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When NASA’s Double Asteroid Redirection Test spacecraft crashed into the tiny asteroid Dimorphos, the impact certainly left its mark.
The intentional collision, which occurred Sept. 26 as a test of asteroid deflection technology, displaced more than 2 million pounds (1 million kilograms) of rock and dust from the asteroid into space. Scientists estimate that it was enough material to fill about six or seven railroad cars.
The insights gained from the collision are helping scientists understand how this planetary defense technique could be used in the future. That’s if an asteroid is ever found to be on a collision course with Earth.
Neither Dimorphos, nor the larger asteroid Didymos that it orbits, poses a threat to Earth, but the system has made target practice excellent.
New findings and images of the impact were shared Thursday at the American Geophysical Union Fall Meeting in Chicago.
“What we can learn from the DART mission is all part of NASA’s overall work to understand asteroids and other small bodies in our Solar System,” said Tom Statler, DART program scientist at NASA, in a statement.
“The asteroid impact was just the beginning. We now use the observations to study what these bodies are made of and how they formed, as well as how to defend our planet if ever an asteroid is headed our way.”
Images captured by space and ground-based telescopes before and after the impact are helping scientists piece together what happened when the spacecraft slammed into Dimorphos at about 14,000 miles per hour (22,530 kilometers per hour).
The DART team calculated that the momentum transfer when the spacecraft hit the asteroid was 3.6 times greater than if the asteroid had absorbed the spacecraft and no material had erupted from the surface. The momentum created when Dimorphos’ surface material erupted into space helped move the asteroid more than the spacecraft did, the researchers said.
“Momentum transfer is one of the most important things we can measure, because this is information we would need to develop an impact mission to deflect a threatening asteroid,” said Andy Cheng, Johns Hopkins DART investigative team. Applied Physics Laboratory in Laurel, Maryland, in a statement.
“Understanding how a spacecraft impact will change an asteroid’s momentum is key to designing a mitigation strategy for a planetary defense scenario.”
The DART mission successfully changed the trajectory of asteroid Dimorphos, marking the first time humanity has intentionally changed the motion of a celestial object in space.
Before impact, it took Dimorphos 11 hours and 55 minutes to orbit Didymos. Now, it takes Dimorphos 11 hours and 23 minutes to go around Didymos. The DART spacecraft changed the lunar asteroid’s orbit by 32 minutes.
Initially, astronomers expected that DART would be successful if it shortened its trajectory by 10 minutes.
