MSL-LGF: High temperature materials research onboard the ISS by means of resistance heated furnaces
The ESA Materials Science Laboratory (MSL) provides an experiment module for materials science research onboard the International Space Station (ISS). 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 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 and engineering models two Science Reference Models were developed for the preparation and pre-validation of the experiments on the ground. MUSC - located at the Institute of Materials Physics in Space, DLR, Cologne, Germany - in its function as the Facility Responsible Center for MSL-LGF carry out the experiment related tasks related to preparation and in-flight operation of multi-user payloads. MSL is designed to be integrated in the Materials Science Research Rack (MSRR-1) host facility provided by NASA in the US-Lab ‘Destiny’ of the ISS. Presently it is planned to launch MSRR-1 and MSL with the furnace insert LGF in the timeframe of the year 2008.
|The MSL-LGF insert. |
Main furnace parameters
- Heater element assemblies
- Thermal insulation (Temperature uniformity along the circumference of each heater zone: variation of up to ± 0.5°C)
- Temperature stability about ± 0.02°C at T< 1000°C/ about ± 0.05°C at T< 1200°C / about ± 0.1°C at T< 1400°C
- Thermal gradient up to 40K/cm
- LGF maximum operating temperature 1400 °C
- T/C electronics: 16 bit resolution, accuracy: ± 30 µV, T/C accuracy: 1% of T
- Water cooled jacket
- Electromagnet (magnetic field strength ~ 7.6 mT DC, ~ 4.1 mT at 100 Hz, ~ 1.5 mT at 400 Hz; Magnetic field frequency 5 – 400 Hz settable in 1Hz steps)
- Heated volume with 370 mm length and 30 mm diameter
- Two hot cavities separated by 40mm adiabatic zone
- LGF mass is 35 kg
- Designed for vacuum operation