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Name given to asteroid target of ESA’s planetary defence mission

on 24 June 2020

The destination of ESA’s Hera mission for planetary defence, in which Romania also takes part, has finally received its official name. After years of informal nicknames and temporary designations, the smaller of the Didymos asteroid pair has been formally christened ‘Dimorphos’ by the International Astronomical Union.

A near-Earth binary asteroid system, named after the Greek word for ‘twin’, Didymos’s main body measures about 780 m across, with its previously nameless moonlet about 160 m in diameter, approximately the size of Egypt’s Great Pyramid.

In 2022, this moonlet will be the target of NASA’s Double Asteroid Redirection Test (DART), the first full-scale demonstration of an asteroid deflection technology for planetary defence. ESA’s Hera mission will be launched two years later, to perform a close-up survey of Dimorphos, along with its parent asteroid, following DART’s impact.

DART’s kinetic impact into Dimorphos is expected to alter its orbit around Didymos as well as create a substantial crater, which will be studied by the Hera spacecraft when it arrives several years later. The DART impact itself will be recorded by the Italian-made LICIACube CubeSat, deployed from DART several days earlier, with longer-term effects studied by telescopes on Earth’s surface and in space.

“In the past we’ve referred to it as Didymos-B, or Didymoon, but the target of our mission finally has an official name, confirmed by the International Astronomical Union, IAU,” comments Ian Carnelli, managing Hera for ESA.

Find out more details at this link.

Image credit: ESA -