Modelling of spacecraft thermal control coatings degradation

Аuthors

Kudriavtseva N. S.

Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia

e-mail: nkudr@mai.ru

Abstract

Thermal control coatings provide the required thermal radiation characteristics of the surfaces: the solar absorptance and the thermal emissivity coefficient. Thermal radiation characteristics must meet the required level at the beginning of operation and maintain the specified level until the end of the service life of the spacecraft.

During long-term space flights, degradation of the solar absorptance is observed, which causes a gradual increase in temperature and can lead to premature termination of the spacecraft flight. The influence of space flight factors on thermal control coatings is largely random and depends on the region of space, the orbit and the orientation of the spacecraft in orbit.

The paper presents a stochastic mathematical model of the degradation process of thermal control coatings based on a random Wiener process with a time function transformation. The model takes into account the random and complex nature of the impact of space flight factors on the thermal control coa-tings of the spacecraft surfaces.

Traditionally, during the design process, the reliability of a spacecraft radiator is assessed based on the probability of sudden failures. The process of degradation of the thermal control coatings of the radiating surface during flight is the cause of gradual failures of the radiator, therefore, its normal operation continues until the first of the sudden or gradual failures. Based on the proposed method of modeling the degree of degradation of the radiating surface, an analytical dependence was obtained for assessing the parametric reliability of the radiator.

As an example, a modeling of degradation processes of three types of thermal control coatings related to the class of solar reflectors was carried out for radiator coating based on the results of experimental studies conducted during a five-year flight of the “Yamal-200” spacecraft in geostationary orbit. The high accuracy of modeling and forecasting the degradation of thermal control coatings for the next five years of flight has been confirmed.

An analytical dependence was obtained and a numerical assessment of the parametric reliability of radiators with a radiating surface covered with three types of thermal control coatings for long-term flights in geostationary orbit was carried out.

Keywords:

thermal control coatings degradation, random Wiener process, parametric reliability, radiator, spacecraft

References

1. ISO 17851. Space systems – Space environment simulation for material tests – General principles and criteria. ISO; 2016. 24 p.

2. Sharma AK, Sridhara N. Degradation of thermal control materials under a simulated radiative space environment. Advances in Space Research. 2012;(50):1411–1424.

3. Liu T, Sun Q, Meng J et al. Degradation modelling of satellite thermal control coatings in a low earth orbit environment. Solar Energy. 2016;(139):467–474.

4. Gorodetskii AA, Kovtun VS, Frolov IV. Results of a space experiment to study the characteristics of thermoregulating coatings in geostationary orbit. Izvestiya RAN. Energetika. 2016;(3):93–101. (In Russ.).

5. Wang X, Balakrishnan N, Guo B. Residual life estimation based on a generalized Wiener degradation process. Reliability Engineering and System Safety. 2014;(124):13–23.

6. Basov AA, Prokhorov YuM, Surguchev OV. Heat pipe radiators in spacecraft thermal control systems. Izvestiya RAN. Energetika. 2011;(3):37–41. (In Russ.).

7. Malozemov VV, Kudriavtseva NS, Alekseev VA. Joint optimization of the thermal control system and cooled instruments characteristics. SAE Paper № 941376. 24th SAE International Conference (20–23 June 1994. Germany. 10 p.).

8. Belyavskii AE, Kudryavtseva NS, Sorokin AE. Hybrid radiator for spacecraft thermal control systems. Russian Engineering Research. 2022;42(1):57–59.

9. Gasnikov AV. (ed.). Lectures on random processes. Moscow. MFTI. 2019. 285 p.

10. Whitmore GA, Schenkelberg F. Modelling accelerated degradation data using Wiener diffusion with a time scale transformation. Lifetime Data Analysis. 1997;(3): 27–45.

11. Shiryaev AN. On martingale methods in problems of crossing boundaries by Brownian motion. Sovremennye problemy matematiki. 2007;(8):3–78. (In Russ.).

12. Balka J, Desmond AF, McNicholas PD. Review and implementation of cure models based on first hitting times for Wiener process. Lifetime Data Analysis. 2009;(15): 147–176.

13. Kobzar' AI. Applied Mathematical Statistics. For Engineers and Scientists. Мoscow: FIZMATLIT; 2012. 816 p. (In Russ.).

14. Gorodetskii AA, Sokolova SP, Kovtun VS et al. Thermo-optical characteristics of the thermal control coatings of the Yamal-200 spacecraft. Izvestiya RAN. Energetika. 2011;(3):23–36. (In Russ.).