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When NASA’s Double Asteroid Redirection Test spacecraft deliberately crashed into asteroid Dimorphos in September 2022, the impact may have caused “global deformation” of the space rock, according to new research.
The goal of the DART mission was to conduct a full-scale test of asteroid deflection technology for the sake of planetary defense and to see if there would be a kinetic effect, such as when a spacecraft hits an asteroid at 13,645 miles per hour (6.1 kilometers per second). — would be enough to change the motion of a celestial body in space.
Dimorphos is a moonlet asteroid that orbits a larger parent asteroid known as Didymos. Neither pose a threat to Earth, but the double asteroid system was an excellent target to test deflection technology because Dimorphos’ size is comparable to asteroids that could pose a threat to Earth.
Since the day of impact, astronomers have used data from ground-based telescopes to determine that the DART spacecraft had shifted Dimorphos’ orbital period (or how long it takes to make a single revolution around Didymos) by about 32 to 33 minutes. But another important piece of information needed to understand how to deflect asteroids that may be on a potential collision course with Earth in the future is the composition of space rocks.
Different types of asteroids that pose a threat—hard, stony asteroids or rubble mounds that are loose piles of rock held together by gravity—require different deflection techniques.
The DART mission ended at impact, but before colliding with Dimorphos, the spacecraft transmitted an incredibly detailed image of the small asteroid’s rock-covered surface, helping researchers learn more about how space rock was formed.
Astronomers were also able to make follow-up observations with ground- and space-based telescopes and with the Italian LICIACube satellite, which briefly followed the DART mission and imaged its aftermath for 5 minutes and 20 seconds.
Observations revealed that the impact released a huge chunk of material into space.
Now the researchers have taken the research a step further by putting all of this data into software to help answer important remaining questions, such as determining how the asteroid responded to the impact and what type of crater was left behind.
The results suggested that the DART impact reshaped the entire asteroid rather than creating a simple crater on Dimorphos. A study describing the findings was published Monday in the journal Nature Astronomy.
The findings could prepare astronomers for what they find during future Dimorphos flybys to better understand the effects of asteroid deflection technology.
Recreate the DART effect
A team of researchers modeled the effect using the Bern smoothed particle hydrodynamics shock physics code to reach their results.
It is “a computational tool designed to simulate impact events. Shock physics codes are important in the study of collisions and impact processes in general. “It combines a variety of models, including material models and porosity models, to accurately represent the physical conditions during hypervelocity impact events, such as high pressures and temperatures.” sciences at the Institute of Physics at the University of Bern in Switzerland.
The software has been validated by replicating other impacts, including Japan’s Hayabusa2 spacecraft crashing a small copper impactor into asteroid Ryugu in 2019.
The team ran 250 simulations to recreate the first two hours following the DART impact based on the data they had, varying factors they didn’t know about, “such as the closeness of the rocks together, their density, the porosity and porosity of the material.” general harmony. We also made some reasonable assumptions based on the physical properties of meteors similar to Dimorphos,” Raducan said.
After running their simulations, the team focused on the simulation that most closely matched the original DART data.
The results showed that Dimorphos is a pile of rubble made of rocky material shed from the Didymos asteroid and held together by weak gravity.
Study co-author Dr. “On Earth, the gravitational force is such that it causes crater formation for short periods of time, creating a typical crater cone angle of about 90 degrees,” said Martin Jutzi. The Working Group made a statement. “What we saw with DART hitting Dimorphos was a much wider launch cone angle, extending up to 160 degrees, primarily influenced by the curved shape of the asteroid’s surface. “And the crater continued to expand because both gravity and material adhesion are very low.”
As a result, the crater grew to encompass the entirety of Dimorphos, completely changing the shape of the asteroid.
Hera’s mission
Raducan and Jutzi are part of the research team participating in the European Space Agency’s Hera mission. This mission will launch a spacecraft to observe the consequences of the DART collision in October and arrive in late 2026. It will come with a pair of CubeSats. The mission will examine the composition and mass of Dimorphos, how it transformed upon impact, and determine how much momentum was transferred from the spacecraft to the asteroid.
“Our simulations show that Dimorphos’ initial flying saucer shape is blunted on the impact side: If you thought Dimorphos initially looked like a chocolate M&M, it will now look like a bite has been taken from it!” Raducan said:
Queen guitarist and astrophysicist Sir Brian May, along with his collaborator chemical engineer and materials researcher Claudia Manzoni, also shared stereoscopic images to help the team learn more about the reshaping event.
The team believes that 1% of Dimorphos’ entire mass was ejected into space by the impact, while 8% of the asteroid’s mass was displaced.
“Hera probably won’t find the crater left by DART,” Raducan said. “What he will discover instead will be a very different body.”
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