Micrometeorites constantly blast fragments of Europa’s surface into space. The ejecta are individually small, but scientists estimate that half a ton (about 500 kilograms) of Europa’s surface material floats above the moon at all times.
Europa Clipper’s SUrface Dust Analyzer, or SUDA, will scoop up the ejecta and identify its chemistry, revealing Europa’s surface composition including potential organic molecules. SUDA is uniquely capable of detecting salts in the dust/ice grains. The grains’ speed and direction will tell SUDA their origin on Europa’s surface. If a subsurface ocean or reservoir is venting material into space as plumes (like the geyser Old Faithful), SUDA will analyze it to help determine if Europa’s water is suitable for some form of life.
“Once the lid on the SUDA bucket opens, SUDA is like a shark with an open mouth.”
How It Works
When dust enters SUDA, it passes through a series of metal mesh grids that measure the dust’s speed and trajectory, which identify the dust’s area of origin on Europa’s surface.
The dust then strikes a metal target plate. “It splatters dust grains into individual molecules and ionizes some of them,” said SUDA investigation scientist Murthy Gudipati, a planetary scientist and astrophysicist. Once ionized (electrically charged), the molecules must obey SUDA’s electrical field, which funnels them to a detector. An ion’s mass-to-charge ratio determines how long it takes to reach the detector. The timing reveals the molecule’s mass and composition. “We can resolve amino acids, sulfates, whatever,” Gutipati said. “We can identify whether organic molecules are abiotic or biomolecules.”How We'll Use It
How We'll Use It
A dust grain’s trajectory helps scientists know where on Europa’s surface it came from. Knowing the grain’s speed helps pin down the dust’s origin even more accurately.
Each dust particle’s chemistry is a data point indicating the composition of one spot on Europa’s surface.
SUDA will study how much Europa surface material originated from elsewhere, said Sascha Kempf, SUDA’s principal investigator and a planetary scientist at University of Colorado-Boulder. “When using Europa's surface material to draw conclusions about the moon's interior, you first need to know how much surface material is not from Europa,” he said. “All the Galilean moons are exchanging material all the time, just as Earth, Mars, and the Moon do.”Meet the Team
Meet the Team
“We are not a life-finding mission,” Gudipati said. “Europa Clipper’s goal is to understand Europa’s ocean and the moon’s habitability. My hope is that SUDA provides compositional information to improve our understanding of that ocean.”
The Galileo mission performed some Europa flybys, blazing the trail for Europa Clipper, Kempf said. “Observations from Galileo flybys matched very nicely the model predictions, so we really have a solid understanding of how much dust is there and how much we’ll detect,” he said. “Galileo’s team did the work that allowed us to plan and design an instrument optimized for the environment around Europa. We didn’t have to design a Swiss army knife of an instrument. The instrument is tailored specifically to what we know is there and what we want to learn.”