In-Situ Mass Spectrometry of Atmosphereless

Dust particles, like photons, carry information from remote sites in space and time. From knowledge of the dust particles ’ birthplace and their composition, we can learn about the remote environment out of which the particles were formed. This approach is called “Dust Astronomy ” which is carried out by means of a dust telescope in space. Dust Astronomy provides a novel method to directly analyze surface composition of atmosphereless planetary objects. All atmosphereless objects are exposed to the ambient meteoroid bombardment that erodes the surface and generates ejecta particles at a wide range of ejection speeds. Objects with radii bigger than 1000 km keep all particles with ejection speeds lower than ~1000 m/s. Therefore, such objects are enshrouded in clouds of dust particles that have been lifted by meteoroid impacts from the bodies ’ surfaces. These particles move on ballistic trajectories, most of which re-collide with their parent object. In-situ mass spectrometric analysis of these particles from an orbiting spacecraft provides spatially resolved mapping of the surface composition of the object. Particulates ejected from the surface of objects with a size above ~ 1500 km can be directly analyzed with an in-situ impact ionization mass spectrometer in orbit around the body (the method works at orbital speeds down to about 1 km/s). The composition of smaller objects (planetary satellites, asteroids, KBOs, and cometary nuclei) can be explored by fast fly-bys through their eject