&lt;title&gt;Contamination observed on the Passive Optical Sample Assembly-I (POSA-I) experiment&lt;/title&gt;

Zwiener, James M.; Kamenetzky, Rachel R.; Vaughn, Jason A.; Finckenor, Miria M.

doi:10.1117/12.328492

Cited by 5 publications

(3 citation statements)

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“…Deposits of molecular contaminants induced by outgassing from spacecraft are known to degrade the performance of optical components, the thermo-optical properties of thermal control surfaces and the power output generated by a solar array 1,2 . Recently, the influence of contamination on spacecraft has been relatively increasing, due to the extended life of spacecraft and improved performance of optical components, etc.…”

Section: Introductionmentioning

confidence: 99%

Experimental measurement of the reflection behavior of contaminant molecules

et al. 2014

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JAXA is developing a contamination analysis tool "J-SPICE" (Japanese Spacecraft Induced Contamination analysis software). Generally speaking, contamination analysis tools predict based on various input data and mathematical models of contaminant behavior, which means prediction accuracy depends on the validity of mathematical models as well as of input data. We investigated the validity of a diffuse reflection model applied in J-SPICE by comparing the reflection flux of contaminant molecules measured by the ground experiment and the analytical result of the J-SPICE. The result showed that the diffuse reflection model of J-SPICE reasonably explains molecule distribution reflected by a flat surface.

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Section: Introductionmentioning

confidence: 99%

Experimental measurement of the reflection behavior of contaminant molecules

et al. 2014

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“…Molecular contamination by outgassing, released from a spacecraft, can degrade the performance of optical components, the thermo-optical properties of thermal control surfaces, and power output generated by a solar array [1,2] . To restore performance, one typical method involves eliminating contamination from the surface, for which thermal heating and bakeout is commonly used.…”

Section: Introductionmentioning

confidence: 99%

Optical and re-emission behavior of silicone contaminants affected by UV irradiation with different wavelength ranges

et al. 2014

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Molecular contamination by outgassing can degrade the performance of optical components. In orbit, spacecraft are exposed to various environments. UV is one of the most critical. It may also have the potential to cut the chains of organic molecules in contaminants due to its high energy, degrading optical properties and even re-emission behavior. In the present study, using two kinds of UV sources with different wavelength ranges, we compare the effect of UV lights irradiated on an optical surface with silicone contaminants. The irradiated samples were evaluated in terms of their optical properties and re-emission behavior, i.e. transmittance, and thermal desorption.

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“…Modeling the material's thermo-optical properties, absorptance (α) and emittance (ε), is complex due to these effects. Ultraviolet (UV) darkening or photochemical darkening of thermal control materials and that of contaminant layers has been documented in numerous on-orbit experiments [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] and under simulated conditions [18][19][20][21][22][23][24][25] . The collection of data suggests that ceramic (inorganic)-based coatings/paints (Z-93, AZ93, YB-71) that have not been heavily contaminated have performed well in the space and simulated environment.…”

Section: Introductionmentioning

confidence: 99%

Characterizing the optical performance of AZ93 with a fluoropolymer overcoat under ultraviolet exposure

Huang

Schmidl

Soares

2008

Optical System Contamination: Effects, Measurements, and Control 2008

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AZ93 with a fluoropolymer overcoat is an option to simplify ground handling of space hardware. The overcoat applied on some on-orbit International Space Station (ISS) hardware provides contamination protection for optically sensitive ceramic thermal control coatings. However, if the fluoropolymer is not eroded on-orbit by atomic oxygen (AO), then it will darken. This will increase the solar absorptance resulting in possible thermal performance degradation. If the fluoropolymer overcoat was not present, optical performance would be significantly improved. To characterize the optical performance of the AZ93 with the fluoropolymer overcoat for modeling the UV degradation, laboratory testing of the coating was performed at Marshall Space Flight Center (MSFC). Sample coupons prepared by AZ Technology were exposed under vacuum to ultraviolet radiation. At periodic intervals, the samples were removed from the testing chamber to acquire images and to measure the solar absorptance. The images showed visible differences between AZ93 with the overcoat and without the overcoat as vacuum ultraviolet (VUV) exposure increased. Darkening is more pronounced in the samples with the fluoropolymer overcoat. This was also evident in the solar absorptance measurements. Optical properties of AZ93 with the fluoropolymer overcoat significantly degraded in comparison to those without the overcoat. A short period of little change followed by an exponential rise in solar absorptance was observed. The optical degradation of the fluoropolymer overcoat is described in terms of surface reaction chemistry and kinetics and is found to follow a pseudo first order reaction rate.

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<title>Contamination observed on the Passive Optical Sample Assembly-I (POSA-I) experiment</title>

Cited by 5 publications

References 0 publications

Experimental measurement of the reflection behavior of contaminant molecules

Experimental measurement of the reflection behavior of contaminant molecules

Optical and re-emission behavior of silicone contaminants affected by UV irradiation with different wavelength ranges

Characterizing the optical performance of AZ93 with a fluoropolymer overcoat under ultraviolet exposure

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