The Hera probe from the European Space Agency (ESA) recently captured spectacular images of Deimos, the smallest moon of Mars, during a close flyby.
Deimos, the moon of Mars, appears in silhouette against the red planet, here seen in light blue in an infrared image, captured by ESA's Hera probe during a flyby on March 12, 2025.
Credit: ESA
Launched in 2024, the Hera mission's primary objective is to collect data on Dimorphos, an asteroid impacted by NASA's DART mission in 2022. To reach its target, Hera used Mars' gravitational assist, taking advantage of this flyby to test its scientific instruments.
Among these instruments, the Hyperscout H hyperspectral imager captured an infrared image of Deimos and Mars. This technology allows for the observation of details invisible to the naked eye, using 25 different spectral bands to analyze the surface composition.
Deimos, located approximately 14,600 miles (23,500 km) from the surface of Mars, is a synchronously rotating moon. This means it always presents the same face to Mars, making this image even more valuable for scientists.
The scientific team of ESA's Hera mission, including astrophysicist and guitarist Sir Brian May (left) and principal investigator Patrick Michel (right), celebrates the reception of images from the Mars flyby on March 12, 2025 at ESA's control center in Darmstadt, Germany.
Credit: ESA This mission highlights the importance of international collaborations in space exploration. The data collected by Hera will contribute to a better understanding of asteroids and the development of planetary defense strategies.
The images captured by Hera are not just technical feats; they also open new perspectives on our Solar System. Each close flyby and each image enriches our knowledge of the celestial bodies around us.
The Hera mission continues its journey to Dimorphos, with the hope of gathering more information about these small celestial bodies that populate our Solar System.
What is a gravitational assist?
A gravitational assist is a technique used in astronautics to modify the trajectory and speed of a space probe by using the gravity of a planet or another celestial body. This method saves fuel and allows for more efficient travel to distant destinations.
When a probe passes near a planet, it is attracted by its gravity, which accelerates the probe and alters its trajectory. This interaction is carefully calculated so that the probe can continue its journey to its final destination with optimized speed.
This technique has been used in many space missions, including the Voyager, Galileo, and now Hera missions. It is essential for exploring remote regions of the Solar System without requiring prohibitive amounts of fuel.
Why study asteroids like Dimorphos?
Asteroids, like Dimorphos, are remnants of the formation of the Solar System. Studying them helps us better understand the processes that led to the formation of planets and other celestial bodies.
In addition to their scientific interest, asteroids represent a potential threat to Earth. Studying their composition and structure is crucial for developing planetary defense strategies, such as the DART mission that impacted Dimorphos to test the possibility of deflecting an asteroid.
The data collected by missions like Hera contribute to refining our impact prediction models and developing technologies to protect our planet. These missions illustrate the importance of space research for the security of humanity.