Two life support-related studies: LARISS experiment and moon illumination calculator

Abstract: In order to carry long-term manned space exploration, closed-loop life support systems are developed at ESA to enable recycling of wastes into oxygen and food. These systems involve the use of regenerative processes. Two studies are presented in this framework. The first one concerns the development of an experiment to be flown onboard the International Space Station. It aims to assess the space environment effects on a micro-organism involved in an oxygen recycling process of a life support system, as well as in the food chain. It also aims to assess relevant technologies to maintain the culture and monitor measurements, which has not yet been done for a space application. It features as well an educational part to teach a group of European students about life support systems. The steps to reach the final design are presented, on both technical and procedural points of view. A set of requirements is being defined, and a first draft design is presented for a feasibility study. It involves a hardware description of a photobioreactor together with its flight support equipment, and an associated flight procedure. It is evaluated considering constraints imposed by the Science, the crew availabilities, the resources for implementation and potential interfaces, the safety aspects. Knowledge of such constraints is continuously updated through frequent meetings with each of the parties involved. A set of three papers has been written in the frame of this preparation. After approval of the mission feasibility, contact is undergone with a contracting company to develop a deepened comprehensive preliminary experiment design. Its status follows imposed requirements, advices, and is closely followed up. It is presented up to Preliminary Design Review level. The assessed design at the Review's output still requires a short size and mass shrinking for implementation due to Soyuz module transportation constraints, and would then be ready for manufacturing and testing.The second study regards the case of lunar life support systems for manned exploration. It is envisaged in the long term to have a permanent outpost at the South Pole of the Moon, where settlers will be supported by greenhouse cultures. A precursor unmanned mission known as MoonNEXT is to be flown in the next few years to investigate a potential landing site. It will feature a small coupled bacterial system on top of a Lander as a lunar life support experiment. In both cases of greenhouse and small experiment, knowledge of the available light at the landing site is crucial to size the system. A numerical tool to assess available light at potential landing sites is asked to be developed. It is programmed with Excel and its Visual Basic coding possibility. The model has two inputs: a date and a lunar site among four possible, selected based on previous studies. It first calculated the solar flux reaching the Moon at the given date using orbital dynamics. It then considers the topography surrounding the selected site and assesses if it is susceptible to hide the solar disk. This step is based on a comparison between a solar elevation model (built for the occasion) and a terrain elevation model (using available data). A comparative study of available illumination impact on life support systems is then performed for a small experiment and a greenhouse case, and design solutions are suggested to size those systems at best. The tool's interface is interactive, adaptive (possibility to extend the model to other sites) and fully ready for use. It will support mission scenario design for the phase B of the MoonNEXT project.