After years of development, assembly, and testing, the Johns Hopkins Applied Physics Laboratory (APL) Europa Clipper team in Laurel, Maryland, delivered to NASA’s Jet Propulsion Laboratory (JPL) in Southern California the spacecraft’s plasma detection instrument, called the Plasma Instrument for Magnetic Sounding (PIMS); the spacecraft’s Europa Imaging System wide-angle camera (EIS WAC); and its radiation monitor (RadMon), which will gauge the wave of electrons bombarding the spacecraft as it performs 40 to 50 flybys of Europa. The instruments and flight system components were delivered to JPL in June 2022.
Slated to take off in 2024, NASA’s Europa Clipper will explore Europa, a moon of Jupiter with an ocean containing twice as much water as all of Earth’s oceans combined which may have the conditions to support life. The spacecraft will observe Europa’s space environment, surface, and interior, helping to determine the thickness of the moon’s icy crust, the depth and salinity of its ocean, and signs of potential plumes venting from subsurface water into space.
The instruments and flight system components APL delivered play a critical role in achieving those objectives. The team’s final instrument delivery — the Europa Imaging System narrow-angle camera (EIS NAC) — is scheduled for this fall.
Plasma Instrument for Magnetic Sounding (PIMS)
Radiation has a profound effect on Europa. As Jupiter’s enormous magnetic field washes over the moon, its interactions with the electrically conductive salty ocean induce a magnetic field around the moon, which Europa Clipper’s magnetometer will measure to determine Europa’s ocean depth and conductivity as well as the thickness of its icy shell.
The hot soup of charged particles, or plasma, moving in tow with Jupiter’s magnetic field at 60 miles (100 kilometers) per second, however, creates its own magnetic fields, distorting Europa’s induced field and making it hard to interpret.
That’s where Europa Clipper's plasma detection instrument, called the Plasma Instrument for Magnetic Sounding (PIMS), comes in. Using four metal receptacles called Faraday cups, PIMS will measure the plasma’s density, temperature, and velocity around Europa, which physicists can then use to develop computational models to subtract the plasma’s effect on Europa’s magnetic field.
PIMS’s Faraday cups were specially designed to deal with Jupiter’s radiation environment. At about 8 inches (20 centimeters) wide and 3 inches (8 centimeters) deep, each cup was designed like a little stadium, with tiers of progressively smaller metal rings and insulating spacers that lead to a flat detector plate at the bottom.
Europa Imaging System Wide-Angle Camera (EIS WAC)
Europa Clipper’s wide-angle camera (WAC) — one of two cameras in the spacecraft’s Europa Imaging System (EIS) — has one of the largest sensors to be flown in deep space: an 8 megapixel sensor that can capture color and stereoscopic images as good as about 23-feet (7-meter) per-pixel resolution.
A refractive telescope, the WAC captures light directly, passing it through a series of lenses built to withstand Jupiter’s radiation and focusing the light on a metal oxide semiconductor detector like those found in cell phones and digital cameras. The camera will capture wide swaths of Europa’s landscape on every flyby, providing new information about materials and geologic features on the surface.
In combination with its narrow-angle counterpart, the WAC will image roughly 90% of Europa’s surface at better than 330 feet (100 meters) per pixel, providing an unprecedented global dataset of Europa’s geology.
Using those images, scientists will determine what geologic processes acting in the ice shell might have created (or continue to create) Europa’s many surface features.
In coordination with the mission’s radar team, the camera will help scientists interpret structures beneath the surface and search for fresh deposits from Europa’s purported water vapor plumes, which, if found, would reveal an ongoing exchange between the subsurface water and the icy surface. Finally, the WAC could help identify ideal landing sites for a potential future lander mission.
Read more about the delivery here.