Materials science research aboard the International Space Station (ISS) rests on two major facilities, the Electro-Magnetic Levitator (EML) and the Materials Science Lab (MSL).
The EML is installed in the European Columbus module of the ISS. Preparatory experiments are performed on the sounding rocket TEXUS and in the facility TEMPUS on parabolic flights. Both the MSL and the EML aim at research in solidification, crystal growth, and diffusion of mass, as well as the thermophysical properties of metals. Preparation, execution, and evaluation of the initial experiment batches in space are coordinated by the Institute of Materials Physics in Space within DLR’s Microgravity User Support Center.
The Materials Science Laboratory (MSL) of the European Space Agency (ESA) provides an experiment module for materials science research onboard the International Space Station (ISS). MSL is integrated in the Materials Science Research Rack (MSRR-1) host facility provided by NASA in the US-Lab ‘Destiny’ of the ISS. MSL was launched with Space Shuttle Discovery on STS-128 mission at the end of August 2009.
The MSL payload allows experiments in the fields of directional solidification of metals and alloys, crystal growth of semi-conducting materials, thermo-physical properties and diffusion experiments of alloys and glass-forming materials, and investigations on polymers and ceramics at the liquid-solid phase transition.
Two Bridgman-type furnace inserts have been developed to cover the scientific fields of MSL, the Low Gradient Furnace (LGF) and the Solidification & Quenching Furnace (SQF). The SQF was developed with the design goal to provide a temperature gradient more than 100K/cm, whereas the LGF is designed to provide thermal gradients in the range up to 50K/cm. Several subsystems and diagnostic devices are provided like a rotating magnetic field at the adiabatic zone of the furnaces, as well as Ultrasound diagnostics for additional scientific investigations. Beside the flight (FM) and engineering model (EM) two Science Reference Models (SRM) were developed for the preparation and pre-validation of the experiments on the ground. MUSC - located at the DLR, Cologne, Germany in its function as the Facility Responsible Center for MSL carry out the experiment related tasks related to preparation and in-flight operation of multi-user payloads.
For more information, see also ESA's MSL website.
The electromagnetic levitator (EML) is a multi user facility onboard the ISS, which was installed in 2014 by A. Gerst. In this facility a conductive sample is placed in a coil and processed containerless, heating and positioning is performed by two independent fields. This enables the scientists to process the sample without contact to a crucible and with low magnetic field strengths compared to ground based levitation.
As the experiments are quite complex an extensive ground support program is needed to prepare those experiments. In a first step the samples are characterized. The necessary parameters for the planning are measured in a facility with the same coil system and optical path for the pyrometer. So the reaction of the sample to the heater field, cooling rates etc. can be determined. With these parameters the experiment parameter sets are developed with a software simulation tool in cooperation with the scientists. When the parameter sets are established they are validated in the EML-OM (Operational Model), which is flightlike and provides the same properties as the flight model. These validated parametersets are then ready for the upload to the ISS.
The experiments are carried out with the microgravity user support center (MUSC) from the control room in cologne. The scientists are on site during the experiment runs and can optimize their experiments by commanding from ground. The facility was commissioned in 2014 and first scientific experiments were started in 2015. The EML sample chamber contains 18 samples (called a sample batch). The processing of Batch 1 is finished and the experiments of Batch 2 are ongoing in orbit. Meanwhile also the ground support program for Batch 3 has started.
For parabolic experiments with the A310 of Novespace the institute operates the TEMPUS (Tiegelfreies elektromagnetisches Prozessieren unter Schwerelosigkeit) facility. Experiment campaigns are typically performed once per year and contain three or four flight days with 31 parabolas each.