Comets are among the most primitive bodies in the Solar System, and as such are believed to contain material that is relatively unchanged since the formation of the Sun and planets. They also have the advantage of making periodic passages through the inner Solar System, where they can be intercepted by spacecraft. The Rosetta mission has, for the first time ever, accomplished a rendezvous with a comet and deployed a lander to its surface. Rosetta will accompany the comet until at least the end of 2015, presenting an exceptional opportunity to study the evolution of a comet and its activity, revolutionizing our understanding of comets.
On-board Rosetta is a unique instrument called MIDAS which uses Atomic Force Microscopy (AFM) to unlock the secrets of cometary dust at the nanometre scale. MIDAS will collect the smallest cometary dust grains in situ and analyse them with respect to their size, shape, roughness, magnetic properties and possibly mineralogy.
This project addresses a range of questions in cometary science from a new perspective by using the data delivered by MIDAS. The instrument acquires 3D images with nanometre resolution of the most pristine cometary dust particles, from which statistical properties can be derived, including size, shape, porosity and the fraction that are aggregates versus compact particles. The morphology of the dust grains will be investigated with unprecedented resolution, giving the possibility to determine the building blocks of cometary dust. Magnetic Force Microscopy (MFM) data will be used to identify grains with magnetic minerals and could even constrain the strength of magnetic fields in the early Solar System. MIDAS data also address the evolution of dust in the coma, in particular the size distribution of the smallest particles and the fragmentation mechanisms of cometary dust. In this project novel AFM data analysis techniques are developed to fully exploit the data from this instrument.
In addition to studying the existing data set, the timeframe of this proposal and the fact that the project leader is the Principal Investigator (PI) of MIDAS allow additional dust collection campaigns and new AFM/MFM analyses. This project supports novel science as part of one of the most exciting planetary science missions of our time.