Early results from NASA’s DART mission

Since NASA’s Double Asteroid Redirection Check (DART) spacecraft deliberately slammed into the asteroid moonlet Dimorphos on Sept. 26—altering its orbit by 33 minutes—the investigation group has been digging into the implications of how this planetary protection method might be used sooner or later, if such a necessity ought to ever come up.

This has included additional evaluation of the “ejecta”—the various tons of asteroidal rock displaced and launched into space by the impression—the recoil from which considerably enhanced DART’s push in opposition to Dimorphos.

Continued observations of that evolving ejecta have given the investigation group higher understanding of what the DART spacecraft achieved on the impression web site. DART group members offered a preliminary interpretation of their findings through the American Geophysical Union’s Fall Assembly on Thursday, Dec. 15, in Chicago.

“What we will study from the DART mission is all a part of a NASA’s overarching work to know asteroids and different small our bodies in our solar system,” stated Tom Statler, this system scientist for DART at NASA headquarters in Washington, and one of many presenters on the briefing.

“Impacting the asteroid was simply the beginning. Now we use the observations to review what these our bodies are manufactured from and the way they have been fashioned—in addition to learn how to defend our planet ought to there ever be an asteroid headed our manner.”

Central to this effort are detailed, post-impact science and engineering analyses of knowledge from the world’s first planetary protection know-how demonstration. Within the weeks after impression, scientists turned their focus towards measuring the momentum switch from DART’s roughly 14,000 mile per hour (22,530 kilometer per hour) collision with its goal asteroid.

Scientists estimate DART’s impression displaced over two million kilos (a million kilograms) of the dusty rock into space—sufficient to fill six or seven rail vehicles. The group is utilizing that knowledge—in addition to new info on the composition of the asteroid moonlet and the traits of the ejecta, gained from telescope observations and pictures from DART’s ride-along Mild Italian CubeSat for Imaging of Asteroids (LICIACube) contributed by the Italian Area Company (ASI)—to study simply how a lot DART’s preliminary hit moved the asteroid, and the way a lot got here from the recoil.

“We all know the preliminary experiment labored. Now we will begin to apply this data,” stated Andy Rivkin, DART investigation group co-lead on the Johns Hopkins Utilized Physics Lab (APL). “Learning the ejecta made within the kinetic impression—all of it derived from Dimorphos—is a key manner of gaining additional insights into the character of its floor.”

Observations earlier than and after impression, reveal that Dimorphos and its bigger guardian asteroid, Didymos, have comparable make-up and are composed of the identical materials—materials that has been linked to strange chondrites, much like the most typical sort of meteorite to impression the Earth. These measurements additionally took benefit of the ejecta from Dimorphos, which dominated the mirrored mild from the system within the days after impression. Even now, telescope photographs of the Didymos system present how solar radiation stress has stretched the ejecta stream right into a comet-like tail tens of hundreds of miles in size.

Placing these items collectively, and assuming that Didymos and Dimorphos have the identical densities, the group calculates that the momentum transferred when DART hit Dimorphos was roughly 3.6 occasions better than if the asteroid had merely absorbed the spacecraft and produced no ejecta in any respect—indicating the ejecta contributed to transferring the asteroid greater than the spacecraft did.

Precisely predicting momentum switch is central to planning a future kinetic impression mission if one is ever wanted, together with figuring out the scale of the impactor spacecraft and estimating the quantity of lead-time vital to make sure that a small deflection would transfer a probably harmful asteroid off its path.

“Momentum switch is likely one of the most necessary issues we will measure, as a result of it’s info we would wish to develop an impactor mission to divert a threating asteroid,” stated Andy Cheng, DART investigation team lead from Johns Hopkins APL. “Understanding how a spacecraft impression will change an asteroid’s momentum is essential to designing a mitigation technique for a planetary protection situation.”

Neither Dimorphos nor Didymos poses any hazard to Earth earlier than or after DART’s managed collision with Dimorphos.