Study and ground simulations of outgassing and hypervelocity impacts on carbon-based materials for space applications

摘要

Recently, the focus of Space Research has been set both on scientific and commercial fields. When planning a mission in space, it is necessary take into account the environment in which the instrumentations and the satellite that carries them will go to work. About 25% of operating anomalies are in fact due to the space environment that affects the control and management systems of the spacecraft and of the instrument. So it is mandatory to guarantee the compliance with the low earth orbit (LEO) space environment that degrades the performances and functionality of materials with phenomena such as atomic oxygen (AO), ultraviolet (UV) radiation, plasma, micrometeoroids and orbital debris (MMOD), as well as extreme thermal states given by orbital temperature cycles. In this frame the study of Outgassing properties and the hypervelocity impact resistance of space materials and in particular of Carbon based materials is of primary importance. A material with poor outgassing properties will degas volatile particles of itself and humidity with critical effects on electronic and optical devices. The resistance to high vacuum will assure the durability and the reliability of materials and structures. Very important is also the ability of a material or a structure to withstand impacts of MMOD. In this paper Outgassing and impact tests have been carried out on samples obtained from C/C prototypes for employment in re-entry systems and on samples of Carbon Fiber Reinforced Polymer (CFRP). The outgassing tests have been performed both on “naked” and coated samples per C/C kind and on CFRP. An Advanced Linear Electromagnetic Accelerator (ALEA), named railgun, has been developed in order to perform high energy impact test. The experimental results of impact test showed a damage limited to the Carbon based materials shell and could be adopted as solution to guarantee a safe mission and furthermore also that the railgun is suitable to perform impact testing of materials in the space debris energy range; at last, outgassing tests results show a complete compatibility of the materials under investigation with the standard.