Investigation On Risk Assessment For Spacecraft In Meteoroid Environment

With the development of human space activities, many spacecrafts have been sent into the low earth orbital space. Most of the spacecrafts are suffering from the bad space environment, and the space debris, included meteoroid and orbital debris, imperiled the spacecrafts most. For these debris always moves with hypervelocity, once a spacecraft encountered them, it would leads to a damage to the craft. Especially to the manned spacecraft, this impact may imperil the life of astronaut. For these reasons, it is very important for spacecraft with long operation lifetime and high security requirement to take risk assessment of space debris impact. So far many countries are researching the technology of risk assessment of space debris impact, some of them already have a risk code, which can be used to value the risk assessment for the spacecraft in both meteoroid and orbital debris environment. The thesis presents a research on the risk assessment for the spacecraft in meteoroid environment and the shadowing effect which must be considered in the risk assessment.First, after careful research on the meteoroid model, method on directional discretization has been found. A standard model of the meteoroid environment is built with the design concept of the orbital debris model. And the program module which diverts the result of meteoroid environment model to the standard model is compiled. The probability of impact or failure is calculated by Finite Element Analysis Method and the arithmetic flow of spacecraft risk assessment in the meteoroid environment is designed.Second, both the earth shadowing effect and the spacecraft shadowing effect are discussed thoroughly. Using the method of eliminating hiding surface in Computer Graphics, program module of processing shadowing effect is designed which ensures the precision of the risk assessment code.Finally, a risk assessment code, based on the meteoroid environment model SSP30425, for spacecraft in the meteoroid environment is compiled. And it is proved to be available after assessing the risk by meteoroid impact for three generic spacecraft geometries, which are offered by IADC in order to validating different codes, and comparing the result with other foreign codes.