Materials Science Laboratory

The Materials Science Laboratory (MSL ) is an experiment of the European Space Agency onboard the International Space Station. It was launched in August 2009 as part of the STS -128 mission, the Space Shuttle Discovery. Monitored and controlled by the user, the MSL Centre for Space Experiments ( MUSC ) of the German Aerospace Center (DLR ) in Cologne. The scientific ground events will be conducted by the Institute of Materials Physics in Space.

Mission History

MSL was transported as part of the STS -128 mission on 29 August 2009 with the Space Shuttle Discovery to the ISS and transferred to the Destiny module. In October 2009, MSFD -1 and MSL activated for the first time and presented their functionality to the test. In early November, the first two experiments could be carried out successfully. The experiment samples to be returned with the shuttle mission STS -129 to the ground and then analyzed by the researchers. In the first half of 2010, the remaining eleven samples of the first series of experiments (batch 1) are processed. Further experiments are already in the planning stage (batch 2).

Purpose

MSL is used for melting and solidification of conductive metals, alloys and semiconductors in the extreme vacuum or in high-purity inert gas environments in weightlessness. In addition to experiments to better understand the effects of weightlessness on the microstructural evolution of metals in casting processes, the system opens up new possibilities for the study of thermophysical properties of alloys and glass-forming materials, as well as the solid-liquid phase transitions in polymers and ceramics. The aim of the study is to, (atomic ) to expand the understanding of transition processes, structures and material properties so that the calculation models can be improved. So to previous production methods refined, improved products and can develop new ones.

MSL is the only experiment in the NASA Materials Science Research Rack, which is installed on the ISS in the Destiny laboratory. The integration of the rack was initially planned for the European Columbus research module, but was postponed in the meantime on the American laboratory. The remote controlled operation of the facility and the implementation of the scientific ground support program is the responsibility of ESA and carried out by the user center for space experiments ( MUSC ) of the German Aerospace Center (DLR ) in Cologne. The crew activity in space is limited next maintenance mainly due to the onset of the experiment cartridges and the connection of these. To the measurement electronics

Construction

MSL consisting of a core element and a number of auxiliary systems. The core member is mainly composed of an air-tight stainless steel chamber which can be put under vacuum. To perform various experiments, it can accommodate various furnace elements in which the samples are processed.

The chamber provides a precisely controlled environment ready for the experiments. The oven racks can be operated by two different drives either very slowly or very quickly over the sample. It may include up to eight heating zones that can be controlled separately. In addition, a precise to generate a controlling magnetic field generator, a corresponding field in the samples. The experiments are carried out under vacuum. The contents of the chamber is released at the beginning into space and then provide turbomolecular pumps to ensure that the vacuum is maintained during processing under 10-4 mbar.

Currently, two Öfeneinschübe are available, one of which (Low Gradient Furnace - LGF ) is for the first set of experiments in space. The second furnace ( Solidification and Quenching Furnace - SQF ) is started later for the next experiments.

A furnace unit consists of heating elements, insulation zones, cooling zones, and is encased in an insulating housing. On the outside, provide a variety of connections to the electrical and cooling water connection here to the plant.

Rehearse

The samples are included in special containers, the Sample Cartridge Assemblies - SCA. They consist of a thick tube, a crucible, various sensors, and a head which establishes the mechanical and electrical contact with the plant. MSL is generally also able to process toxic samples. These have to contain krypton. During the experiments, a mass spectrometer then examined for traces of gas in the main chamber so as to preclude leakage. However, the currently planned experiments include no toxic samples.

For scientific monitoring of the experiments are installed in the up to twelve SCAs temperature sensors.

Experiments

The first MSL experiments were carried out in the framework of the ESA MAP ( Microgravity Application Program). The ESA MAP projects are public- private partnerships between industry, universities, research institutions and national agencies.

The projects CETSOL ( Columnar to equiaxed transition in Solidification Processing) and MICAST ( Microstructure Formation in Casting of Technical Alloys under Diffusive and Magnetically Controlled Convective Conditions) examine different patterns of growth and development of the microstructure during solidification of aluminum alloys. The aim is a better understanding of the parameters and processes which influence the solidification of molten metals. Using the results of numerical models should be reviewed for prediction of the internal structure of castings and further developed. This serves to optimize previous casting process, to finally obtain products with improved material properties and selectively adjusted.

The experiment CETSOL deals with the study of basic physical phenomena during the solidification of molten metals and their effects on the material properties.

MICAST examines the emergence and development of microstructures during solidification of technical aluminum alloys under the influence of currents, such as those occurring during casting. In the experiment, the currents are simulated by a rotating magnetic field and compared the results with in zero gravity, flow freely solidified samples.

These experiments can be carried out on the ISS, because only here long enough weightlessness is available to investigate the issues. The research on the ISS allows controlled and well-defined processes experiment, without the disturbing influence of gravity and thus provides ideal conditions for basic research.