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This work presents the preliminary characterization of the vibrational environment of the DCMIX4 thermodiffusion experiment conducted onboard the ISS from December 2018 to March 2019. Given the long duration of each one of the 58 runs of the campaign and to ensure a correct interpretation of the results, an accurate analysis of acceleration levels all along the experiment is advisable. Digital signals coming from the nearest sensor, es09006, located in the Microgravity Science Glovebox (Destiny module) were downloaded from the PIMS NASA website. The techniques used to identify the main disturbances during the experiments were defined both in time and frequency domains. It is expected that the results obtained can help the experimentalist to have an overview of the possible sources of disturbances that may affect their experiments. To visualize the possible impact of the accelerometric environment on the experiment a numerical simulation has been performed. Four signals have been chosen, one considering the ideal case g = 0, one coming from the OSS raw sensor (outside the Microgravity Science Glovebox) and the other two, coming from the es09006 sensor that needed to be mathematical manipulated for considering only the low frequency range. Independent of the location of the sensor, numerical simulations do not detect, in any case, appreciable flow disturbances if quiescent periods are considered. Therefore, in case the reference sensor is not available one can use other sensors placed in the same module., SCOPUS: ar.j, DecretOANoAutActif, info:eu-repo/semantics/published

publicat online: https://doi.org/10.1007/s12217-018-9598-5, We report on thermodiffusion experiments conducted on the International Space Station ISS during fall 2016. These experiments are part of the DCMIX (Diffusion and thermodiffusion Coefficients Measurements in ternary Mixtures) project, which aims at establishing a reliable data base of non-isothermal transport coefficients for selected ternary liquid mixtures. The third campaign, DCMIX3, focuses on aqueous systems with water/ethanol/triethylene glycol as an example, where sign changes of the Soret coefficient have already been reported for certain binary subsystems. Investigations have been carried out with the SODI (Selectable Optical Diagnostics Instrument) instrument, a Mach-Zehnder interferometer set up inside the Microgravity Science Glovebox in the Destiny Module of the ISS. Concentration changes within the liquids have been monitored in response to an external temperature gradient using phase-stepping interferometry. The complete data set has been made available in spring 2017. Due to additionally available measurement time, it was possible to collect a complete data set at 30 ◦C and an almost complete data set at 25 ◦C, which significantly exceeds the originally envisaged measurements at a single temperature only. All samples could be measured successfully. The SODI instrument and the DCMIX experiments have proven reliable and robust, allowing to extract meaningful data even in case of unforeseen laser instabilities. First assessments of the data quality have revealed six out of 31 runs with some problems in image contrast and/or phase step stability that will require more sophisticated algorithms. This publication documents all relevant parameters of the conducted experiments and also events that might ha

publicat online https://doi.org/10.1007/s12217-018-9640-7, A comparative analysis of the vibratory environment of the DCMIX2/3 thermodiffusion experiments is presented here by using acceleration signals coming from different sensors placed in the Destiny, Columbus and Kibo modules. The es03 sensor, nearest to the experimental device and located inside the Glovebox (Destiny module) has been defined as reference. Data were downloaded from the NASA PIMS website paying special attention to the runs coinciding with disturbances such as dockings or extravehicular activities (EVAs) as they could particularly affect the International Space Station (ISS) microgravity levels. The analyses have been made minute by minute for the three acceleration components by using the Frequency Factor Index (FFI), Spectral Entropy (SEN) and Root Mean Square (RMS) values evaluated over one-third-octave frequency bands. Spearman's rank correlation coefficient and the coherence function have been used to investigate the degree of linear correlation between the reference signal and the other ones. SEN evolution showed different patterns compared to the reference. Also, RMS values surpassing the ISS microgravity limits were detected in all sensors, mainly at low frequency bands (<10 Hz) and prevailing on zA direction. However the sensors located in the Destiny module better accomplished the ISS vibratory limits requirements. Finally, some degree of linear correlation at structural frequencies (< 3Hz) has also been detected. Overall, the sensors placed in the Destiny, Columbus and Kibo modules presented different vibratory characteristics and, despite they offer valuable information of the whole environment, may not be sufficient properly characterize DCMIX2/3 experiments.

DOI: https://doi.org/10.1007/s12217-018-9612-y, The present work aims to investigate the degree of correlation existing between the information contained in the ISS reduced quasi-steady accelerometric data and different external mechanical disturbances (reboostings, dockings/undockings, berthings/deberthings and Extra Vehicular Activities), compiled for the period 2009 to 2016. The eight hour mean (Mean8h) and the eight hour root mean square (RMS8h) acceleration values, considered as reduced data, have been extracted from the quasi-steady records provided by NASA Principal Investigator Microgravity Services website. The advantage of applying the present strategy is to drastically reduce the amount of information to be processed all along these eight years. The Mean8h values have been used for the evaluation of trends as function of time while the RMS8h ones were used to define the level (weak, medium and strong) of the different kind of external mechanical disturbances considered. These criteria has been applied for approximately four hundred selected disturbances, compiled in the Annex. Results indicate that reboosting is always detected as a strong disturbance, while dockings/undockings, as weak ones, having lower, though detectable level, depending on the type of spacecraft considered. Extra Vehicular Activities are undetectable by the use of this reduced quasi- steady approach. The inverse problem, in other words, knowing the value of the RMS8h one could try to predict the kind of disturbance responsible of it, is thus feasible except for berthing/deberthings and Extra Vehicular Activities.

A comparative analysis of the vibratory environment of the DCMIX2/3 thermodiffusion experiments is presented here by using acceleration signals coming from different sensors placed in the Destiny, Columbus and Kibo modules. The es03 sensor nearest to the experimental device and located inside the Glovebox (Destiny module) has been defined as reference. Data were downloaded from the NASA PIMS website paying special attention to the runs coinciding with disturbances such as dockings or extravehicular activities (EVAs) as they could particularly affect the International Space Station (ISS) microgravity levels. The analyses have been made minute by minute for the three acceleration components by using the Frequency Factor Index (FFI), Spectral Entropy (SEN) and Root Mean Square (RMS) values evaluated over one-third-octave frequency bands. Spearman’s rank correlation coefficient and the coherence function have been used to investigate the degree of linear correlation between the reference signal and the other ones. SEN evolution showed different patterns compared to the reference. Also, RMS values surpassing the ISS microgravity limits were detected in all sensors, mainly at low frequency bands (< 10 Hz) and prevailing on zA direction. However the sensors located in the Destiny module better accomplished the ISS vibratory limits requirements. Finally, some degree of linear correlation at structural frequencies (< 3 Hz) has also been detected. Overall, the sensors placed in the Destiny, Columbus and Kibo modules presented different vibratory characteristics and, despite they offer valuable information of the whole environment, may not be sufficient to properly characterize DCMIX2/3 experiments., SCOPUS: ar.j, info:eu-repo/semantics/published

We report on thermodiffusion experiments conducted on the International Space Station ISS during fall 2016. These experiments are part of the DCMIX (Diffusion and thermodiffusion Coefficients Measurements in ternary Mixtures) project, which aims at establishing a reliable data base of non-isothermal transport coefficients for selected ternary liquid mixtures. The third campaign, DCMIX3, focuses on aqueous systems with water/ethanol/triethylene glycol as an example, where sign changes of the Soret coefficient have already been reported for certain binary subsystems. Investigations have been carried out with the SODI (Selectable Optical Diagnostics Instrument) instrument, a Mach-Zehnder interferometer set up inside the Microgravity Science Glovebox in the Destiny Module of the ISS. Concentration changes within the liquids have been monitored in response to an external temperature gradient using phase-stepping interferometry. The complete data set has been made available in spring 2017. Due to additionally available measurement time, it was possible to collect a complete data set at 30∘C and an almost complete data set at 25∘C, which significantly exceeds the originally envisaged measurements at a single temperature only. All samples could be measured successfully. The SODI instrument and the DCMIX experiments have proven reliable and robust, allowing to extract meaningful data even in case of unforeseen laser instabilities. First assessments of the data quality have revealed six out of 31 runs with some problems in image contrast and/or phase step stability that will require more sophisticated algorithms. This publication documents all relevant parameters of the conducted experiments and also events that might have an influence on the final results. The compiled information is intended to serve as a starting point for all following data evaluations., SCOPUS: ar.j, info:eu-repo/semantics/published

Two accelerometric records coming from the SAMSes es08 sensor in the Columbus module, the so-called Runs 14 and 33 in terms of the IVIDIL experiment, has been studied here using standard digital signal analysis techniques. The principal difference between both records is the vibrational state of the IVIDIL experiment, that is to say, during Run 14 the shaking motor of the experiment is active while that in Run 33 this motor is stopped. Identical procedures have been applied to a third record coming from the SAMSII 121f03 sensor located in the Destiny module during an IVIDIL quiescent period. All records have been downloaded from the corresponding public binary accelerometric files from the NASA Principal Investigator Microgravity Services, PIMS website and, in order to be properly compared, have the same number of data. Results detect clear differences in the accelerometric behavior, with or without shaking, despite the care of the designers to ensure the achievement of the ISS μg-vibrational requirements all along the experiments. © 2013 IAA., SCOPUS: ar.j, info:eu-repo/semantics/published

The present work aims to study mechanical nonlinearities detected in the accelerometric records during a thermodiffusion experiment performed at the International Space Station, ISS. In that experiment the test cell was subjected to harmonic vibrations of different frequencies and amplitudes. Accelerometric data associated to the runs were downloaded from NASA PIMS website. Second order spectral analysis shows that the shaker modifies the normality of the data and introduces nonlinearities in the distribution of energy. High Order Spectral Analysis, HOSA, based on the bispectrum, bicoherence, trispectrum and tricoherence functions enabled us to study the kind of these nonlinearities. Additionally, a new method using the biphase and triphase histograms helps us to assess if quadratic and/or cubic phase coupling mechanisms are responsible for the anomalous nonlinear energy transfer detected. Finally, the RMS acceleration values are investigated to check if the vibratory limit requirements of the ISS are exceeded. This methodology is important not only in generic research of aerospace engineering but also in space sciences in order to help space researchers to characterize more globally their experiments. It is mentioned finally that HOSA techniques are not new, but never have been used in the analysis of accelerometric data coming from the ISS. © 2014 IAA., SCOPUS: ar.j, info:eu-repo/semantics/published

Two accelerometric records coming from the SAMSes es08 sensor in the Columbus module, the so-called Runs 14 and 33 in terms of the IVIDIL experiment, has been studied here using standard digital signal analysis techniques. The principal difference between both records is the vibrational state of IVIDIL, that is to say, during Run 14 the shacking motor of the experiment is active while that in Run 33 this motor is stopped. Identical procedures have been applied to a third record coming from the SAMSII 121f03 sensor located in the Destiny module during an IVIDIL quiescent period. All records have been downloaded from the corresponding public binary accelerometric files from the NASA Principal Investigator Microgravity Services, PIMS website and, in order to be properly compared, have the same number of data. Results detect clear differences in the accelerometric behavior, with or without shaking, despite the care of the designers to ensure the achievement of the ISS pg-vibrational requirements all along the experiments. Copyright © (2012) by the International Astronautical Federation., SCOPUS: cp.p, info:eu-repo/semantics/published