Materials Science Laboratory

MSRR-1 (NASA)

The Materials Science Laboratory (MSL) of the European Space Agency is a payload onboard the International Space Station. It was launched with Space Shuttle Discovery on its STS-128 mission.

It is installed in NASA's first Materials Science Research Rack which is placed in the Destiny laboratory onboard the ISS. Its purpose is to process material samples in different ways: 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.

MSL was built for ESA by EADS Astrium in Friedrichshafen, Germany. It will be operated and monitored by the Microgravity User Support Center (MUSC) of the German Aerospace Center (DLR) in Cologne, Germany.

Core Facility

The Materials Science Laboratory (MSL) facility is the contribution of the European Space Agency to NASA's MSRR-1. It occupies one half of an International Standard Payload Rack.

The MSL consists of a Core Facility, together with associated support sub-systems. The Core Facility consists mainly of a vacuum-tight stainless steel cylinder (Process Chamber) capable of accommodating different individual Furnace Inserts (FIs), within which sample processing is carried out. The processing chamber provides an accurately controlled processing environment and measurement of microgravity levels. It can house several different Furnace Inserts. During the first batch of experiments the Low Gradient Furnace (LGF) is installed. Another furnace, the Solidification and Quenching Furnace (SQF) is already produced and waiting on ground for future operations. The Fi can be moved with a dedicated drive mechanism to process each sample according to requirements from the Scientists. Processing takes place normally under vacuum.

The Core Facility supports FIs with up to eight heating elements, and provides the mechanical, thermal and electrical infrastructure necessary to handle the FIs, the Sample Cartridge Assembly (SCA), together with any associated experiment-dedicated electronics that may be required.

A FI is an arrangement of heating elements, isolating zones and cooling zones contained in a thermal insulation assembly. On the outer envelope of this assembly is a water-cooled metal jacket forming the mechanical interface to the Core Facility.

The major characteristics of the two produced Furnace Inserts are:

• Low Gradient Furnace (LGF)

The LGF is designed mainly for Bridgman crystal growth of semiconductor materials. It consists of two heated cavities separated by an adiabatic zone. This assembly can establish low and precisely controlled gradients between two very stable temperature plateaux.

• Solidification and Quenching Furnace (SQF)

The SQF is designed mainly for metallurgical research, with the option of quenching the solidification interface at the end of processing by quickly displacing the cooling zone. It consists of a heated cavity and a water-cooled cooling zone separated by an adiabatic zone. It can establish medium to steep temperature gradients along the experiment sample. For creating large gradients, a Liquid Metal Ring enhances the thermal coupling between the SCA and the cooling zone.

Sample Cartridge Assembly

The samples to be processed are contained in experiment cartridges, the SCAs, that consist of a leak-tight tube, crucible, sensors for process control, sample probe and cartridge foot (i.e. the mechanical and electrical interface to the process chamber). The MSL safety concept requires that experiment samples containing toxic compounds are contained in SCAs that support the detection of potential leaks. The volume between the experiment sample and the cartridge tube is filled with a pre-defined quantity of krypton, allowing leak detection by mass spectrometry. However the first batch of experiments does not contain any toxic substances.

Up to 12 scientific thermocouples provide the sample's temperature profile and allow differential thermal analysis.

External Links

• MSL Website of DLR
• MSRR-1 Website of NASA
• ESA's MSL website