By Chris Skeldon 
The asteroid Dimorphos, which deviated from its course during an experiment in 2022, will be explored by the European Hera probe, which will make a long journey in October to analyze how to protect humanity from a potential space threat.
In a scenario worthy of Hollywood, the Double Asteroid Redirection Test (DART) mission ship in 2022 collides with the asteroid Demorphos, the “moon” of a larger celestial body called Didymos. The goal of this unprecedented “planetary defense” test mission was to discover whether it would be possible to divert an asteroid if it one day collided with Earth.
It is estimated that an object with a length of one kilometer, which could cause a global catastrophe such as the extinction of the dinosaurs, collides with our planet every 500 thousand years, and an asteroid with a diameter of 140 meters – the limit of a regional catastrophe – every 20 thousand years.
Among these near-Earth objects, most of which come from the asteroid belt between Mars and Jupiter, practically all of them are known to be one kilometer long and none of them threatens the planet in the next century.
There has also been no immediate threat reported from the 140-metre-long species, but only 40% of the species has been identified. Although this is a natural hazard “among the least likely,” humanity may have “the advantage of being able to take measures to protect itself” from it, said Patrick Michel, the scientist in charge of the European Space Agency’s (ESA) Hera mission.
The asteroid Dimorphos, which was about 11 million kilometers from Earth at the time of impact, had a diameter of about 160 meters and posed no danger.
When it collided with it, NASA was able to deflect it, reducing its orbit by 33 minutes. But it is not known what the effects of the collision were on the small asteroid or what its internal structure was before the collision.
While the experiment helped prove the feasibility of this technology, more is needed to validate it and be able to determine how much energy is needed to effectively ward off a potential threat.
Nanosatellites
At a cost of 363 million euros (about 400 million US dollars or 2.2 billion Brazilian reais at current prices) and equipped with 12 instruments, Hera will transport the two nanosatellites Juventus and Melanie.
The first will land on Dimorphos, an unprecedented feat for such a small object. It is equipped with a low-frequency radar and a gravimeter to explore the asteroid's structure and measure its gravitational field.
The second part will study the composition of this celestial body with the help of a multi-spectral camera and a dust detector.
The window for launching the probe from Cape Canaveral (United States), at the head of a SpaceX Falcon 9 rocket, opens on Monday (7) and continues until October 27.
After flying by Mars in 2025, it will arrive near Dimorphos in December 2026, where it will complete an initial six-month mission. At the end of the experiment, those responsible for the probe will attempt to gently lower it onto Dimorphos or Didymos before turning it off.