NASA’s Europa Clipper spacecraft, on its way to explore Jupiter’s moon Europa, recently made use of a flyby of Mars on March 1, 2025, to calibrate its advanced thermal imaging system. This flyby provided a unique opportunity for the spacecraft to capture infrared images of the Red Planet, which will be instrumental in ensuring the accuracy of its instruments when it arrives at Europa in 2030. The infrared images captured during the flyby will not only aid in the calibration of the instruments but also test the spacecraft’s performance for future scientific endeavors. These details are highlighted in a recent update from the Jet Propulsion Laboratory, shedding light on the mission’s progress and preparations for its monumental journey ahead.
The Infrared Snapshot of Mars
The Europa Clipper used its thermal imaging camera to capture multiple infrared images of Mars, creating a detailed global view of the Red Planet. The resulting images were colorized to highlight temperature differences across the surface. Warm regions appeared red, while the coldest areas appeared purple, showcasing the stark contrast between various Martian terrains. Notably, the northern polar cap of Mars showed temperatures as low as minus 190°F (-125°C), while warmer regions hovered around 32°F (0°C). This snapshot not only provides stunning visuals but also serves as a key step in the calibration of the spacecraft’s thermal imager, which will play a pivotal role in its future mission to study Europa’s icy surface and underlying ocean.
Credit: NASA/JPL-Caltech/ASU
Why Mars? The Gravity Assist
On March 1, Europa Clipper flew just 550 miles (884 kilometers) above Mars, using the planet’s gravity to adjust its trajectory on its journey toward Jupiter. This gravity assist enabled the spacecraft to gain speed, shortening its path and allowing it to reach Jupiter’s system faster. This flyby was more than just a trajectory adjustment; it was an invaluable opportunity for Europa Clipper to test its instruments under real-world conditions. The spacecraft captured over 1,000 grayscale images during the brief 18-minute period of thermal imaging, transmitting them back to Earth for analysis starting May 5.
By comparing these new infrared images with data from established Mars exploration missions, such as NASA’s Mars Odyssey, the team ensured that Europa Clipper’s instruments were calibrated correctly. “We wanted no surprises in these new images,” said Phil Christensen, the principal investigator of Europa Clipper’s infrared camera. “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.”
Preparing for the Mission to Europa
The main mission goal of Europa Clipper is to investigate Europa, Jupiter’s icy moon, to determine whether it might harbor conditions suitable for life. The spacecraft will use its thermal imaging system, known as E-THEMIS, to examine the moon’s surface and identify signs of recent geological activity. “We want to measure the temperature of those features,” said Christensen. “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.”
The thermal imaging will allow scientists to pinpoint areas where Europa’s ocean might be in contact with the surface. This information will help determine whether the moon is geologically active and capable of supporting microbial life. Europa’s surface is heavily fractured, with ridges and cracks likely caused by the movement of its subsurface ocean, and studying the temperature of these features could offer clues about its geological activity and its potential for supporting life.
Testing Key Components for the Journey Ahead
The Mars flyby also provided an opportunity to test other essential components of Europa Clipper’s radar and telecommunication systems. The spacecraft’s radar antennas and the wavelengths they produce were tested in unison for the first time during the flyby. Engineers had been unable to test these components together before launch due to their size and complexity. Early telemetry data indicates that the tests were successful, ensuring that Europa Clipper will be able to collect the necessary radar data for its study of Europa’s ice-covered ocean.
In addition, the flyby allowed the team to verify that the spacecraft’s telecommunications systems would work effectively in the gravity field of Europa, facilitating future gravity experiments on the moon. By transmitting signals to Earth while passing through Mars’ gravity, the team confirmed that the same operation would be possible when Europa is reached, ensuring the spacecraft’s ability to carry out gravity measurements as part of its scientific mission.
