Simulations of earth's local particulate environment.

Since the dawn of the space age the near earth environment has been becoming increasingly more cluttered with man made products. In recent years there has been a growing fear that the size of this population is approaching a critical threshold. If the population should pass this threshold there would follow a catastrophic series of collision related breakups resulting in a space environment too 'dirty ’ to make further satellite launches feasible. The situation is further aggravated by the existence of natural cosmic dust passing through near Earth space.

The broad aim of the project was to help achieve a better understanding of the near Earth cosmic dust and space debris environment. Specifically the aim was to test existing theories about the dust and debris populations by the use of modelling, experiments and of actual data taken from space exposed materials, from the Long Duration Exposure Facility (LDEF).

Two independent computer models were created. The first model simulates impacts on LDEF from cosmic dust particles. The second model simulates impacts on LDEF from space debris.

The models allow the researcher to vary certain parameters about debris and dust populations. The models will then predict, from the researcher's defined parameters, the quantity and distribution of impacts expected on LDEF. These predictions can then be compared with the data gathered from microscopic examination of LDEF materials.

A number of possible scenarios were investigated in this manner and their strengths and weaknesses assessed in terms of how well they satisfied the LDEF data.

In addition an experimental program using a light gas gun and an electrostatic accelerator to produce hypervelocity impact craters was initiated. Ways of attaining more information about individual impact events by study of the impact crater morphology were investigated.