The dual electronics unit for Europa Clipper’s stellar reference unit (also called a star tracker) in a clean room at NASA’s Jet Propulsion Laboratory. There are two units in case one fails during the life of the mission. The purpose of the electronics unit is to take the images from the optical head and process the images to find stars, match them against an onboard catalog, and then tell the spacecraft its orientation in space.
Europa Clipper’s star tracker design was particularly challenging due to the intense Jovian radiation environment. This radiation consists of high-energy charged particles accelerated by Jupiter’s magnetic field. The particles create thousands of bright spots and streaks in star tracker images. To overcome that visual noise, engineers designed the star tracker to filter out the spots and streaks, enabling its computer to concentrate on the stars themselves.