Hera planetary defence mission successfully launched

Hera, the European Space Agency’s (ESA) first planetary defence mission, was successfully launched aboard a SpaceX Falcon 9 rocket, from Cape Canaveral in Florida. The satellite is now heading to a unique target among the 1.3 million known asteroids of our Solar System.

If an incoming asteroid were to threaten Earth, what could be done to cope with the situation? On September 26th 2022, NASA’s Double Asteroid Redirection Test (DART) mission performed humankind’s first test of asteroid deflection by crashing into the Great-Pyramid-sized Dimorphos moonlet. This resulted in a shift of its orbit around the mountain-sized Didymos main asteroid.

Next comes ESA’s own contribution to the international Asteroid Impact & Deflection Assessment (AIDA) collaboration: the Hera mission will travel to Dimorphos so as to gather vital close-up data regarding the deflected body and turn DART’s grand-scale kinetic impact experiment into a well-understood and potentially repeatable planetary defence technique. Hera will provide in particular accurate measurements concerning the asteroid’s mass, as well as crucial information about its make-up and structure, which are essential to interpret the outcome of the impact.

The Hera mission, will also carry out the most detailed exploration to date of a binary asteroid system – although binaries make up 15% of all known asteroids, they have never been studied in detail. Hera will also perform technology demonstration experiments, including the deployment of ESA’s first deep space ‘CubeSats’ – shoebox-sized spacecraft to venture closer than the main mission then eventually land – and an ambitious test of 'self-driving' for the main spacecraft, based on vision-based navigation. The OHB System AG (Germany), as prime contractor of Hera, led the industrial consortium, including responsibility for the overall spacecraft design, development, assembly, and testing.