The SUfarce Dust Analyzer (SUDA ): Compositional Mapping of Europa's Surface.

The Surface Dust Analyzer (SUDA) instrument onboard NASA's Europa Clipper Flagship mission measures the composition of dust particles populating the thin exospheres around the Galilean moons of Jupiter. Since these grains are direct samples from the moon's icy surface, the unique data from SUDA will constrain the composition and geological history of surface and subsurface materials. SUDA will search for and analyze the composition and nature of active and recent plumes, and also identify particles ejected from Io's volcanoes. Our data will constrain the origins of surface non-ice materials, exchange processes involving the entire exosphere-surface-interior system, and help assess the habitability of Europa.

SUDA is a time-of- flight, reflectron-type impact mass spectrometer, optimized for a high mass resolution that only weakly depends on the impact location on its target. The mass spectrometer has a resolution of m/Δm ~ 200 and is capable to detecting either the cations or the anions generated in an impact. The high purity iridium coated impact target enables the detection of trace amounts (< 1 ppm) of salts, amino acids, and fatty acids embedded in the ice matrix of the particles ejected from the surface. The velocity sensor in front of the mass spectrometer measures the velocity component of the incoming grain parallel to the instrument's boresight with 1% uncertainty. This data allows SUDA to constrain the ejecta's origin on Europa's surface with an uncertainty of about half of the spacecraft altitude.

A flight-like engineering model of the SUDA instrument has been built in order to demonstrate its performance through calibration experiments using NASA's SSERVI/IMPACT dust accelerator facility at he University of Colorado, Boulder, with a variety of cosmo-chemically relevant dust analogues. The effective mass resolution of m/Δm of 150-300 is achieved for the mass range of interest m = 1u - 150u. The instrument has recently passed its Critical Design Review and the team is in the process of fabricating the flight instrument.