On its recent swing by Mars, NASA’s Europa Clipper took the opportunity to capture infrared images of the Red Planet. The data will help mission scientists calibrate the spacecraft’s thermal imaging instrument so they can be sure it’s operating correctly when Europa Clipper arrives at the Jupiter system in 2030.
The mission’s sights are set on Jupiter’s moon Europa and the global ocean hidden under its icy surface. A year after slipping into orbit around Jupiter, Europa Clipper will begin a series of 49 close flybys of the moon to investigate whether it holds conditions suitable for life.
A key element of that investigation will be thermal imaging — global scans of Europa that map temperatures to shed light on how active the surface is. Infrared imaging will reveal how much heat is being emitted from the moon; warmer areas of the ice give off more energy and indicate recent activity.
The imaging also will tell scientists where the ocean is closest to the surface. Europa is crisscrossed by dramatic ridges and fractures, which scientists believe are caused by ocean convection pulling apart the icy crust and water rising up to fill the gaps.
“We want to measure the temperature of those features,” said Arizona State University’s Phil Christensen, principal investigator of Europa Clipper’s infrared camera, called the Europa Thermal Imaging System (E-THEMIS). “If Europa is a really active place, those fractures will be warmer than the surrounding ice where the ocean comes close to the surface. Or if water erupted onto the surface hundreds to thousands of years ago, then those surfaces could still be relatively warm.”
This picture of Mars is a colorized composite of several images captured by Europa Clipper’s thermal imager. Warm colors represent relatively warm temperatures; red areas are about 32 degrees Fahrenheit (0 degrees Celsius), and purple regions are about minus 190 F (minus 125 C).
Why Mars
On March 1, Europa Clipper flew just 550 miles (884 kilometers) above the surface of Mars in order to use the planet’s gravitational pull to reshape the spacecraft’s trajectory. Ultimately, the assist will get the mission to Jupiter faster than if it made a beeline for the gas giant, but the flyby also offered a critical opportunity for Europa Clipper to test E-THEMIS.
For about 18 minutes on March 1, the instrument captured one image per second, yielding more than a thousand grayscale pictures that were transmitted to Earth starting on May 5. After compiling these images into a global snapshot of Mars, scientists applied color, using hues with familiar associations: Warm areas are depicted in red, while colder areas are shown as blue.
By comparing E-THEMIS images with those made from established Mars data, scientists can judge how well the instrument is working.
“We wanted no surprises in these new images,” Christensen said. “The goal was to capture imagery of a planetary body we know extraordinarily well and make sure the dataset looks exactly the way it should, based on 20 years of instruments documenting Mars.”
NASA’s Mars Odyssey orbiter, launched in 2001, carries a sister instrument named THEMIS that has been capturing its own thermal images of the Red Planet for decades. To be extra thorough, the Odyssey team collected thermal images of Mars before, during, and after Europa Clipper’s flyby so that Europa scientists can compare the visuals as an additional gauge of how well E-THEMIS is calibrated.
Europa Clipper also took advantage of the close proximity to Mars to test all the components of its radar instrument in unison for the first time. The radar antennas and the wavelengths they produce are so long that it wasn’t possible for engineers to do that in a clean room before launch. The radar data will be returned and analyzed in the coming weeks and months, but preliminary assessments of the real-time telemetry indicate that the test went well.
To leverage the flyby even further, the science team took the opportunity to ensure that the spacecraft’s telecommunication equipment will be able to conduct gravity experiments at Europa. By transmitting signals to Earth while passing through Mars’ gravity field, they were able to confirm that a similar operation is expected to work at Europa.
Europa Clipper launched from NASA’s Kennedy Space Center in Florida on Oct. 14, 2024, via a SpaceX Falcon Heavy, embarking on a 1.8 billion-mile (2.9 billion-kilometer) journey to Jupiter, which is five times farther from the Sun than Earth is. Now that the probe has harnessed the gravity of Mars, its next gravity assist will be from Earth in 2026.
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More About Europa Clipper
Europa Clipper’s three main science objectives are to determine the thickness of the moon’s icy shell and its interactions with the ocean below, to investigate its composition, and to characterize its geology. The mission’s detailed exploration of Europa will help scientists better understand the astrobiological potential for habitable worlds beyond our planet.
Managed by Caltech in Pasadena, California, NASA’s Jet Propulsion Laboratory in Southern California leads the development of the Europa Clipper mission in partnership with the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, for NASA’s Science Mission Directorate in Washington. APL designed the main spacecraft body in collaboration with JPL and NASA’s Goddard Space Flight Center in Greenbelt, Maryland, NASA’s Marshall Space Flight Center in Huntsville, Alabama, and Langley Research Center in Hampton, Virginia. The Planetary Missions Program Office at NASA Marshall executes program management of the Europa Clipper mission. NASA’s Launch Services Program, based at NASA Kennedy, managed the launch service for the Europa Clipper spacecraft.
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