaluation framework for complex systems. [ABSTRACT FROM AUTHOR]

The feasibility and design of the CultCube 12U CubeSat hosting a small Environmental Control and Life Support Systems (ECLSS) for the autonomous cultivation of a small plant in orbit is described. The satellite is aimed at running experiments in fruit plants growing for applications in crewed vehicles for long-term missions in space. CultCube is mainly composed of a pressurized vessel, constituting the outer shell of the ECLSS, and by various environmental controls (water, nutrients, air composition and pressure, light, etc.) aimed at maintaining a survivable habitat for the fruit plants to grow. The plant health status and growth performances is monitored using hyperspectral cameras installed within the vessel, able to sense leaves' chlorophyll content and temperature, and allowing the estimation of plant volume in all its life cycle phases. The paper study case is addressed to the in-orbit experimental cultivation of a dwarf tomato plant (MicroTom), which was modified for enhancing the anti-oxidants production and for growing in stressful environments. While simulated microgravity tests have been passed by the MicroTom plant, the organism behaviour in a real microgravity environment for a full seed-to-seed cycle needs to be tested. The CultCube 12U CubeSat mission presents no particular requirements on the kind of orbit, whereas its minimum significative duration corresponds to one seed-to-seed cycle for the plant, which is 90 days for the paper study case. In the paper, after an introduction on the importance of an autonomous testbed for plant cultivation, in the perspective of the implementation of bioregenerative systems on-board future manned long-term missions, the satellite design and the MicroTom engineered plant for in-orbit growth are described. In addition to the description of the whole set of subsystems, with focus on the payload and its controllers and instrumentation, the system budgets are presented. Finally, the first tests conducted by the authors are briefly reported., (Copyright © 2020 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.)