On its voyage toward the outer solar system, NASA’s Europa Clipper spacecraft made a scheduled diversion and seized a remarkable photographic opportunity. In one frame, the uncrewed Europa Clipper captured Mars alongside its small moons, Phobos and Deimos, shining in infrared light. The image provides a unique glimpse at this planetary trio and gave mission engineers an opportunity to optimize the spacecraft’s thermal camera as it flew by the Red Planet.
From approximately 560,000 miles away, Europa Clipper’s infrared camera recorded 200 images over a span of 20 minutes on Feb. 28. These images were combined to unveil the heat signatures of Mars, Phobos, and Deimos. The outcome is a striking view: Mars takes center stage, with Deimos appearing as a tiny luminous dot in the upper left, and Phobos situated closer. Engineers enhanced the image to reveal the faint moons.
On Mars, a dark area near the top indicates the icy northern polar cap. A round section depicts Elysium Mons, one of Mars’ massive volcanoes. The Martian moons are seldom observed together with their host planet. The first occasion that both Phobos and Deimos were photographed simultaneously occurred in November 2009 by the Mars Express orbiter, as reported by the European Space Agency.
Scientists possess limited knowledge about Phobos and Deimos, two of the smallest recognized moons in the solar system. Phobos is the larger of the two, measuring about 14 miles across, and orbits Mars three times daily. Deimos, which is merely seven or eight miles wide, completes an orbit around Mars every 30 hours. Researchers remain uncertain about the origins of these moons. Some speculate they may be asteroids captured in orbit around Mars, while others propose they could be fragments of Mars itself, ejected by a massive impact billions of years prior.
The recent image from Europa Clipper was captured using one of the spacecraft’s thermal sensors, engineered to detect heat rather than visible light. This instrument will subsequently be employed to investigate Jupiter’s moon Europa, a frozen environment thought to contain a salty ocean beneath its icy surface — and potentially the conditions suitable for supporting life. The instrument, known as the Europa Thermal Emission Imaging System, or E-Themis, should assist in identifying locations where Europa’s inner ocean may be interacting with its frozen exterior.
The spacecraft utilized Mars’ gravity in March to adjust its trajectory, a technique called a gravity assist, en route to the outer solar system. That close encounter offered a moment to test instruments and gaze upon Mars. Just days later, another spacecraft made a brief visit for a gravity assist and some photographs. That spacecraft is participating in the European Hera mission to investigate the asteroid NASA deliberately impacted three years ago.
Europa Clipper was launched from Florida in October 2024 and is expected to reach the Jupiter system in 2030. Upon arrival, it will conduct nearly 50 flybys of Europa, collecting comprehensive data on its surface, interior, and chemistry. Should NASA determine that Europa is a hospitable location, a subsequent Europa mission could return to ascertain whether any life forms exist.