Space vehicle propulsion systems - Environmental hazards of low Earth orbit-lunar domain

Abstract

Introduction T HE methodology used for this investigation involved an examination, enumeration, and assessment of the open literature for detailed descriptions of the hazards to be discussed. Given this body of information, the potential of these hazards for degradation, disruption, or possible termination of performance of LOX-LH2 as well as other rocket engines, was considered. The mode of study was that of a selective literature search, in which candidate documents were selected on a basis of being current, as well as giving adequate quantitative detail. The hazards were then classified as to pervasiveness, abruptness, the capability of producing long-term hardware degradation and deterioration. They were then considered in relation to their specific influence in various mission modes in geolunar space. The overview of results and conclusions that follow came from approximately 350 citations and 200 extended documents. In view of time constraints, these numbers do not fully represent the total wealth of applicable and potentially useful literature on this subject. Table 1 summarizes the objective and findings of this study. We now consider the relevant space hazards and locales. For illustrative purposes, Table 2 enumerates these hazards in conjunction with the regions in geolunar space and their relative importance. Given the four dominant hazards—radiation, meteoroids, monatomic oxygen, and thermal gradient and thermal shock— Table 3 displays the space-hazard descriptions and anticipated deleterious effects. With the condensed information contained in Tables 1-3, we now present a detailed discussion of these hazards.