Throughout its already long history, NASA has promoted programs of very different colors, scopes, and impacts, including those that they have allowed us —y they want to do it again— step on the moon Few are however as fascinating as DART, an acronym for Double Asteroid Redirection Test. And it is so by the nature of the mission: its main objective was not to explore planets, nor to deploy a powerful astronomical instrumentbut to teach us how to defend our planet from asteroids.
The culminating moment of the mission was reached at end of septemberwhen the DART mission ship impacted Dimorphos, satellite of the sistema binario Didymos. The objective was exactly that: to complete a crash that would alter its orbit and to evaluate how effective a similar strategy would be if one day we needed to. protect us from an asteroid that threatens the Earth.
“The mission shows that NASA tries to prepare for whatever the universe throws at us. We take our role as defenders of the planet seriously.” the administrator stood out of the space agency, Bill Nelson. Rhetoric aside, the mission was a milestone for several reasons: it is the first time that humanity has managed to deliberately change the displacement of a celestial object and — NASA itself emphasizes — the first large-scale demonstration of asteroid deflection.
“An Important Step”
That the operation succeeded in altering the orbit of Dimorphos is something we already know. since the beginning of octoberwhen the US agency explained that the collision had altered its orbit: if before the mission Dimorphos took 11 hours and 55 minutes to orbit Didymos, after the collision the movement was shortened by about 32 minutes until staying at 11 h and 23 min.
“The result is an important step in understanding the full effect of DART’s impact with its target asteroid,” worth Lori Glazefrom NASA’s Division of Planetary Sciences.
Now the agency has wanted to delve deeper into the balance, expanding the information on the results achieved with DART thanks to the measurements and observations that it has completed over the last few months. One of the issues that has been fixed is the amount of rock and dust that was “ejected” after the collision. Not long ago, NASA had already obtained images that showed the plume of more than 10,000 kilometers formed by that material after the blow.
The new results have been exposed by the researchers of the DART mission during a summit of the American Geophysical Union held this week in Chicago. And they are fascinating. His calculations show that the shock, at about 22,530 km/hit displaced more than a million kilos of rock from the asteroid into space, enough to fill six or seven train cars.
NEW @HUBBLE_space images taken after @NASA‘s Double Asteroid Redirection Test (DART) mission reveal the #Didymos-Dimorphos system now has two tails of dust, ejected from the impact on 27 September 2022 at 01:14 CEST ????https://t.co/WFMkEOTSJv pic.twitter.com/7PWwpmhWtD
— ESA Science (@esascience) October 20, 2022
“Everything we can learn from the DART mission is part of NASA’s overall work to understand asteroids and other small bodies in our Solar System.” points out the agency: “Impacting the asteroid was just the beginning. Now we use the observations to study what these bodies are made of and how they formed, as well as how to defend our planet.”
“Studying the ejecta produced in the kinetic impact, all derived from Dimorphos, is a key way to gain more information about the nature of its surface,” by Andy Rivkinco-leader of the DART research team at the Applied Physics Laboratory from Johns Hopkins APL, in the United States. Observations have also revealed that Dimorphos and Didymos have a similar composition and form from the same material, related to ordinary chondrites.
“Putting these pieces together and assuming Didymos and Dimorphos have the same densities, the team calculates that the momentum transferred when DART hit Dimorphos was approximately 3.6 times higher than if the asteroid had simply absorbed the spacecraft and produced no ejecta.” adds the space agency on its official website, for which the data shows that “the ejection contributed to moving the asteroid more than the spacecraft.”
Cover image: NASA/Johns Hopkins APL