E-USOC Intranet



Brief Summary


Source: Verhaert

Selectable Optical Diagnostics Instrument (SODI) is an ESA research project planned to be performed in a NASA facility, the Micro-gravity Science Glove Box (MSG), on the ISS. The basic principle of SODI design is to have a modular instrument to be accommodated in the MSG, where three SODI experiments are going to be performed: IVIDIL, DSC and COLLOID. SODI will be equipped with various optical diagnostics, such as Mach-Zehnder Interferometer, Particle Image Velocimetry and Near Field Scattering which will allow to study:
  • The diffusion phenomena and Soret effects in liquids and investigate the influence of vibration stimuli on these phenomena (DSC and IVIDIL)
  • The aggregation of colloidal solutions (COLLOID)

These three SODI experiments have their own dedicated cell array(s) which will be mounted into the SODI facility by the ISS crew. E-USOC, appointed for SODI as Experiment Support Centre (ESC) for SODI-IVIDIL and SODI-COLLOID, is in charge to prepare and execute the operations of these experiments, and as such E-USOC responsibilities are: operations products development and update (e.g. PODF, experiment scripts, planning products) and further coordination, ground models operations (MSG EU and MEDU), support in the definition of the respective experiment plans, provide the respective PIs (Principal Investigators) with the scientific data from their experiments, and support their later evaluation (e.g. data processing and analysis). Broadly, E-USOC monitors, commands and coordinates this Payload in Real-Time operations.

Significant Dates

  • Mission STS-128/17A, Increment 19/20: August 28th, 2009 – upload allocation and physical configuration during launch
  • Mission ULF3, Increment 21/22: 2009 – planned download

Experiment/Payload description


Source: Verhaert

In real space experiments the benefit of the free fall condition may be altered by residual gravity vibration (also known as g-jitter). It is caused by aerodynamic forces, onboard equipment and, in the case of manned platforms, by crew movements. Although it is recognized that g-jitter may have a major impact on diffusion and thermal diffusion measurements, very few experiments have been carried out in the past.
Even if the overall forces caused by the above disturbances are still relatively small (ranging from 10-2 to 10-6 times the normal gravity), the effect may be non negligible for long duration experiments such as the ones that involve diffusion limited phenomena. Purpose of the project is to measure thermal and isothermal diffusion coefficients in binary systems subjected to controlled vibration under different values of amplitude and frequency. There exist a number of numerical codes to assess for studying the effect of residual gravity and vibration, but their reliability is difficult to assess due to lack of experimental investigations.
The IVIDIL project should therefore provide reference data for the validation and testing of numerical codes. In summary, the goals of the IVIDIL experiment are:

Source: Verhaert

  1. To investigate the impact of vibrations on the measured thermal and isothermal diffusion coefficient in a controlled way. The measurements will be repeated at different amplitude and frequency in order to validate the results.
  2. To validate the measurement technique to be used by petroleum industries or in a ISS application program at low residual gravity level.
  3. To verify the numerical modeling of the vibration impact on the diffusion processes in the range 0.05-2.8 Hz.
The IVIDIL experiment will be performed in two cell arrays each composed of two cells: the primary cell that is probed by MZI and the companion cell that is filled with tracer particles and is probed by digital holography for PIV. Over the experiment run, the cells are temperature controlled.