NASA’s DART Data Validates Kinetic Impact as Planetary Defense Method | NASA
▻https://www.nasa.gov/feature/nasa-s-dart-data-validates-kinetic-impact-as-planetary-defense-method
This image depicts the footprint of the Double Asteroid Redirection Test (DART) spacecraft and its two long solar panels over the spot where it impacted asteroid Dimorphos. The largest boulder near the impact site is about 6.5 meters (21 feet) across. DART took the underlying image three seconds before impact.
Credits: NASA/Johns Hopkins APL
Since NASA’s Double Asteroid Redirection Test (DART) successfully impacted its target nearly five months ago, on Sept. 26 — altering the orbit of the asteroid moonlet Dimorphos by 33 minutes — the DART team has been hard at work analyzing the data collected from the world’s first planetary defense test mission.
The DART mission employed an asteroid-deflection technique known as a “kinetic impactor,” which in simplest terms means smashing a thing into another thing — in this case, a spacecraft into an asteroid. From the data, the DART investigation team, led by the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, found that a kinetic impactor mission like DART can be effective in altering the trajectory of an asteroid, a big step toward the goal of preventing future asteroid strikes on Earth. These findings were published in four papers in the journal Nature.
“I cheered when DART slammed head on into the asteroid for the world’s first planetary defense technology demonstration, and that was just the start,” said Nicola Fox, associate administrator for the Science Mission Directorate at NASA Headquarters in Washington. “These findings add to our fundamental understanding of asteroids and build a foundation for how humanity can defend Earth from a potentially hazardous asteroid by altering its course."
The first paper reports DART’s successful demonstration of kinetic impactor technology in detail: reconstructing the impact itself, reporting the timeline leading up to impact, specifying in detail the location and nature of the impact site, and recording the size and shape of Dimorphos.
The authors, led by Terik Daly, Carolyn Ernst, and Olivier Barnouin of APL, note DART’s successful autonomous targeting of a small asteroid, with limited prior observations, is a critical first step on the path to developing kinetic impactor technology as a viable operational capability for planetary defense.
Their findings show intercepting an asteroid with a diameter of around half a mile, such as Dimorphos, can be achieved without an advance reconnaissance mission, though advance reconnaissance would give valuable information for planning and predicting the outcome. What is necessary is sufficient warning time — several years at a minimum, but preferably decades. “Nevertheless,” the authors state in the paper, DART’s success “builds optimism about humanity’s capacity to protect the Earth from an asteroid threat.”
The second paper uses two independent approaches based on Earth-based lightcurve and radar observations. The investigation team, led by Cristina Thomas of Northern Arizona University, arrived at two consistent measurements of the period change from the kinetic impact: 33 minutes, plus or minus one minute. This large change indicates the recoil from material excavated from the asteroid and ejected into space by the impact (known as ejecta) contributed significant momentum change to the asteroid, beyond that of the DART spacecraft itself.
