Progress in a physical approach to contamination in Europe

Roussel, Jean; Vanhove, Emilie; Grosjean, Eudes; Faye, Delphine; Rioland, Guillaume; Rampini, Riccardo; Ergincan, O.

doi:10.1117/12.2320013

Cited by 3 publications

(5 citation statements)

References 9 publications

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“…Jean-François Roussel, 1 David Lansade, 2 Ludivine Leclerc 3 ONERA-DPHY, Université de Toulouse F-31055 Toulouse, France Carlos E. Soares, 4 John M. Alred, 5 Maxwell G. Martin, 6 Anthony T. Wong, 7 John R. Anderson 8 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91107, USA and Delphine Faye, 9 Guillaume Rioland 10 CNES -French Aerospace Agency, 18 Avenue Edouard Belin, F-31401, Toulouse, Cedex 9, France Prediction of contaminant levels is paramount to controlling and reducing their impact on space missions. In the recent years, it has become clear that a real breakthrough could only be achieved through a change of paradigm, namely by going beyond the classical characterization of total contaminant mass and rather characterizing the various emitted chemical species individually, both quantitatively and chemically.…”

Section: Film and Silicone Adhesive Utilizing Astm-e-1559 Mass Spectr...mentioning

confidence: 99%

“…However efficient as GC-MS species separation is, it cannot be implemented in situ and in real time. In this context, coupling of thermogravimetric analysis (TGA) with MS, even though it only implements a partial species separation, seems more promising and has been successfully used [2], [4]- [6]. Numerical processing of these rich MS data is just as challenging.…”

Section: Introductionmentioning

confidence: 99%

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Molecular Characterization of Polyimide Film and Silicone Adhesive Outgassing Using Mass Spectrometry

Roussel¹,

Lansade²,

Leclercq³

et al. 2023

Journal of Spacecraft and Rockets

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The prediction of contaminant levels is paramount to controlling and reducing their impact on space missions. In recent years, it has become clear that a real breakthrough could only be achieved through a change of paradigm, namely, by going beyond the classical characterization of total contaminant mass and instead characterizing the various emitted chemical species individually: both quantitatively and chemically. This paper first reviews the methodology proposed to achieve this objective and then its implementation on two examples of materials (Black Kapton® and NuSil CV4-2946) on the basis of existing ASTM-E-1559 outgassing data (Garrett, J. W., Glassford, P. M., and Steakley, J. M., “ASTM-E-1559 Method for Measuring Material Outgassing/Deposition Kinetics,” Journal of the IEST, Vol. 38, No. 1, 1995, pp. 19–28) including mass spectrometry (MS) data. We show that the thermogravimetric analysis performed on the contaminant deposits (heating at 1 K/min) allows a good enough time separation of chemical species to analyze and often identify them through their mass spectra. In turn, the knowledge of the fragments constituting their spectra allows an improved analysis of the MS data collected during the initial outgassing phase. The outgassing time profiles of each of these chemical species then tells a lot about their actual outgassing physical laws. On the two studied materials, outgassing physics were found to be consistent with Fickian or non-Fickian diffusion rather than with residence time desorption. After confirming these findings with more specific and more sensitive experiments, the door will be open to greatly improve assessments of the contaminant amounts and nature in flight through realistic multispecies physical models.

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Section: Film and Silicone Adhesive Utilizing Astm-e-1559 Mass Spectr...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Molecular Characterization of Polyimide Film and Silicone Adhesive Outgassing Using Mass Spectrometry

Roussel¹,

Lansade²,

Leclercq³

et al. 2023

Journal of Spacecraft and Rockets

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“…So far, contamination predictions rely on several contamination outgassing and reemission models themselves relying on different laws, sometimes IOP Publishing doi:10.1088/1757-899X/1287/1/012022 2 chosen somewhat arbitrarily: first order desorption, zero order evaporation, diffusion, bouncing or sticking on surfaces, etc. [2]- [5] Though models currently used to fit laboratory week-long contamination experiments and allowing long-term predictions could work well in the hypothetical case where only one chemical species would outgas from a source, their application to real-case materials does not provide satisfactory results. Indeed, it is fairly easy with current methods to fit any data obtained by increasing the number of "virtual species" used to model any of the phenomena already mentioned.…”

Section: Introductionmentioning

confidence: 99%

“…For the past 15 years, ONERA, with the help of its partners among which ESA and CNES play an important role, has been convinced that the only way to perform accurate long-term predictions of contamination phenomena is to decipher the data gathered as a total mass in lab experiments into a sum of physical laws for each constituent of the contamination deposit characterized individually [6]. To do so, a technique known as species separation and identification of contaminant species by thermogravimetric analysis coupled to mass spectrometry (TGA/MS) is being developed [7], [8], [9]. Another interesting approach consisted in attempting a species separation based on peaks seen on QCMs during TGAs, and attributing them to different (unidentified) species [10], [11].…”

Section: Introductionmentioning

confidence: 99%

“…The purpose of this study is to strengthen the TGA/MS-technique knowledge that has started to be gathered by ONERA and its partners in the last decade, then mainly on a structural epoxy adhesive, namely Scotchweld EC-2216 [5], [9], and refine the technique leading to the characterization of contaminants. In this context, species separation and identification by TGA/MS was now applied with success to another epoxy glue, Scotchweld EC-9323-2.…”

Section: Introductionmentioning

confidence: 99%

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Contamination Level Prediction: Progress in Species Separation by TGA/MS

Lansade

Roussel

Faye

et al. 2023

IOP Conf. Ser.: Mater. Sci. Eng.

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Molecular contamination can be detrimental to spacecraft life expectancy as it may induce changes to the properties of the surfaces on which it deposits. In order to control these potential issues, manufacturers need to assess in-flight contamination levels in the quite early design phases, possibly leading to design changes or extra material bake-out to fulfil requirements. The accuracy of model assessments may thus have direct impacts on missions and costs. Prediction of outgassing and deposition at mission timescale is done by extrapolating short-term on-ground experimental results, by fitting the latter with some empirical or physical laws. Common methods are the power law interpolation (in isothermal conditions) or the residence time approach (with thermally activated time constants), which leads to exponential decays in isothermal conditions. Although they allow fitting the measured outgassed flux over few-day-long experiments, their extrapolation to ten or fifteen-year-long missions is more challenging. Validating empirical laws might involve long-term empirical comparisons, while obviously the validation of physical models should start with checking their physics. In spite of many years trying, a basic difficulty was yet found to block significant progress on physical validation. As long as measurements are limited to the total mass on QCMs it looks possible to fit data as a sum of almost any law, such as residence time or diffusion models e.g. for outgassing. Following this observation, a conclusion was drawn that the only way to discriminate between two different physics was to characterize contamination at chemical species level. Such characterizations are a prerequisite to unravel the physics at play during several phenomena: outgassing, deposit films dynamics, photochemistry, environment/ATOX interactions, etc. This innovative approach, presented herein, aims at identifying outgassed contaminants by means of coupled thermogravimetric analysis and mass spectrometry. For this purpose, this paper reports the successful species separation and identification of contaminants outgassed from a material used in space applications: the epoxy adhesive Scotchweld EC-9323-2.

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