Hera asteroid mission takes stunning images of Mars’ moon Deimos

A space exploration mission to study an asteroid that NASA deliberately crashed a spacecraft into three years ago has taken stunning bonus images of Mars and its moon Deimos en route to its final destination. 

NASA’s Double Asteroid Redirection Test (DART) in 2022 was an attempt to show that bodies on a collision course with our planet could be deliberately redirected to avoid catastrophic impact.  Observations from Earth showed that by smashing the 610-kilogram craft into the distant asteroid Dimorphos at 6.6 kilometres per second, NASA successfully changed the asteroid’s orbit. Dimorphos presents no risk to Earth and was merely acting as a test subject.

Hera is a subsequent European Space Agency mission designed to get a closer look at the effect of the crash. The craft is around the size of a small car, weighing 1081 kilograms when fully fuelled. It launched from Cape Canaveral, Florida, on 7 October 2024 aboard a SpaceX Falcon 9 rocket and did a flyby of Mars on 12 March 2025 on the way to the asteroid, which it won’t reach until October 2026.

Hera came as near as 5000 kilometres to the surface of Mars, receiving a gravity boost that will fling it onwards to Dimorphos. The manoeuvre shortened its journey time by many months and saved it fuel.

While it was so close to Mars, it was also able to turn on a trio of sensors and take several detailed photographs of the planet and Deimos in the same frame. A black and white camera with a resolution of 1020 by 1020 pixels was used to capture the images, as well as an infrared camera and a hyperspectral imager that can sense a range of colours beyond the limits of the human eye.

Hera was moving at 9 kilometres per second relative to Mars and was able to image the 12.4-kilometre-long Deimos from just 1000 kilometres away. It could also photograph the side of the moon that is tidally locked away from Mars, which is less commonly captured.

The initial concept behind the Hera mission was for it to be present when DART collided with Dimorphos, but delays in funding made that impossible. It will now arrive several years after the impact.

The mission also carries two miniature satellites, or CubeSats, called Juventas and Milani. Rather than orbiting Dimorphos, these will fly in front of it, making sweeping passes at progressively smaller and riskier distances to gather data. Both are expected to eventually land on the asteroid to get a closer look, once they have done all they can at a distance.