A CubeSAT payload for in-situ monitoring of pentacene degradation due to atomic oxygen etching in LEO

Gorreta, Sergi; Pons-Nin, Joan; López, Gabriel Montoro; Figueras, E.; Jove-Casulleras, R.; Araguz, Carles; Via, Pol; Camps, Adriano; Domínguez-Pumar, Manuel

doi:10.1016/j.actaastro.2016.06.028

Cited by 12 publications

(6 citation statements)

References 20 publications

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“…The recursive method has the same convergence properties as minimizing (24), namely converge to a local minimum of J est or the boundary of D [38, theorem 2], resulting in the best approximation of the true system available in M.…”

Section: Estimating the Frequency Shiftsmentioning

confidence: 99%

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Model-based resonance tracking of linear systems

Vasileiou

2018

Preprint

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This paper develops a recursive algorithm for tracking resonance frequency shifts of linear timevarying systems corrupted by additive white Gaussian noises, in real time. So far, automatic resonance tracking is limited to non-model-based designs that rely solely on the phase difference between a selected input and output of the system. Instead, we propose a transformation of the system into a complex-valued representation, which allows to abstract the resonance shifts as an exogenous disturbance acting on the excitation frequency, perturbing it from the natural frequency of the plant. The resonance tracking problem is then split in two tasks; identifying the frequency disturbance and solving an optimization problem to determine the excitation frequency. The design of the resonance tracker is therefore simplified, due to the application of well-established techniques. We discuss the stability of the proposed scheme, even in cases that seriously challenge the current phasebased approaches, like non-monotonic phase differences and multiple-input multiple-output systems. Numerical simulations further demonstrate the performance of the resonance tracking scheme.Keywords resonance • frequency tracking • time-varying systems • complex variables • closed-loop identification.

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Section: Estimating the Frequency Shiftsmentioning

confidence: 99%

“…Regardless the application, the phase locked loop (PLL) [21,7] and the self-sustained oscillation (SSO) schemes [23,24] are the norm for resonance tracking. Briefly, both techniques achieves tracking of the resonance frequency by keeping a constant phase difference between the input and the output of the system.…”

Section: Introductionmentioning

confidence: 99%

Model-based resonance tracking of linear systems

Vasileiou

2018

Preprint

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“…; however, it can be damaged so easily in the AO environment [6,7]. Over the years, quantities of AO environment tests have been conducted to aggravate polyimide's degradation so as to extend the spacecraft lifespan, either using in situ flying tests [8][9][10] or in ground-based test facilities [11][12][13]. Nevertheless, the dynamic procedure of the AO interaction and the atomical bonding and breaking could never be observed using those two methods.…”

Section: Introductionmentioning

confidence: 99%

Study on the Effects and Mechanism of Temperature and AO Flux Density in the AO Interaction with Upilex-S Using the ReaxFF Method

Qiao,

Jiang,

Zhai

et al. 2023

Coatings

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Atomic oxygen (AO), which is one of the most predominant and conspicuous space environmental factors in the low earth orbit, leads to severe deterioration of polymeric materials in spacecraft. The AO flux density and ambient temperature vary while a craft orbits in space; thus, it is necessary to pay close attention to the flux density and temperature effects on the mechanism of the AO interaction with materials. In past years, polyimide has been widely used on spacecraft due to its excellent performance—that is the reason why we chose Upilex-S as the object for study. It was analyzed using the ReaxFF reactive force field molecular dynamics simulation, respectively from the aspect of impact-induced temperature variation, mass loss, reaction product and erosion yield. The results show that dense AO deposition on the surface impedes further erosion at low temperatures, and the AO interaction with Upilex-S is exacerbated as the ambient temperature increases. However, the accelerating rate is inversely proportional to the ambient temperature, which means the higher the ambient temperature is, the slower it increases. On the other hand, the interaction rate of AO induced to Upilex-S is aggravated as the flux density increases at the lower stage, while the interaction rate begins to drop as the flux density increases at the higher level. The AO erosion effect is a complicated process rather than a simple summation of single atomic oxygen interactions. Our study could be used as a technical reference for the wide usage of Upilex-S on spacecraft.

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“…Toward this end, we became interested in the heterogeneous oxidation of PAHs bound to the surface of highly oriented pyrolytic graphite (HOPG) using near-thermal energy atomic oxygen. While there are studies regarding the reaction between PAHs and atomic oxygen, − especially with astrochemical interest, these typically focused on etching processes and not on the direct molecular oxidation products. We have recently probed the oxidation of thin coronene (C 24 H 12 ) films using mass-resolved temperature-programmed desorption (TPD) to characterize the volatile oxidic products generated under these conditions. , Interestingly, we observed significant amounts of intactly desorbing coronene oxides.…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of Direct and Graphite-Mediated Oxidation of Large PAHs

et al. 2021

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We have used a surface-science-based, ion-beam-soft-landing approach to study the heterogeneous oxidation of a series of large polycyclic aromatic hydrocarbons (PAHs) deposited onto highly oriented pyrolytic graphite (HOPG). The reactivities of well-defined thin films of hexabenzocoronene (C42H18), pentacene (C22H14), fullerene precursor (C60H30), and rubrene (C42H28) with effusive beams of oxygen atoms were compared to the reaction outcome upon depositing a monolayer of the same PAHs onto a preoxidized graphite surface. In both cases, sublimable oxidized derivatives of PAHs were observed using mass-resolved temperature-programmed desorption (with compositions assigned using oxygen isotope labeling where necessary). For all PAHs investigated, the on-top oxidation of multilayers leads to epoxides. By contrast, the products of the oxidation of (sub)monolayers are seen to depend on the molecular structure of the PAH. While the flatly adsorbing planar PAHs react to form lactones and quinones, the highly nonplanar rubrene does not show analogous surface-mediated chemistry, instead forming epoxides exclusively. These observations when taken together with our previous study of coronene oxidation are of potential interest for sp2-nanocarbon-based oxidation catalysis. Furthermore, we have demonstrated a ultra high vacuum (UHV)-based route to sublimable oxides ranging in size up to C60H30O5, which may be useful for nanotechnological applications.

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A CubeSAT payload for in-situ monitoring of pentacene degradation due to atomic oxygen etching in LEO

Cited by 12 publications

References 20 publications

Model-based resonance tracking of linear systems

Model-based resonance tracking of linear systems

Study on the Effects and Mechanism of Temperature and AO Flux Density in the AO Interaction with Upilex-S Using the ReaxFF Method

Comparative Study of Direct and Graphite-Mediated Oxidation of Large PAHs

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