The collision of NASA’s Dart spacecraft with the moonlet asteroid Dimorphos is estimated to have moved more than 1,000 tons of rock into space,
The ‘ejecta’ of space rock expelled by the collision was enough to fill six or seven train cars and also altered Dimorphos’ orbit by about 33 minutes, new research presented at the fall meeting of the American Geophysical Union in Chicago.
NASA scientists estimated the momentum transfer from the Dart collision at around 22,530 km/h. Newly available data showed that Dart’s momentum transferred to Dimorphos when it slammed into the asteroid.
The US space agency made history in September when it launched a spacecraft onto an asteroid, making it the first time humans have altered the trajectory of a celestial body.
Dart, or Double Asteroid Redirection Test, was launched in November 2021 and spent months traveling to target Dimorphos – a companion asteroid to the larger Didymos – which was traveling through space at a distance of around 6.8 million miles. miles from Earth.
The space agency hoped to find out if a spacecraft like Dart could deflect asteroids threatening Earth in the future and offer a chance against life-threatening impacts of the type that once wiped out dinosaurs.
Research evaluated ejecta to better understand how slamming spacecraft into potentially deadly asteroids could work as a planetary defense technique.
The scientists used new data on the composition of Dimorphos and the characteristics of the ejecta, obtained from telescope observations and images from Dart’s Light Italian CubeSat for Imaging of Asteroids (LICIACube), provided by the Italian Space Agency (ASI).
Based on the data, scientists were able to tell how far Dart’s initial hit moved the asteroid and how much was from recoil.
“We know that the initial experiment worked. We can now begin to apply this knowledge. Studying the ejecta produced during kinetic impact – all derived from Dimorphos – is a key way to gain new insights into the nature of its surface,” said Andy Rivkin, co-leader of the team at Dart investigation at the Johns Hopkins Applied Physics Lab (APL).
The research also revealed that Dimorphos and Didymos have similar makeup and are made of the same material.
The scientists said that predicting momentum transfer would be essential for planning a future kinetic impact mission, including estimating the size of the impacting spacecraft.
It would also help determine the time needed to ensure a small deviation would move a potentially dangerous asteroid off course in the future, NASA said.
In the new analysis, the space agency found that the momentum transfer on Dart was about 3.6 times greater than if the asteroid had simply absorbed the spacecraft and produced no ejecta, indicating that the ejecta helped move the asteroid more than the spacecraft.
“Momentum transfer is one of the most important things we can measure, because it’s information we would need to develop an impactor mission to deflect a threatening asteroid,” said Andy Cheng, chief of Johns Hopkins APL’s Dart Investigation Team.
“Understanding how a spacecraft impact will change an asteroid’s momentum is critical to designing a mitigation strategy for a planetary defense scenario,” he added.