Europa Clipper will carry science instruments more advanced and sensitive than anything that’s explored this Jovian moon before. Through thoughtful collaboration, the mission’s scientists will attempt to discover whether Europa hosts environments suitable for life. The spacecraft will not carry life-seeking instruments. Instead, we must first answer other questions, such as:
Does Europa really contain an ocean beneath its shell of ice?
How deep is the ocean?
Does the chemistry of the ocean seem friendly for microbes?
Is Europa’s ice shell active, allowing surface material to migrate to the ocean and vice versa, perhaps enriching the ocean with molecules from above that could serve as "food" for organisms?
*Europa Clipper will use hardware used for communicating with Earth for its gravity/radio science investigations.
Europa Clipper’s visible-light cameras (extending slightly into near-infrared and ultraviolet wavelengths) will map Europa at far better resolution than previous missions. The spacecraft’s two infrared cameras will map the moon’s surface composition, temperature, and roughness. Together, the cameras and other instruments will reveal much about Europa’s chemistry and geologic activity.
A wide-angle camera and a narrow-angle camera, each with an eight-megapixel sensor, will produce high-resolution color and stereoscopic images of Europa. They will study geologic activity, measure surface elevations, and provide context for other instruments.
The thermal imager uses infrared light to distinguish warmer regions on Europa where warm liquid water may be near the surface or might have erupted onto the surface. It will also measure surface texture to understand the small-scale properties of the surface.
Different atoms and molecules emit, absorb, and reflect various wavelengths of light in telltale ways. As such, light carries information about materials it has interacted with. Europa Clipper’s spectrometer and spectrograph will dissect incoming infrared and ultraviolet light to decode that information and reveal the composition of Europa’s surface, and of particles in space near Europa.
By collecting ultraviolet light with a telescope, and creating images, the mission’s ultraviolet spectrograph will help determine the composition of Europa’s atmospheric gases and surface materials. It will also search near Europa for signs of plume activity.
The mission’s infrared spectrometer will map the distribution of ices, salts, organics, and the warmest hotspots on Europa. The maps will help scientists understand the moon’s geologic history and determine if Europa’s suspected ocean is suitable for life.
Plasma and Magnetic Field
Jupiter’s magnetic field, the largest in the solar system, traps the charged particle gas – plasma – that fills the space surrounding Europa (and the rest of the Jupiter system). As Europa moves in its orbit, the magnetic field varies. Time-variations of the magnetic field induce Europa to produce its own magnetic field that, in turn, will provide clues to the structure of the moon’s interior.
The magnetometer investigation aims to confirm that Europa’s ocean exists, measure its depth and salinity, and measure the moon’s ice shell thickness. It will also study Europa’s ionized atmosphere and how it interacts with Jupiter’s ionized atmosphere.
Europa’s ionosphere, and plasma trapped in Jupiter’s magnetic field, distort magnetic fields near Europa. PIMS Faraday cups will distinguish those distortions from Europa’s induced magnetic field, which carries information about Europa’s ocean.
Radar & Gravity
Europa’s physical properties affect radio signals, which will help reveal the moon’s interior. A gravity experiment will analyze frequency shifts in the spacecraft’s signals to Earth (the same signals used in communication and navigation) to study Europa’s internal structure. A radar instrument will transmit radio into Europa’s icy shell and analyze the bounced signals to “see” internal features.
Europa and its gravity field flex as the moon’s non-circular orbit carries it closer, then farther, from Jupiter. Measuring Europa’s gravity at various points in the moon’s orbit will show how Europa flexes and help reveal its internal structure.
Ice-penetrating radar will probe Europa’s icy shell for the moon’s suspected ocean and study the ice’s structure and thickness. It will also study the moon’s surface elevations, composition, and roughness, and search the moon’s atmosphere for plumes.
Radar and cameras “look” at things from afar, while other science instruments such as magnetometers sense the environment immediately around the spacecraft. Still others collect gas and dust in space to identify their chemical makeup. Europa Clipper’s complementary dust spectrometer and neutral gas mass spectrometer perform such collections; they are the mission’s “hands-on” experiments.
The mass spectrometer will analyze gases in Europa’s faint atmosphere and possible plumes. It will study the chemistry of the moon’s suspected subsurface ocean, how ocean and surface exchange material, and how radiation alters compounds on the moon’s surface.
Tiny meteorites eject bits of Europa’s surface into space, and a subsurface ocean or reservoirs might vent material into space as plumes. The dust analyzer will identify that material’s chemistry and area of origin, and offer clues to Europa’s ocean salinity.
Engineers, machinists, and scientists are now building and testing Europa Clipper’s science instruments and other hardware. The spacecraft is currently coming together. The team is refining the spacecraft's flight path to Jupiter and its “tour” of orbits around the planet, in which it will make dozens of Europa flybys.
Whatever Europa Clipper reveals could change our understanding of the solar system, and other planetary systems, forever. "This is a giant step in our search for oases that could support life in our own celestial backyard," said Curt Niebur, Europa program scientist at NASA Headquarters in Washington. "We're confident that this versatile set of science instruments would produce exciting discoveries on a much-anticipated mission."