MarcoPolo-R is ESA's mission concept for a sample return from a near-Earth asteroid. The spacecraft would rendezvous with a primitive near-Earth asteroid, scientifically characterize it at multiple scales, and return a sample to Earth. MarcoPolo-R will be ESA's first sample ever returned from a primitive asteroid, aimed at improving our understanding of the origin and evolution of the solar system, the Earth, and life itself. A sample return is important to help scientists investigate the volatile-rich (e.g., water) nature of primitive near-Earth asteroids, which may be important for future space resource utilization.
MarcoPolo-R will return a sample from a near-Earth asteroid. This mission aims to answer the following key science questions:
What were the processes occurring in the early solar system and accompanying planet formation?
What are the physical properties and evolution of the building blocks of terrestrial planets?
Do near-Earth asteroids of primitive classes contain pre-solar material yet unknown in meteoritic samples?
What are the nature and the origin of the organics in primitive asteroids, and how can they shed light on the origin of molecules necessary for life?
Why Study Asteroids?
Near-Earth asteroids and other small bodies are primitive leftover building blocks of the solar-system-formation process and offer clues to the chemical mixture from which the planets formed. In addition, current scenarios for the origin of life suggest that an external source may have delivered organic matter to the early Earth; it has been proposed that primitive bodies could have brought these complex organic molecules capable of triggering the prebiotic synthesis of biochemical compounds on the early Earth. Lastly, collisions of near-Earth asteroids with the Earth pose a finite hazard to life. For all of these reasons, the exploration of such objects is particularly compelling.
Scientists know that asteroids show great diversity in their compositions, densities, and other properties. Each asteroid has a unique story to tell, which helps us understand the overall history of the solar system. Sample return is crucial to understanding diversity: the story of the Moon has required samples returned via six NASA and three Soviet missions; similarly, our understanding of Mars has required a series of missions visiting different parts of the planet. Understanding primitive bodies such as asteroids also requires visits to and samples from several bodies.
NASA Support of MarcoPolo-R
NASA will launch the OSIRIS-REx sample return mission to the asteroid Bennu in coming years and is ready to support MarcoPolo-R's visit to asteroid 2008 EV5. The MarcoPolo-R target represents a different type of primitive target; evidence suggests that 2008 EV5 formed and evolved in a water- and organic-rich environment independent of Bennu, and thus adds important science context. The unique science value of 2008 EV5, and its complementarity to other asteroid targets, reinforces NASA interest in MarcoPolo-R through the provision of technologies and techniques developed for OSIRIS-REx. NASA's support of an ESA mission not only enhances the science return from MarcoPolo-R but also further advances NASA's science goals.
Beyond reasons of scientific excitement, NASA is also interested in asteroids because of the potential hazard they present to our biosphere via impacts. We have begun to consider how we might deflect a hypothetical incoming asteroid in order to prevent damaging impacts. Here too, the diversity of the asteroids is important because we do not yet know the range of properties we may find in typical asteroids. NASA's support of MarcoPolo-R will help return important information about 2008 EV5 that will be of critical utility in understanding how we might best deflect hazardous bodies.