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IMAGE '23 luncheon: The DART Mission

Humanity’s First Planetary Defense Test Mission to Deflect an Asteroid

Approximately 65 million years ago a large asteroid slammed into Earth and caused a mass extinction event of which the dinosaurs were the most well-known victims. In the past, our planet has been continually hit by small and large extraterrestrial bodies. Some of them, like the event 65 million years ago caused mass extinctions on a global scale where smaller ones resulted in devastation of a lesser magnitude. There is no reason to believe that we will not be subject to other impacts that could cause destruction and possibly extinction of many lifeforms including ours.

During the annual SEG Gravity and Magnetic Luncheon, Paul Abell who is Chief Scientist for Small Body Exploration in the Astromaterials Research and Exploration Science Division at the NASA Johnson Space Center will discuss details on NASA’s Double Asteroid Redirection Test (DART). The mission of this program was to validate the impact of deflection technique for planetary defense. On September 26, 2022, the DART spacecraft impacted asteroid Dimorphos and successfully altered its orbit about its larger companion, asteroid Didymos. The test spacecraft weighing about 1,200 pounds and slammed into Dimorphos at approximately 14,000 mph, to change the rock’s velocity and trajectory. This was the first time that humanity attempted to change the movement of a celestial object. The results are teaching us how such a kinetic impact technology can be used to deflect asteroids that may be on a collision course with our planet.

The DART test was considered successful and changed Dimorphos’ orbit by 33 minutes. This first ever test of planetary defense took place 7 million miles from Earth and it released over 1,000 tons of material into space.

The Hubble telescope captured images of larger sized material that includes several dozen boulders that range in size from 3 feet to 22 feet in diameter. These rocks most likely were not shattered pieces that broke loose from the asteroid’s surface after impact but were already scattered on the exterior of the asteroid. Those pieces are drifting away from Dimorphos at a slow speed of around 0.5 miles per hour. The total mass of the detected boulders is about 0.1% the mass of the asteroid. This occurrence can cause an issue as hitting an approaching asteroid could result in a cluster of threatening rocks heading in our direction.

The European Space Agency has an upcoming mission using the Hera spacecraft that will launch in 2024 and arrive at Dimorphos in late 2026. Hera will perform a detailed post-impact survey that hopefully will shed light into how the boulders were lifted (ejected plume or seismic wave hitting the asteroid and shaking it) and their precise trajectories.



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