In a scientific article published this week in the journal NATURE there is a detailed report on the successful demonstration of the kinetic impactor technology by DART: a reconstruction of the impact itself, a report on the timeline until the impact, detailing the location and nature of the impact site, and the documentation of the size and shape of Dimorphus
Ever since NASA’s DART (Dual Asteroid Redirection Experiment) mission successfully hit its target nearly five months ago on Sept. 26 — changing the orbit of the lunar asteroid Dimorphus by 33 minutes — the DART team has been hard at work analyzing data collected from the Defense Experiment mission. The first planetary (protection of the earth) in the world.
The DART mission used a technique for deflecting asteroids known as a “kinetic impactor”, which simply means smashing something into something else – in this case, a spacecraft into an asteroid. From the data, the DART investigation team, led by the Johns Hopkins Laboratory of Applied Physics in Laurel, Maryland, found that a kinetic impactor mission like DART could be effective in altering an asteroid’s trajectory, a big step toward the goal of preventing future asteroid impacts to Earth. These findings were published in the journal Nature.
“I was delighted when DART collided head-on with an asteroid in the world’s first demonstration of planetary defense technology, and that was just the beginning,” said Nicola Fox, deputy director of the Science Mission Administration at NASA Headquarters in Washington. “These findings add to our fundamental understanding of asteroids and build a foundation for the possibility that humanity You will be able to protect the Earth from a potentially dangerous asteroid by changing its trajectory.”
In one of the articles in the journal there is a detailed report on the successful demonstration of the kinetic impactor technology by DART: a reconstruction of the impact itself, a report on the timeline until the impact, detailing the place and nature of the impact site, and the documentation of the size and shape of Dimorphos.
The authors note that the successful autonomous homing of DART on a small asteroid, with limited early observations, is a critical first step on the path to developing kinetic impactor technology as a viable operational planetary defense capability.
The findings show that the interception of an asteroid with a diameter of about 800 meters, such as Dimorphos, can be performed without a preliminary reconnaissance mission, although a preliminary reconnaissance would provide valuable information for planning and predicting the outcome. What is necessary is sufficient notice – at least a few years, but preferably decades. “Nevertheless,” the authors say in the article, DART’s success “creates optimism about humanity’s ability to protect the Earth from an asteroid threat.”
Another paper uses two independent approaches based on radar observations and light curves from Earth. The investigation team came up with two consistent measurements of the change in lap time as a result of the kinetic impact: 33 minutes, plus or minus one minute. This large change indicates that the recoil was due to the material Excavated from the asteroid and ejected into space by the impact (known as ejecta) contributed a significant momentum change to the asteroid, beyond that of the spacecraft itself.
In a kinetic impact the key is that the boost the asteroid receives comes not only from the colliding spacecraft, but also from this recoil of the ejecta. The authors conclude: “In order to serve as a proof of concept for the planetary defense kinetic impactor technique, DART had to demonstrate that an asteroid could be homed in a high-speed encounter and that the target’s trajectory could be changed. DART did both successfully.”
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