Marco Polo (spacecraft)

Marco Polo was a spacecraft concept developed between 2005 and 2015 that aimed to collect a sample from a near-Earth asteroid and bring it back to Earth for lab analysis. The European Space Agency first proposed it with Japan’s JAXA, which called the idea Hayabusa Mk2. Despite support from over 400 scientists worldwide, the concept was turned down four times between 2007 and 2015 for ESA’s Cosmic Vision medium-class mission slots (M1 through M4).

The mission’s main goal was to return pristine material from a near-Earth object for study that robotic spacecraft alone cannot do. This would help scientists understand the physical and chemical makeup of small bodies, which are thought to preserve the original composition of the solar nebula from which planets formed. Such data could refine models of planet formation and shed light on how organic compounds—possibly key to life’s origins—might have been delivered to early Earth. It would also provide information on an asteroid’s physical structure, aiding in the design of strategies to deflect any that threaten Earth.

Marco Polo would have examined a target’s surface morphology, environment (dust, gravity), mass, volume, density, mineralogy, thermophysical properties, elemental composition, internal structure, topography, volatile abundance, and organic compounds. Additional objectives included identifying major events in the target’s history (like heating or water alteration), searching for pre-solar material not found in meteorites, and investigating how minor body impacts contributed to life’s origin and evolution on Earth.

After its first two rejections for the M1 and M2 competitions (planned for 2018 and 2020 launches), the mission was renamed MarcoPolo-R and submitted for M3, losing in 2014. It was then renamed MarcoPolo-2D for the M4 opportunity but was rejected at the first stage in March 2015. A baseline scenario for asteroid 162173 Ryugu involved a Soyuz launch of a mother spacecraft, possibly carrying a lander, sampling device, re-entry capsule, and scientific instruments. The lander would touch down, anchor, and take in-situ measurements. Samples would be collected using one or more techniques. After sampling, the mother spacecraft would return to Earth and release a capsule for high-speed re-entry. Following quarantine and sterilization, the sample would be opened in a dedicated facility for initial characterization before distribution to scientists.

Proposed targets included C-type asteroids 162173 Ryugu and (65679) 1989 UQ, primitive D-type and T-type asteroids, dormant comet 4015 Wilson–Harrington, and a primitive C-type binary asteroid. The payload would have featured a high-resolution imaging system, visible and infrared spectrometers, a LIDAR, and a dust monitor, used during approach, hovering, and descent for science and safety. The lander would carry its own instruments for in-situ measurements.