The European probe Hera has begun close study of the asteroid Didymos and its small satellite Dimorphos. The European Space Agency (ESA) reported this. The craft is currently 25 to 30 kilometers from the pair.
In 2022, the American probe Dart (Double Asteroid Redirection Test) deliberately crashed into Dimorphos. The goal was to test whether such an impact could in future help protect Earth from a dangerous celestial body.
The collision shortened the satellite's orbit around Didymos. More importantly, it slightly changed its trajectory around the Sun.
Dimorphos itself is estimated at about 151 meters across, Didymos at about 780 meters.
Launched in 2024, the small-car-sized Hera probe will move even closer next month, to 20 kilometers. ESA calls this mission a "crash site investigation" worthy of the best robot detective.
Hera carries 25 scientific instruments, as well as a pair of cubesats (Cubesat - miniature satellites the size of a shoebox). They are to examine Dimorphos in even more detail and attempt to land on its surface.
The Dart impact ejected debris and even boulders from Dimorphos, which gave an additional impulse. The trail of these particles stretched thousands of kilometers into space and persisted for months. According to scientists, some of the debris may still be nearby.
Hera will continue studying the consequences of the experiment. These observations will help understand how effective such a planetary defense method can be.