2D Science

The MarcoPolo-2D mission to study the D-type Near Earth Asteroid 2001 SG286 and return a sample for detailed laboratory investigation.  D-types are the most abundant asteroids beyond the outer edge of the main belt, in particular concentrated in the Trojan population located in the L4 and L5 Jupiter-Sun Lagrangian points. The D-type asteroids contain abundant organics and volatiles, and are widely believed to be the most primitive “rocky” material present in the solar system. They appear to have been formed in a region of the protoplanetary disk rich in frozen volatiles, possibly as far as the Kuiper Belt, and have been subsequently captured in their present locations following the migration of the giant planets.  Orbital perturbations provide a steady supply of D-types into the inner solar system near Earth asteroid (NEA) population that spacecraft can readily access.  From the orbital observations, in situ lander measurements and detailed laboratory analyses of the returned samples the mission seeks to answer the following fundamental questions :

1. What was the astrophysical setting of the birth of the solar system?
2. What is the origin of material in the early Solar System and how did it evolve?
3. What is the origin of water and the atmophile elements on Earth and other terrestrial planets?
4. What is the nature and origin of organic compounds in the early solar system and their involvement in the origin of life on Earth?
5. What is the nature of D-type asteroids and how do they relate to other classes of asteroids and to cometary bodies?

Within each top level question there are a series of more specific goals.

Answers to these fundamental questions require measurements with exceptionally high precision and sensitivity. Such measurements cannot be performed by a robotic spacecraft and therefore require a sample returned to terrestrial laboratories where instrumentation is unconstrained by mass, power, stability etc.  In order to understand the sample results detailed in situ characterisation of the body from orbital and lander measurements is required to provide geological context to the collected samples. Some measurements relating to the physical properties and interior structure can only be performed in situ by spacecraft.

MarcoPolo-2D will be the first mission to return a large, pristine sample from a body that formed from beyond the Main Asteroid Belt.