A recent breakthrough in NASA’s DART mission highlights the importance of planetary defence systems.
NASA’s Double Asteroid Redirection Test (DART) has successfully impacted its asteroid target after ten months of flying in space. At 7:14 p.m. EDT on Monday, mission control at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, announced the successful impact. DART, the world’s first planetary defence technology demonstration, smashed its target in the agency’s first attempt to move an asteroid in space.
The significance of DART’s impact with an asteroid
DART’s impact with the asteroid Dimorphos, part of NASA’s planetary defence strategy, demonstrates a viable mitigation technique for protecting the planet from an Earth-bound comet or asteroid, if one were discovered.
NASA Administrator Bill Nelson stated: “At its core, DART represents an unprecedented success for planetary defence, but it is also a mission of unity with a real benefit for all humanity.
“As NASA studies the cosmos and our home planet, we’re also working to protect that home, and this international collaboration turned science fiction into science fact, demonstrating one way to protect Earth.”
Dimorphos, a small body just 160 metres in diameter, was targeted by the DART mission. The asteroid orbits a larger, 780-metre asteroid called Didymos. Neither Dimorphos nor Didymos pose a threat to Earth.
The mission has shown that NASA can successfully navigate a spacecraft to intentionally collide with an asteroid to deflect it, a technique known as kinetic impact.
Now, Dimorphos will be observed by the investigation team to confirm that DART’s impact altered its orbit around Didymos. It is estimated that the impact should shorten Dimorphos’ orbit by about 1%, or roughly ten minutes. The team will use ground-based telescopes, ensuring that the deflection of the asteroid is precisely measured; one of the primary purposes of the full-scale test.
Why is planetary defence so important?
Nearby asteroids and comets pose a very real threat to Earth. Serious damage on a local scale can be caused by an impact of any size, and bigger near-Earth objects (NEOs) have the potential to cause large-scale destruction. If humans do not take the necessary steps to prevent major impacts, they are bound to occur.
NASA’s DART mission aims to demonstrate a potential technology for deflecting an asteroid off a predicted impact course with Earth. The recent breakthrough that occurred on Monday has revealed a viable solution to avoid an asteroid or comet impacting our planet.
Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA Headquarters in Washington, stated: “Planetary Defence is a globally unifying effort that affects everyone living on Earth.
“Now we know we can aim a spacecraft with the precision needed to impact even a small body in space. Just a small change in its speed is all we need to make a significant difference in the path an asteroid travels.”
About the DART mission
DART was able to identify and distinguish between the two asteroids by using the Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO), together with a sophisticated guidance, navigation, and control system that works in tandem with Small-body Manoeuvring Autonomous Real Time Navigation (SMART Nav) algorithms.
Together, the systems guided the spacecraft through the final 56,000 miles of space into Dimorphos, intentionally crashing into it at approximately 14,000 miles per hour in an effort to reduce the asteroid’s orbital speed.
Images of the asteroid’s surface and collision were captured by DRACO and DART’s CubeSat companion Light Italian CubeSat for Imaging of Asteroids (LICIACube), provided by the Italian Space Agency, to help researchers better characterise the effectiveness of kinetic impact in deflecting an asteroid.
Lindley Johnson, NASA’s Planetary Defence Officer, said: “DART’s success provides a significant addition to the essential toolbox we must have to protect Earth from a devastating impact by an asteroid.
“This demonstrates we are no longer powerless to prevent this type of natural disaster. Coupled with enhanced capabilities to accelerate finding the remaining hazardous asteroid population by our next Planetary Defence mission, the NEO Surveyor, a DART successor could provide what we need to save the day.”
As the asteroids are located within seven million miles of Earth, a global team is using dozens of telescopes stationed around the world and in space for observation. In the next few weeks, they will characterise the ejecta produced and precisely measure Dimorphos’ orbital change to determine how effectively DART deflected the asteroid. The results from this will assist in improving scientific computer models critical to predicting the effectiveness of this technique as a method for asteroid deflection and planetary defence.
APL Director Ralph Semmel said: “This first-of-its-kind mission required incredible preparation and precision, and the team exceeded expectations on all counts.
“Beyond the truly exciting success of the technology demonstration, capabilities based on DART could one day be used to change the course of an asteroid to protect our planet and preserve life on Earth as we know it.”
In approximately four years from now, the European Space Agency’s Hera project will carry out thorough surveys of both Dimorphos and Didymos, focusing particularly on the crater left by DART’s collision.
DART is directed by NASA to the Johns Hopkins Applied Physics Laboratory.
