Figure 4

In-flight-experiment system during parabolic flights on board the Airbus A300 ZERO-G. a: Experiment hardware structure which consists of an incubator rack to store the cell containers temporarily before the experiment at 37°C (1), an experiment rack, in which all active aggregates are accommodated for the execution of the experiment and where the living cells are handled during altered gravity (2) and a cooling rack to store temporarily all cell containers after the injection of the stop/fixation liquid at 4°C until landing (3). b. Structure of the working rack, rear side. In range A (4°C) are three separate hose pumps, which pump one of the two possible stop liquids (e.g. ethanol or 4% formaldehyde) into the cell containers. The pumps are activated and regulated by the control unit inside range C, which also carries all electrical connections and fuse elements. All liquids are sucked under exclusion of air. Inside range B (37°C) are three bags with activator liquids, connected to three separate hose pumps, which pump the activator solution into the cell container upon activation of the individual experiment. c. Structure of the working rack, front side. Range D is the actual working space with three cell containers in parallel, which are connected to the activator and fixation liquid bag. Range D is also waterproof and the door position is controlled by a safety switch (sensor). Activation of the experiment is only possible when the front door is closed. d. Double-wall liquid-proof cell container. A maximum of 60 container can be accommodated during one flight. 1 = plastic container, 2 = air valve, 3 = internal sterile cell culture bag (Nutrimix 0.25l), 4 = connector 1 (activator liquid), 5 = connector 2 (stop/fixation liquid), 6 = connector 3 (filling port for cells, performed preflight), 7 = plastic flange. e. Fluid loop diagram for one cell container. The entire experiment system has three identical fluid loops.