On March 12, the European probe Hera will perform a flyby of Mars. Scientists will use this opportunity to photograph the Red Planet as well as the “dark side” of its moon Deimos.
On the way to the asteroids
The Hera mission was launched last autumn. Its target is the twin asteroid Didymos. In 2022, the NASA-built DART probe deliberately crashed into its moon, Dimorphos. The purpose of the experiment was to study the possibility of deflecting dangerous celestial targets away from Earth.
The collision had a significant impact on Dimorphos. The impact knocked at least a thousand tons of matter from the surface of the asteroid, which led to a change in its orbit and the formation of a long dust tail. The primary objective of the Hera mission is to study Dimorph and assess how exactly it was affected by the collision.
But in order to catch up with the asteroid, the spacecraft needs to increase its speed. That’s what a meeting with Mars is for. The spacecraft will use the planet’s gravity to accelerate and adjust its trajectory. The maneuver will ensure the arrival of Hera to the target in December 2026.
The encounter with Mars and the other side of Deimos
Hera will perform a flyby of Mars on March 12. The spacecraft will pass at a distance of 5,000 km from its surface. Mission specialists will use this opportunity to test and calibrate Hera’s science instruments and make observations.
Of particular interest is the encounter with Deimos. It is the smaller of the two Martian moons, whose orbit occurs at a distance of 20,000 from the planet’s surface. The origin of Deimos remains a mystery. One theory is that it gathered in orbit from matter dislodged from the surface of Mars during a major collision. According to another, Deimos is an asteroid captured by the planet’s gravity.
Hera will pass just 300 kilometers from Deimos and study its “dark side” — the hemisphere that is never visible from the surface of Mars. It is much less studied than the other hemisphere. Hera will photograph the back side of Deimos, obtain spectra of its surface, and measure its temperature.
The data collected by Hera will be useful in planning Japan’s MMX mission, which will be launched in 2026. Its primary goal is to study the Martian moons. MMX will have to deliver a sample of Phobos matter to Earth, which will help answer the question of the origin of Mars’ moons.
Live broadcast of Mars imagery
The day after the flyby, Thursday, March 13, the Hera science team plans to publish images of Deimos and Mars taken by the spacecraft. The event will be broadcast live on ESA’s Youtube channel.
In addition to mission specialists, the event will also be attended by astronaut Alexander Gerst, famous science fiction writer Andy Weir (author of the novels “The Martian” and “Project Hail Mary”), and an unnamed special guest. The live broadcast will start at 11:50 CET.
