The “C.E.B.A.S. MINI-MODULE”: A self-sustaining closed aquatic ecosystem for spaceflight experimentation

42nd International Conference on Environmental Systems

2012

On April 10th 2010, at the Kennedy Space Center, President Barack Obama pronounced his "Remarks on Space Exploration in the 21st Century." The President included closedloop life support systems (LSS) as a technology that "can help improve daily lives of people here on Earth, as well as testing and improving upon capabilities in space." A challenge to enable research on LSS is the need for educational capacities that may open up opportunities for teachers and students to teach, learn, and experiment with a small-scale version of these systems. Such is the case in higher-education institutions with programs in life sciences and engineering. These may have educational platforms available in their laboratories to, for example, study attributes of robustness or optimality in controllers driving servomechanisms and electric motors, but there is no small-scale platform available to study the ecophysiological performance of higher plants in an isolated artificial ecosystem. This paper presents aquatic habitats as educational platforms for experiments in closed-loop LSS, and the lessons learned while working with undergraduate students at the Human-Automation Systems Lab of the Georgia Institute of Technology. It presents the challenges that these systems pose to students in engineering and sciences, and highlights the opportunities to support higher-education-level teaching and learning of concepts in science, technology, engineering, and mathematics (STEM) fields.

Section: A Backgroundmentioning

confidence: 99%

Educational Value of Experiments on Life Support Systems with Ground-Based Aquatic Habitats

42nd International Conference on Environmental Systems

2012

“…Past experiences reported in the literature make use of aquatic habitats for experiments in zoology and physiology in low Earth orbit (LEO), [3][4][5][6][7] and for ecotoxicological studies in ground-based experiments. 2,8 The results obtained in LEO during Space Shuttle missions STS-89 and STS-90 show that microgravity does not affect aquatic habitats considerably for exposure periods of up to 16 days.…”

Section: A Backgroundmentioning

confidence: 99%

“…This experiment intends to reproduce results comparable to those reported with the CEBAS minimodule. 5 In this case, a simple controller turns on and off the lamp of the second compartment when the DO concentration in the fourth reaches 4.0 [mg/l] and 6.5 [mg/l], respectively. The simulation time is 21 days and its initial conditions are in equilibrium with the equivalent concentration of the atmosphere at 22 • C at sea level.…”

Section: B Simulations Performed On the Modelmentioning

confidence: 99%

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Modeling, Design and Simulation of a Reconfigurable Aquatic Habitat for Life Support Control Research

41st International Conference on Environmental Systems

2011

This paper presents the design, modeling, and simulation of a reconfigurable aquatic habitat for experiments in regenerative life support automation; it supports the use of aquatic habitats as a small-scale approach to automation experiments relevant to largerscale regenerative life support systems. The habitat consists of a ten-gallon tank with four compartments, containing animal and botanical elements. The water volume serves as the medium through which life-support compounds, like oxygen, are transferred between organisms. A motorized hatch allows reconfiguration of the system to allow or prevent the exchange of gases with the atmosphere, and enables the study of fail-safe automation mechanisms. Sensors and actuators measure and intervene to regulate life support variables in the water. The model serves as an analytical reference for future tests in hardware settings, and to test advanced control architectures and policies that enable the system to operate safely and with increasing levels of autonomy, allowing for human intervention if necessary. The goal of the aquatic habitat is to enable life support control concepts that may be challenging to test in larger-scale life support systems. The mathematical description of the dynamic model of the system is presented in this paper with results from simulations of a distributed control approach applied to the habitat.

“…Past projects have made use of aquatic habitats for experiments in zoology and physiology in low Earth orbit (LEO), [10][11][12][13][14] and for ecotoxicological studies in ground-based hardware. 9,15 Such habitats have made use of on/off control (similar to thermostats) to regulate life support variables, and do not necessarily consider all the physiological requirements of their biological elements.…”

Section: A Backgroundmentioning

confidence: 99%

A FAM-based Switched Control Approach for the Automation of Bioregenerative Life Support Systems

41st International Conference on Environmental Systems

2011

The automation of bioregenerative life support systems poses challenges for the development of model-based approaches given the varying characteristic of the biological processes that constitute them. Switching control paradigms offer an alternative for the management of such uncertainty by introducing flexibility into the control path and allowing for different control modes depending on the operational conditions of the system. This paper presents a perception-based switching control strategy that makes use of sensor information to define and act upon those conditions. Abundant sensor information gives rise to sensing spaces in which the operational conditions of the system are found. A decomposition of the sensing spaces into perceptual elements allows for automation and integration strategies, and for the implementation of fail-safe and fail-operational mechanisms. This paper proposes the use of agents based on fuzzy associative memories to decompose sensing spaces into granular structures composed of n-dimensional non-interactive fuzzy sets. The granular structures allow for the incremental development and automation of the system by associating a control task to each granule. The method presented in this paper is applied to the dynamic model of a reconfigurable aquatic habitat. The habitat serves as a small-scale bioregenerative test bed for life support control research. The method used in this paper may also enable cognitive resources to enhance human interaction with the system.