NASA’s DART Mission: A Smashing Success in Defending Earth from Asteroid Threats
Last September, NASA conducted the Double Asteroid Redirection Test (DART) mission to test our capability to defend Earth from possible asteroid threats. The mission has now been deemed a success, with telescopes observing the impact’s effects on the asteroid Dimorphos. The DART spacecraft smashed into Dimorphos, a binary asteroid system located 6.8 million miles from Earth, at 21,000 kilometres per hour.
The impact remarkably shortened Dimorphos’ orbit by around 33 minutes, more than 25 times the minimum benchmark for mission success. In addition, the collision liberated debris which formed a tail stretching more than 1,500 kilometers. The team observed the tail with the Hubble Space Telescope for about three weeks, finding that its morphology is similar to “active asteroids” that have an asteroid-like orbit and comet-like tail. The likeness implies that collisions can “activate” asteroids.
The European Space Agency (ESA) will launch their Hera mission in October 2024, arriving at Didymos two years later. It is anticipated that Hera will conduct a comprehensive investigation of the Didymos-Dimorphos system, including the crater generated from DART's descent. Scientists anticipate that Hera will unravel more information about the DART impact site, investigating the object's rotation state and the geophysics behind solar system formation.
The Hubble Space Telescope observed material being expelled into the cosmos and forming a trail behind the asteroid. A paper led by astronomer Jian-Yang Li of the Planetary Science Institute makes a detailed study of the ejecta, observing a complex morphology of the ejecta, conditioned by the gravitational interaction between the asteroid and the dust under the influence of solar radiation pressure.
The results of the study published in Nature demonstrate that kinetic impactor technology is a viable technique to potentially defend Earth if necessary. The DART mission has been a smashing success and is the first to test this technology at full scale. It has shown that an asteroid can be targeted during a high-speed encounter and that the target’s orbit can be changed. The ESA’s Hera mission will further evaluate the results of the DART experiment and provide a more detailed analysis of the impact’s effects on the system and the geophysics behind solar system formation.
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