'Peaks in space' - crystallography in planetary science: past impacts and future opportunities

Crystallography has done much to underpin and enhance our understanding of our planetary neighbours. From analysis of the samples plucked from space by audacious sample-return missions, to the detailed study of meteorites that have landed on our planet's surface; investigations of the crystal structures, the growth of components and the physical properties of these precious samples has been key to teasing out the story of these fragments and their parent bodies. To prove that there are no limits to the ends that a crystallographer will take to collect planetary data, there is now one diffractometer working another planet, Mars. Not to be daunted by the lack of samples from beyond the terrestrial planets, crystallography has also been at the forefront of in situ experiments that recreate the extremes of planetary environments. This review will capture how crystallography has been used to all of these ends and reveal a number of opportunities for future application of the technique.