Search Results

This paper introduces two modeling approaches in consideration for the MELiSSA Higher Plants Compartment. This includes an empirical light response curve modeling approach and the Modified Energy Cascade (MEC) model. The MEC model was translated into EcosimPro and evaluated for its performance under a range of environment conditions. The model demonstrated an adequate response to changes on the environmental conditions (temperature, CO2 concentration and light flux) predicting the gas exchange (O2 production, CO2 consumptions, and water vapor transpiration)

The MELISSA (Micro Ecological LIfe Support System Alternative) project of the European Space Agency (ESA) is a tool for the development of a simplified biological life support system. In order to achieve this purpose a loop of four interconnected bioreactors and a higher plant compartment has been designed. The target of the loop is to recycle the wastes, mainly CO2 and organic materials, generated in a closed environment such as in manned space missions, into oxygen, water and edible material. Light is the only energy source used to reach this goal. As a part of the development of the project, a Pilot Plant laboratory has been set up. The role of this pilot plant is to demonstrate the feasibility and robustness of the Melissa concept. In order to study the system two kinds of experiments are required. On one hand, each compartment has to be well characterized and, on the other hand, the performance of the connection between compartments has to be evaluated.

Electrical Impedance Spectroscopy (EIS) consists on the measurement of electrical impedance at different frequencies. The electrical impedance of a biological sample has a specific behaviour with respect to the frequency of the electrical current injected. This behaviour can be distinguished from that of a sample without cells or with dead cells. NTE started the development of this technology in the frame of a project of the European Space Agency (1) and in collaboration with the UPC. This technology has started a technology transfer process, in which three companies from three different fields: a brewery (Freixenet, S.A.), a water treatment plant engineering company (Indeco, S.A.) and a pharmaceutical company (Biokit, S.A.) have evaluated the technology for their production requirements. Specifications were issued for each process considered in case: On-line viable yeast cell determination in CAVA production line.

For long time space missions, a reliable life support system including food supply, gas generation and waste management is necessary. For this purpose the MELiSSA (Micro-Ecological Life Support Alternative) concept has been conceived as a micro-organisms and higher plant based ecosystem intended as a tool for understanding the behavior of artificial ecosystems and for the development of the technology for a future biological life support systems. Based on an aquatic ecosystem, the MELiSSA loop is constituted of four microbial compartments, a higher plant compartment and the crew. The driving element is the recovery of food, water and oxygen from waste, like faeces, urine, non-edible plant material and CO2. Several scientific experiments indicate that a higher microbial growth rate is present in reduced gravity than on earth. This growth rate in reduced gravity can be twice the value obtained on earth.

MELISSA (Micro Ecological Life Support System Alternative) is a research project for the development of advanced life support systems, conducted by the European Space Agency. Its basic design is based on a loop of bioreactors with the main objective of the regeneration of the wastes generated by a crew into an edible material, with concomitant regeneration of the atmosphere for human respiration. The MELISSA Pilot Plant is a European facility to study and validate advanced life support systems. It has as main objectives the ground demonstration and characterization of a closed loop concept. This includes the development of the associated technology for its successful continuous operation such as water treatment, pathogen detection, food preparation, and other related items. At present time, the main research project developed in the Pilot plant is the MELISSA project.

Successful implementation of the MELISSA loop requires the optimum performance of each of its compartments. Preliminary studies on the behaviour of the photoheterotrophic compartment have been performed. The previously suggested strains have been tested for growth on the carbon and nitrogen sources expected to be components of the influent. The results indicate that of the organisms tested Rs.rubrum should become the organism of choice for the photoheterotrophic compartment while R.capsulatus is more appropriate for the photoautotrophic anaerobic compartment. Biomass analyses, determination of yields and growth rates have also been performed in the preliminary batch and continuous cultures.