Design of a test platform for algae cultivation research at different gravitation levels

As a contribution to closed regenerative life support systems for future space exploration, the EU Horizon 2020 project TIME SCALE develops an advanced life support system concept to allow life science research and technology demonstrations under fractional gravity conditions. The project is based on the European Modular Cultivation System (EMCS), an experiment platform to study biology and perform technology demonstrations at different gravitation levels (e.g. lunar gravity), and develops concepts and hardware with applicability for both payloads on the International Space Station and for life support systems beyond. The project is carried out in the frame of Horizon 2020 by eight European consortium partners: Norges Teknisk-Naturvitenskapelige Universitet (NTNU), Wageningen University, Universiteit Gent, Universität Stuttgart, Design and Technologies for High Performance Mechanics (DTM), Interscience Belgium/Netherlands, Prototech AS, Cleangrow LTD. This paper presents the concept developed by the University of Stuttgart for an Algae Cultivation Compartment (ACC). Two major designs are proposed: a technology demonstrator and a fundamental biology research platform. The technology demonstrator design includes powerful lighting, temperature control, gas supply and a water-nutrient-management system. The aim of this system is to grow biomass fast, allowing for a systemic assessment focused on gas-turnover rates and growth speed, allowing a quick comparison of different bioreactor designs, upstream procedures, nutrient compositions, and algae species at the target gravity level. The biology research platform contains several cassettes including agar plates for algae growth. The goal is the investigation of single algae cells in a strictly controlled environment, allowing for fundamental research, investigating direct correlations between growth conditions (e.g. lighting spectrum, gas composition) and cell expression. Every cell cluster is separately illuminated, and each test chamber can operate with a different gas composition.