Application of Adsorbents to Space Use for Prevention of Molecular Contamination

Abstract

The issues of degradation of data of on-board sensors, deterioration of thermal control function, and so on are known to occur by depositing molecular contaminants on the surface of spacecraft. To solve these issues, the application of adsorbent is proposed in the present research. Pure porous material (MCM-41) and 4 types of adsorbents consisting of MCM-41 as the base material with different binders (methyl cellulose 4000 or water glass) were prepared. Some samples were heat-treated at 150°C for 3 hours. To clarify their adsorption characteristics and apply them to space use, they were evaluated by scanning electron microscopy (SEM), gas adsorption method, outgassing test, adsorption test toward hexamethyl cyclotrisiloxane (D3) method, and thermogravimetry analysis combined with in situ evolved gas analysis by mass spectrometry (TG-GC-MS). These analyzes revealed that all of the adsorbents have a high adsorption capability to D3. In particular, the two types of the adsorbents with MC4000 binder showed an improved adsorption capacity of D3. The D3 desorption process started at a temperature of around 200 °C for the 4 types of manufactured adsorbents, while the pure MCM-41 powder desorbed D3 completely below 200 °C. The forming process of the adsorbents, such as mixing binder components and heat treatment conditions, would influence the desorption process of D3.