The in-situ investigation and sample analysis would allow scientists to improve our knowledge of the physical and chemical properties of a small Near-Earth Object (NEO) which is thought to have kept the original composition of the solar nebula in which planet formed.
Small bodies, as primitive leftover building blocks of the Solar System formation process, offer clues to the chemical mixture from which the planets formed some 4.6 billion years ago.
Current exobiological scenarios for the origin of life invoke an exogenous delivery of organic matter to the early Earth: it has been proposed that carbonaceous chondrite matter (in the form of planetesimals or dust) could have brought these complex organic molecules capable of triggering the pre-biotic synthesis of biochemical compounds on the early Earth.
Marco Polo was a proposed ESA-JAXA space mission aimed at visiting a small primitive asteroid and returning a sample to Earth for analysis in laboratories.
A baseline mission scenario to 1999 JU3 would have included a launch with a Soyuz-type launcher of a mother Spacescraft (MSC) possibly carrying a Lander, a sampling device, a re-entry capsule and scientific payloads.
The Lander would perform a soft landing, anchor to the asteroid surface, and make various in-situ measurements of surface/subsurface materials near the sampling site.
In February 2010, ESA announced that it has chosen the Euclid, Solar Orbiter, and PLATO missions to enter the definition phase, and Marco Polo was not selected by the SPC for further study.
[4] Since the return capsule of Hayabusa Mk2 will enter Earth's atmosphere at the velocity beyond 14 km/s, a technology demonstrator called DASH-II was proposed within the JAXA Space Exploration Center (JSPEC).
The estimated aerodynamic heat load on the capsule is extremely high (at least 20 MW/m2) even by selecting a shallow entry flight path angle.
The MSC scientific payloads have to include a high resolution imaging system, visible and infrared and mid spectrometers, a LIDAR, and a dust monitor.
These instruments will be operated during the approach, hovering and descent phases for science purpose, for landing site selection and for spacecraft safety during near-surface manoeuvres.