Evolution of solar system materials and bodies under hypervelocity impact

The work uses hypervelocity impacts (crudely impacts at speeds above 1 km/s) to probe a series of phenomena relevant to planetary science, We will look at the question of whether the shocks involved in hypervelocity impacts onto targets of mixtures of diferent ices and chemicals, can make amino acids and other complex organic molecules which are the ingredients of life. If they can, this may be a means for producing large amounts of these key molecules in space on icy bodies (such as comet nuclei or icy satellties of the outer planets). We will also investigate if ices which are doped with such compounds can successfuly deliver the compounds to targets during hypervelocity impacts. This could be a route for these compounds to arrive on an early Earth for example. We will explore this via both laboratory experiments and computer simulations. Regarding cratering process, we will start with impact cratering in hot rocks, typical of the surfaces of Venus and Mercury, where we have data from space missions, showing the presence of impact craters. That the properties of rocks change with temperature is well know, but not widely considered in impact cratering. We explore this using heated targets in our own gun and then trying to model the results using computer programmes, testing the validity of the models in the codes. We will also look at cratering in ices which have sand mixed into them. This is realistic of some types of icy body in the Solar System which are not pure water ice, but can have different amounts of silicates mixed into them. Again we will back up the experimental work (from our gun) with computer based modelling. As well as this, we will directly study cometary and interstellar dust by working on data analysis for the NASA Stardust mission, which in 2006 returned samples of these dusts from space to the Earth. We have a history of succesful involvement in studying these samples and will continue to do so. We not only study them in our laboratory, but also create analogue samples using our gun to understand any modification the real samples may have undergone when captured in space by the NASA Stardust spacecraft in hypervelocity impacts. As with all our proposed work, we will back the impact experiments with computer modelling, to more fully understand what is occurring. Finally we will also study some of the underlying physics in hypervelocity impacts, by studying impacts of small particles onto targets. When these projectiles are smaller than 10 millionths of a metre in size, the size of the resulting impact craters are a particularly sensitive test of our ability to correctly model high strain rate impact processes. We will carry out shots of various types of materials using our own gun and compare to what modelling predicts. In all our work, the combination of experimental work and computer modelling will provide a powerful tool for studying these impact processes. The results and insights gained will greatly aid our understanding of a wide range of phenomena of fundamental importance in the Solar System.