Hera: Target Deimos

ESA’s Hera’s spacecraft’s 12 March 2025 flyby of Mars brings it just 300 km from Deimos, the smaller and further distant of the planet’s two moons. Deimos orbits 20 068 km away from the surface of Mars. This city-sized dusty moon might actually be the leftover of a giant impact on Mars or else a captured asteroid. Hera will image the side of tidally-locked Deimos facing away from Mars. This imagery should help guide to 2026 Japanese-led Martian Moons eXploration Mission, MMX.

Watch the star-studded webcast image release from Hera’s flyby by the mission’s science team on Thursday 13 March, starting at 11:50 CET!

Hera will be using three instruments at a minimum distance of 1000 km from the moon:

-          Asteroid Framing Camera: Two redundant 1020x1020 pixel monochromatic visible-light sensors used for both navigation and scientific investigation.

-          Hyperscout H: Observing in a range of colours beyond the limits of the human eye, in 25 visible and near-infrared spectral bands

-          Thermal Infrared Imager: Imaging at mid-infrared wavelengths to chart surface remperatre, supplied by the Japan Aerospace Exploration Agency, JAXA.

Hera’s flyby send it towards its final destination in late 2026. At 12.4 km across, Deimos is tiny beside Mars but gargantuan compared to the 780-m-long Didymos and 151-m-long Dimorphos asteroids. Dimorphos’s orbit was changed by impacting NASA’s DART mission in 2022. Hera’s close-up data will sharpen scientific understanding of asteroid deflection, helping make Earth safer.

Did you know this mission has its own AI? You can pose questions to our Hera Space Companion!