Last year, NASA’s Double Asteroid Redirection Test (DART) spacecraft collided with a Great Pyramid-sized asteroid called Dimorphos in a first test of planetary defence. The mission was to deliberately alter the asteroid’s trajectory through space to study the effectiveness of the deflection technique. The results of the collision have now been released in five studies in the journal Nature.
The collision caused the asteroid’s orbit around another space rock to shrink, completing an orbit 33 minutes faster than before the impact. This means that a mission to smash into a dangerous asteroid heading towards Earth would probably be able to divert it away from the planet.
The DART spacecraft was the size of a golf cart and collided with the asteroid’s rocky surface, causing the spacecraft to shatter into pieces.
The impact ejected at least one million kilograms of rock from Dimorphos’s 4.3-billion-kilogram mass, forming a tail that stretched for tens of thousands of kilometres behind the asteroid.
Various telescopes watched as the tail shifted and evolved under the pressure of the Sun’s rays, with the Hubble Space Telescope detecting a second tail that had disappeared by 18 days after the impact.
Researchers are continuing to study the data from the DART mission to learn more about the physics, chemistry and geology of both Dimorphos and Didymos. These observations will continue for several weeks until the asteroids become too faint for many telescopes to see.
