NASA and SpaceX Launch DART to test asteroid defence capability

Remember the last time a 10km wide asteroid hit Earth? Of course you don’t because it caused a nuclear winter that wiped out 2 thirds of all the world’s species including every land animal that weighed over 25kg. Don’t worry though, this time around we have a plan to avoid such an event from ever happening again. On Wednesday morning, NASA and SpaceX launched the Double Asteroid Redirection Test, also known as DART, onboard Falcon 9. Built by the Johns Hopkins Applied Physics Laboratory at the direction of NASA’s Planetary Defense Coordination Office, this mission is humanity’s very first planetary defense technology demonstration, which if successful, could be matured and implemented if the need arises.

So how does it work? DART will make use of the kinetic impactor technique, or in other words, it will literally crash onto an asteroid named Dimorphos and alter its orbit around a larger asteroid named Didymos. This binary system is an eclipsing binary, meaning that the smaller moonlet, Dimorphos, passes in front of and behind Didymos as seen from Earth. This enables the Earth-based telescopes to measure the variances in the brightness of the combined system to accurately determine the orbit of the moonlet. This same technique will be used to observe the changes in orbit after the impact of the spacecraft, which will be smashing into it at over 6 kilometers per second. And event that is currently scheduled in the mid 2022. This was also strategically chosen to minimize the distance between Earth and Didymos, allowing for clearer and more accurate observations.

Just to be clear, this asteroid is not on a path to collide with Earth and poses no actual threat. This is why NASA has chosen such a location for the test. Even after the collision, the orbital change will only be slight. It is afterall, just a demonstrator mission. You may ask how such a small change could really help? Well, if you can predict a potential impact years beforehand, just a slight change in trajectory makes a huge difference over such a long period of time. You do certainly want to predict these things well in advance though, which is why our detection systems are so important.

Also flying alongside DART is the Light Italian Cubesat for Imaging of Asteroids, and as the name suggests, it is built by the Italian Space Agency to monitor all effects of the impact and beam it back to Earth. It’ll provide the researchers an even closer look of the crater and the evolution of the debris produced by the collision, enabling them to verify the efficacy of the impact.