Search Results

The biological autonomy of man when isolated from his original biosphere can be ensured only by Biological Life Support technologies. Among these, bioreactors are of prime importance and can be divided into two main groups: biomass producing bioreactors and materials transforming bioreactors. The latter case requires, if possible, high concentrations of active cells, in order to obtain a maximum efficiency in the transformation of substracts to products. One way to obtain such objectives is to immobilise the microorganisms. Specific and precise tools are required to control continuously the immobilised biomass. Among them there is a biomass monitor able to measure both free and immobilised biomass concentration. Such a monitor has been developed by Nuevas Tecnologías Espaciales (NTE) in collaboration with the Chemical Engineering Unit of the Universitat Autònoma de Barcelona (UAB) under the Technology Research Programme (TRP) of the European Space Agency (ESA).

The MELISSA (Microbial Ecological LIfe Support System Alternative) project has been set up to be a model for the studies on ecological life support systems for long term space missions. The compartmentalisation of the loop, the choice of the micro-organisms and the axenic conditions have been selected in order to simplify the behaviour of this artificial ecosystem and allow a deterministic and engineering approach. In this framework the MELISSA project has now been running since beginning 1989. In this paper we present the general approach of the study, the scientific results obtained on each independent compartment (mass balance, growth kinetics, limitations, compound conversions,..), the tests of toxicity already performed between some compartments and their effect on the growth kinetics. The technical results on instrumentation and control aspects, and the current status of the ESA/ESTEC hardware are also reviewed.

This work was to provide the European Space Agency (ESA) with technical and architectural guide-lines for the eventual building of a Closed Ecological System Test Bed. This work had three successive targets. The first target has been the definition of the general objectives and the specific requirements for a closed ecological system test bed. It shall have the appropriate flexibility which will enable the users to perform separately and/or in parallel, multiple tasks. Indeed, some biological life support units may also be investigated as specific support to the currently on-going European manned space projects. In addition, some concepts for the test bed have been defined taking into account the rather contractory needs for a sealed structure and for structural and functional flexibility. One of them has been the subject of a preliminary architectural definition which is presented with some detail.