European Space Agency awards contract to protect Earth from asteroids
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    European Space Agency awards contract to protect Earth from asteroids

    Illustration of the DART craft approaching the asteroids. © NASA/Johns Hopkins

    The European Space Agency (ESA) yesterday signed a contract worth €129.4 million for the launch of HERA, a mission intended to defend the planet from asteroids.

    Hera will join up with the DART programme run by the American space agency NASA to send a probe for the first time ever to a binary asteroid system. The probe is due to be launched in July next year.

    In the 1998 film Armageddon, Bruce Willis piloted a spacecraft to land on an asteroid heading for earth, plant a nuclear device and blow the asteroid into space dust.

    In reality, the approach is slightly different.

    The DART spacecraft will deliberately collide with the smaller part of the binary system. Hera will then follow up and carry out a detailed post-impact survey, the information to be used to develop a repeatable asteroid deflection technique.

    Hera will also use new technology like autonomous navigation to move around the asteroid system in a way similar to driverless cars on earth, collecting information on the composition and structure of asteroids.

    The target of the mission is the Didymos binary asteroid – two asteroids that orbit around a shared centre point. The larger of the two bodies measures 780m, and the smaller, Dimorphos 160m – about the size of the Great Pyramid.

    The system has been classified as hazardous to Earth. It was discovered in 1996 using the telescope at Kitt Peak National Observatory in Arizona.

    It is the smaller body, named Dimorphos, that will be hit by the DART probe, with impact planned for October 2022.

    Hera, meanwhile, will arrive at the end of 2026, and spend about six months collecting data.

    The impact by DART is expected to change Dimorphos orbiting speed by about 0.5mm/s, and change the length of its orbit around the main body by about 200s.

    A fraction of one per cent, but enough to be measured roughly with Earth-based telescopes,” the ESA said.

    The Hera contract has been awarded to a consortium representing 17 ESA member states, led by Germany, which will be responsible for design and integration, the main navigation cameras, tanks, thrusters, high-gain antenna, reaction wheels, and mass memory unit.

    Belgium is developing Hera’s on-board computer and software, the brain of the spacecraft, as well as its power conditioning and distribution unit, the heart of its electrical subsystem. It is also contributing to Hera’s Japanese-developed thermal imager and CubeSats operations centre at Darmstadt in Germany.

    Alan Hope
    The Brussels Times