Scientists back planetary defence mission to 'nudge' asteroid out of orbit

Space scientists have urged ministers to fund a mission to find out if it is possible to nudge an asteroid off its trajectory, and avoid a catastrophic collision with Earth.

The European Space Agency (ESA) has joined up with Nasa for the world’s first planetary defence operation, which aims to study the effect of crashing a into small rock dubbed ‘Didymoon’, which is orbiting an asteroid called Didymos A.

The joint Aida mission, which stands for Asteroid Impact & Deflection Assessment, is made up of Nasa’s Double Asteroid Redirection Test (Dart) spacecraft, which will smash into the little satellite, and the ESA’s Hera mission which will then study the impact afterwards.

But the mission depends on agreement by ministers who are meeting in Seville later this month to decide which projects will be funded in the coming years.

Ahead of the meeting, a group of 1,200 scientists, including the Astronomer Royal Lord Rees, have signed an open letter to ministers warning of the danger of not funding the mission.

“As citizens of our Solar System, we need to expand our body of knowledge of the universe in which we live and how we can protect our planet from hazards originating in space,” they write.

“Near-Earth asteroids will either strike the Earth’s surface or explode in a fire all at low altitude, in both cases causing severe damage over regions of thousands of square kilometers or more.

“Unlike other natural disasters, an asteroid impact with Earth is not only one we know how to predict, but one we can prevent, by means that just need to be tested. Today, we are the first generation of humans who have the necessary technology to try to change the trajectory of an asteroid.

“We strongly urge governments to keep the upcoming Hera mission high on the agenda...providing new and vital knowledge necessary to protect ourselves and future generations.”

Asteroids are left over matter from the formation of planets and range in size from a few feet to tens of miles.

Just like Earth, they orbit the Sun and sometimes come dangerously close to Earth, yet currently there is nothing that can be done to deflect an incoming threat.

There are tens of millions of asteroids larger than 30 feet that would have an energy larger than a small nuclear weapon if they entered the Earth’s atmosphere. So far, scientists have identified just 21,443, fewer than 20 per cent of the total.

The call for funding was made at a press conference in Berlin ahead of the ministerial in Spain.

“New asteroids are now being discovered at the rate of some four per day", said Dr Patrick Michel, AIDA/Hera Principal Investigator, who is based at the Cote d’Azu Observatory in Nice.

“We need a coordinated international strategy for near-Earth object impact mitigation.

“The Aida collaboration will give us the unique possibility to test our capabilities to deflect an asteroid, combined with fascinating science.”

Nasa’s Dart mission is due to launch within the next 12 months, arriving at the binary asteroid system in 2022, where it will immediately crash into the 525ft wide Didymos B ( Didymoon), which is circling the half mile wide Didymos A

The system, which was discovered in 1966, orbits the Sun every 771 days and is classed as a potentially hazardous asteroid to Earth

The team are hoping the impact will change the orbit around Didymos, which would be the first time any body in the Solar System has been moved by humans.

Following the collision,  the Esa’s Hera spacecraft will arrive in January 2027 carrying instruments that will measure the impact crater