Europa Clipper’s instruments and other spacecraft hardware are attached to the spacecraft.
The Europa Imaging System, or EIS (pronounced “ice”), will capture Europa’s valleys, ridges, dark bands, and other features in profound detail. EIS has a wide-angle camera (WAC) and a narrow-angle camera (NAC). Each camera has an eight-megapixel sensor sensitive to visible wavelengths of light and a small range of near-infrared and ultraviolet wavelengths. The NAC pivots 60 degrees on two axes. Both cameras will produce stereoscopic images and have filters to acquire color images.
EIS will map about 90 percent of Europa at 330 feet (100 meters) per pixel. That’s six times more of Europa’s surface at five times better resolution than the finest images from the Galileo spacecraft. When the spacecraft is close to Europa during flybys, EIS will produce images with a resolution 100 times better.Quick Facts
|A wide-angle camera and a narrow-angle camera|
|Eight-megapixel sensor in each camera|
|Narrow-angle camera has a gimbal to pivot 60 degrees on two axes|
|EIS will map 90 percent of Europa at 330 feet (100 meters) per pixel (six times more of Europa’s surface, at five times better resolution than ever before)|
|Can image individual surface features at as little as one and a half feet (half a meter) per pixel|
|Both cameras will produce stereoscopic images|
|Both cameras will produce color images|
How It Works
The wide-angle camera, or WAC, sees large portions of Europa’s landscape. The narrow-angle camera, or NAC, has a more “zoomed-in” view and sees smaller portions of the landscape, but with more pixels per unit area than the WAC.
“During flybys, the WAC will cover a swath of the surface in stereo and in color…stereo topography will reveal a lot about the surface structure.”
The NAC is a reflecting telescope and uses a large mirror to collect light. Then other mirrors and lenses direct a condensed beam onto an eight-megapixel detector called a complementary metal oxide semiconductor (commonly known as CMOS ). Cell phones and digital cameras also use CMOS detectors, which are perhaps the most widely-used NASA spinoff technology in the world. The WAC has the same kind of sensor, but is a refracting telescope instead of a reflecting telescope. It lets the light directly in and uses lenses to focus the light onto its detector.
How We'll Use It“With the narrow-angle camera, we’ll image certain areas of Europa at half a meter per pixel…We’ll see features on the surface that we haven’t seen before.”
How We'll Use It
Scientists will use EIS to study surface features and how they relate to each other and to sub-surface structures. The instrument will search for signs of recent geologic activity on the moon’s surface. It will also look for potential plumes venting material into space. EIS’s three-dimensional views will allow scientists to measure surface heights. Color images will provide information about Europa’s surface materials.
“We’re not quite sure how some of the features on Europa’s surface formed,” said Lynnae Quick, a planetary scientist at NASA’s Goddard Space Flight Center and a member of Europa Clipper’s imaging team. “Really high-resolution images will give us clues as to how these features formed.”
Meet the Team
The EIS team is based at the Johns Hopkins Applied Physics Laboratory (APL) in Maryland. EIS’s principal investigator, planetary scientist Elizabeth “Zibi” Turtle, previously was an associate of the Cassini mission’s imaging and radar teams. Turtle also spearheads NASA’s planned Dragonfly mission. Dragonfly will launch in the late 2020s and travel to Saturn’s moon Titan. Dragonfly is a rotorcraft lander that will fly in Titan’s atmosphere and explore that moon like never before.
“The EIS instrument’s stereo topography will reveal a lot about Europa's surface structure,” Turtle said of EIS’s 3D imaging capabilities. “Combined with the REASON instrument, which can penetrate into the moon’s surface, we’ll be able to understand both the surface and subsurface structure.”