NASA will test 'planetary defence' to stop future asteroid sending Earth 'to Stone Age'

The impact test is expected to take place on October 2, 2022.

DART will fire its engines and crash into the 524ft-wide Didymoon while avoiding the bigger, 2,560ft-wide (780m) parent asteroid.

According to Dr Statler, the smaller asteroid “is more typical of the size of asteroid that could pose the most likely significant threat to Earth”.

But he noted Didymoon is “not necessarily the asteroid that’s going to cause a devastating effect on Earth.”

The test will slightly alter the asteroid’s path – not enough to send it careening off on a wild trajectory, but just enough for NASA to measure any change in its orbit.

The change should be big enough to be observed and measured by telescopes on Earth.