Analysis Of Space Capsule Water And Landing Impact Compatibility

Capsule returning and landing process is the key point of the manned spaceactivity, which has a great effect on the whole manned space mission. When thecapsule returns, because of the outside interference and system failure, Underextraordinary circumstances, the capsule may deviate from the predeterminedorbit and the recovery mode of the capsule may change either, for example fromlanding impact to water impact. Hence the analysis of water and landing impactresponse characteristics and influencing factors as well as to research the impactresponsing compatibility between the two is of great importance.The FEM method has be used in water and landing impact simulating andresearching of spacecraft capsule in China for many years, but the compatibilityresults between the water and landing impact haven’t been publicly seen indomestic literatures. In this paper, Based on an existing landing impact FEMmodel for Shenzhou spaceship capsule, the test design can be used to analyse thesignificance of landing impact factors, result indicated that for landing impact,vertical velocity of landing is the most significant factors for maximum impactacceleration. For a fixed vertical velocity, the horizontal velocity, the pitch angleand the heeling angle are significant, while the horizontal velocity is moresignificant than the other two. Meanwhile, by analysing single-factor andtwo-factor landing impact characteristics on vertical and horizontal velocity, theresponding surface and the fitting surface can be obtained. The results abovealong with the results of water impact responsing factors researched by ZhangXuhuai et al. can be the analytical reference of water and landing impactcompatibility.The compatibilities between water and landing impact under differentconditions including the same condition, equivalent conditions and the samedegree of injury risk were analysed in this paper as well. The results show thatunder the same condition (with the same vertical velocity and horizontalvelocity), the landing impact responding surface was on top of the water impact responding surface. Landing impact generates larger accelerations, water impactis more conducive to occupant protection. While in equivalent conditions, a crossexists between water and landing impact surface. The landing impact surface wasdivided into upper and lower parts by the water impact surface. By projecting theintersection of water and landing impact surface on ‘equivalent vertical velocity-horizontal velocity’ plane, two areas A and B can be found on the plane. In Aarea, water impact generates larger accelerations. In B area, landing impactgenerates larger accelerations. Under the same degree of injury risk, theconstraint curves of water impact were on top of those of landing impact.Conditions that meet the requirements are broader in water impact.Besides, combined with the compatibility of water and landing impact, theconstraint curve of water and landing impact under different conditions can beobtained and painted. Furthermore, by preliminarily studying the reference ofselection of recovery mode and capsule landing posture in returning phase, arelated process of deciding recovery mode was provided in this paper. We alsoprovided a method of accessing jury risk in capsule recovery.