The European probe Hera arrived at its destination yesterday, November 4th, after a two-year journey. Its objective is to study the binary system Didymos, composed of a main asteroid 800 meters in diameter and a small moon, Dimorphos, 150 meters across. On September 26, 2022, the DART mission impacted Dimorphos, altering its orbit and making it the first object in the solar system whose trajectory has been modified by human action.
According to Adriano Campo Bagatin, a professor at the UA and a member of the mission's coordinating team, a thorough study of the system is necessary to observe the effects of the DART collision. The aim is to determine if a crater was created, if Dimorphos was deformed, to analyze its internal structure using radar sounding, and to see if the collision also affected Didymos.
Until June 2, 2027, Hera will conduct in-situ observations. It carries two nanosatellites, Juventas and Milani, which will be deployed in January 2027. Juventas will feature a radar for a complete tomography of Dimorphos, while Milani will measure dust microparticles. This data, along with images and spectroscopic analyses from Hera, will contribute to planetary defense.
The Planetary Sciences Group at the UA is involved in studying the internal structure of the asteroids and analyzing the material ejected by the DART impact. The mission will deepen the understanding of planetary defense strategies, as knowing the collision effects will help prepare future plans to deflect asteroids that could impact Earth, such as the one expected to graze the planet in 2029.
On November 25th, the ESA will present the first detailed images of Dimorphos during an event broadcast from the Natural History Museum in Berlin.
