Columbus space laboratory

It is supposed to be perfectly round: heated by electromagnetic fields and held in suspension, free of the effects of gravity, the metal drop at 1,500° Celsius will form a perfect sphere. If the same electromagnetic fields force it to take another shape, the deviance from the ideal will reveal something about the internal forces of the melt. Professor Andreas Meyer, materials scientist at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt – DLR) in Cologne, wants to find out exactly how, for instance, aluminium-titanium alloys react when heated in terms of expansion, surface tension and viscosity.

He also hopes to discover the influence of the fluid flow and concentrations of the individual elements as melts solidify. This information will help generate more precise models for the simulation of metal casting processes on the computer, which in turn will accelerate the development of new materials and casting processes, for example for turbine blades or engine blocks. Meyer, who heads the DLR Institute for Materials Physics in Space, explains that the intention is not to examine how weightlessness influences these physical processes, but to reduce gravity’s interference on the flow of material in the melt. Because there are no machines which can switch off gravity, researchers need the weightlessness of space.

Launched on 7 February 2008 with the Atlantis space shuttle to the International Space Station ISS, the European space laboratory Columbus is now available for their experiments. It was mounted permanently on the ISS within four days and connected to the electricity supply, the air conditioning and the computer system. The module is almost seven metres long and 4.5 metres in diameter, providing space for up to 16 racks, as the cupboards for the experimental equipment are called. Platforms on the outer wall make it possible to examine the influence of free space directly. The Europeans have invested 880 million euros and can claim 51 per cent of the laboratory capacity. “In order to make best use of Columbus during its projected ten-year lifespan, only the most important experiments are selected for the space lab,” Andreas Meyer explains, adding that projects are selected in a tough European competition. Projects only have a chance of succeeding on this level if they are the product of a lively international exchange of views and intensive collaboration.

130 experiments are already planned and the first began within a few days of the space lab docking on to the ISS. In the Biolab, for example, molecular biological methods are used to examine how micro-organisms, plants and invertebrates perceive and deal with gravity. DLR scientist Professor Rupert Gerzer, head of the Institute for Aerospace Medicine in Cologne, is in charge of the analysis of space radiation and its effects on the human organism. Physicists and engineers are more interested in inanimate materials. In the Geoflow project, for example, they are attempting to increase their understanding of the currents in the earth’s molten outer core, using a small model.

The Levitator, which is intended to generate the electromagnetic fields for the perfectly spherical melt, is not yet on board. DLR materials scientist Meyer, whose institute is involved in ten projects and in charge of five of them, will have to wait until 2009 and 2011 to start his space experiments. They are, however, already working hard preparing the Columbus experiments. The ESA has also approved his institute responsibility for preparing and conducting all the experiments which take place in the Materials Science Lab of the Space Laboratory. All the experimental equipment will be thoroughly tested and automated using parabolic flights and full-scale models to make work for the astronauts as easy as possible. After all, they do not have much time. Most of the work is monitored and carried out from the Microgravity User Support Center in Cologne.

The DLR also directs the overall activity in the space lab from the European Columbus Control Centre in Oberpfaffenhofen. Although it has only just begun, the researchers have to think ahead. “Science in space itself is not our goal,” Meyer emphasises. “We intend to make use of the resource space in the limited time and restricted area available to us to make significant scientific advances and to learn as much as we can for future experiments back on earth.” – for the time after Columbus.