Ariel is the fourth medium-sized mission (M4) selected under ESA's Cosmic Vision 2015-2025 programme, and is scheduled for launch in 2029. The thermal design is based on a passive and active cooling approach. To take advantage of the thermal conditions of the L2 orbit, a combination of a V-groove shield and a radiator coupled to deep space will be used to cool the telescope and optical bench to stable temperatures in the 50-60 K range. As one instrument requires to operate below 42 K, an active cooling system based on a Neon Joule-Thomson will be used. As the four mirrors and detectors are critical units, the success of the mission depends on their proper functioning. Therefore, two possible in-flight decontamination scenarios have been considered in case of need to remove thin ice films deposited on the critical optical surfaces. The first scenario considered is during the flight to L2 and the second is in case, once at operational temperature, any anomaly is observed in the observations. This paper presents preliminary results for the design of the Ariel decontamination lines. In addition, due to the nature of the simulations required (transients of many days), the effect of the time step on the duty cycle of the heaters has been analysed, so that a trade-off between computational cost and accuracy of the results can be concluded.
FERNANDEZ-SOLER et al. (Sun,) studied this question.