On September 26, 2022, NASA's DART spacecraft impacted the Dimorphos asteroid at 6.1 km/s. This event altered Dimorphos's orbit around its larger companion, Didymos, and marked the first time humanity demonstrated its ability to deflect an asteroid. This test was designed to show how we might protect Earth from a potential asteroid impact by altering its path.

While DART succeeded, questions remain unanswered. Scientists are eager to understand the exact mass and composition of Dimorphos, assess the structural effects of the impact, and determine the size of the crater formed by the collision. Some even wonder if Dimorphos might be fractured and held together by weak gravity.

ESA's Hera mission will return to Dimorphos to gather crucial close-up data, helping to refine the planetary defense technique demonstrated by DART. Hera will explore the binary asteroid system in unprecedented detail, becoming the first mission to study a binary asteroid in depth-an important step since binary asteroids account for 15% of all known asteroids.

In addition to gathering data, Hera will carry out technology demonstration experiments, including deploying ESA's first deep space CubeSats-small spacecraft that will approach the asteroid more closely and eventually land. The mission will also test advanced autonomous navigation technology based on visual data.

By the conclusion of Hera's mission, Dimorphos will become the most studied asteroid in history. Understanding asteroids of this size is crucial, as an impact could potentially wipe out an entire city. While the dinosaurs had no means of defense against asteroids, through missions like Hera, humanity is learning how to mitigate this threat and improve space safety.

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