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Protection against asteroid impacts

European NEOShield programme

Impact by asteroids or comets: not an impossible nightmare

Significant asteroid impacts have occurred frequently in the past.

These have ranged from the regional devastation caused 100 years ago by the Tunguska event in Siberia: an object of only a few tens of metres in diameter, which nevertheless had the power of 1,000 atomic bombs of the sort dropped on Hiroshima, to 65 million years ago, when another, vastly bigger, asteroid impacted close to the Yucatan Peninsula in Mexico and is most probably responsible for the extinction of half of all animal species, including the dinosaurs.

The probability of another impact of an object in this size range in the next 10,000 years is close to 100 percent, but we do not know when. Of the thousands of already identified asteroids crossing the trajectory of Earth, none is expected to collide with our planet in the next 100 years. However, we only see a fraction of the total expected NEOs in our vicinity ...

As the writer Arthur C. Clarke so pertinently remarked: “The dinosaurs became extinct because they didn't have a space programme.”

The European Union has decided to invest in the protection of the Earth against impact by Near Earth Objects (NEOs), such as asteroids or comets. This European programme is called NEOShield. NEOShield will be the world’s largest international programme of this type, with participating institutions and companies from across Europe, the United States and Russia.

Asteroid deflection space missions should already be possible using current technologies but to date these have not been adapted for such a purpose. The preparation of a demonstrator mission to protect the Earth against NEO imapact is the goal of the NEOShield programme.

Observing an asteroid

Defining a concept

The work of NEOShield will be coordinated from the German Space Agency DLR’s Institute of Planetary Research in Berlin. Under the programme, Airbus Defence and Space will lead the technical work of an industrial consortium in charge of defining the basic concepts of protecting of the Earth against NEOs.

One of the most promising concepts for such a mission is the so-called “kinetic impactor”: a spacecraft slams into the NEO at very high speed, giving it a nudge and causing it to change its orbit very slightly so it deviates from its original collision course. This concept was studied by Airbus Defence and Space a few years ago for the European Space Agency (ESA) and will now be updated and further developed.

The most critical technology challenges for the kinetic impactor are guidance, navigation and control to ensure successful NEO impact. It involves relative speeds in excess of 10km/s and a target precision of only a few metres. For this reason, two Airbus Defence and Space teams will work in parallel with different concepts calling on their own specific expertise and experience. One team from Airbus Defence and Space Satellites has extensive experience of interplanetary missions, including navigation and control over large distances.  The other from Airbus Defence and Space Space Transportation, has successfully demonstrated precise space navigation and rendezvous with launchers and the ATV, the European space cargo vehicle.

Collision course

An international team

Airbus Defence and Space will also oversee the technical studies of the international partners, who will concentrate on two other asteroid deviation concepts. The first is based on the gravitational pull between an object in space and a spacecraft. Known as a gravity tractor, the gravitational pull of a spacecraft in the vicinity of an object such as an asteroid over a long period of time will cause the object to change its orbit. The gravity tractor concept will be investigated by the Carl Sagan Institute in Palo Alto, California, which also carries out similar work for NASA. The other concept is deflection (and not destruction) by an explosion close to the asteroid’s surface. This ‘blast deflection’ concept will be investigated by TsNIIMash, a Russian institution also working for the Russian space agency Roscosmos.

For Airbus Defence and Space, this multi-site project will involve experts in Friedrichshafen (Germany), Stevenage (United Kingdom), Toulouse (France), Les Mureaux (France) and Bremen (Germany). Airbus Defence and Space, Europe’s leading space company will support half of the research and development effort.

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