An X-ray spectrometer for Marco Polo

Marco Polo is a joint European/Japanese mission proposed for the European Space Agency's 'Cosmic Vision' programme for launch between 2015 and 2025. The primary objective is to return unaltered materials from a primitive Near Earth Object (NEO) to the Earth. NEOs are part of the small body population that represents the primitive leftover building blocks (embryos) of the Solar System formation process. They offer important clues to the chemical mixture from which the planets formed about 4.6 billion years ago and carry records both of the Solar System's birth/early phases and of the geological evolution of small bodies. This mission will provide the first opportunity for detailed laboratory study of the most primitive materials that formed the terrestrial planets and advance our understanding of some of the fundamental issues in the origin and early evolution of the Solar System and possibly life itself. Marco Polo aims to: * Determine the physical and chemical properties of the target body, which are representative of the planetesimals (planetary building blocks) present in the cloud of gas and dust that surrounded the developing Sun, * Identify the major events which influenced the history of the target NEO, * Determine the elemental and mineralogical properties of the NEO and place them in the geological context of the surface. * Search for new types of interstellar grains that pre-date the Solar System and provide clues to their origin in stars and their evolution in inter-stellar clouds. * Investigate the nature and origin of organic compounds on the target body and identify those which may reveal the origin of pre-biotic molecules on the Earth. Although we already have samples of asteroids in our terrestrial meteorite collections which have provided important scientific clues to the objectives listed above they have suffered terrestrial contamination and weathering, and the most primitive material does not survive the process of entry into the Earth's atmosphere. A sample return mission to a primitive asteroid will return new types of material for laboratory study, collected and stored under optimum conditions, linked to a specific source body with geological context. Terrestrial laboratories provide high precision & accuracy, allow complex sample selection and preparation, the ability to analyse the same sample using many techniques and retention of material for future advancements, none of which are possible with experiments at the target. However the spacecraft will provide physical and mineralogical measurements over the whole NEO to provide geological context for the returned samples and allow us to study large scale processes, such as the history of impacts and geological disruption. This proposal is for funds to support preparatory activities in the UK to maximise the science return and ensure good UK participation for scientists and industry in the Marco Polo Mission if it is selected. This proposal is a revised version requesting funds awarded by PPRP.