The importance of what the Dart mission portends for humanity

(MENAFN – Gulf Times)

The success of NASA’s recent Dart mission (Dual Asteroid Redirect Test), which saw a spacecraft deliberately crash into an asteroid to push it into a faster orbit, marked the world’s first test of a planetary defense system designed to prevent a potential meteorite collision with Earth. The relevance of the proof-of-concept mission, which was seven years in the making, directly points to the fact that the Cretaceous mass extinction event that occurred about 66 million years ago killed 78% of all species, including the remaining dinosaurs without birds , likely caused by an asteroid (later named Chicxulub) impacting Earth in present-day Mexico, possibly exacerbated by ongoing flood-volcanic activity in present-day India.
The Dart mission was also the first for humanity to change the motion of a celestial body, the US space agency announced. Findings from the telescopic observations revealed at a Nasa news briefing in Washington confirmed that the Dart spacecraft’s suicide test flight on September 26 achieved its primary goal: changing the direction of an asteroid through sheer kinetic force. Astronomical measurements two weeks after the impact showed that the target asteroid impacted slightly closer to the larger parent asteroid it orbits and that its orbital period decreased by 32 minutes. NASA chief Bill Nelson told reporters announcing the results. “It looked like a movie plot, but this wasn’t Hollywood.”
Last month’s impact, 10.9 million kilometers from Earth, targeted an asteroid called Dimorphos, about the size of a football field and orbiting a parent asteroid about five times larger called Gemini once every 11 hours and 55 minutes. The test flight ended with the Dart impactor, no bigger than a refrigerator, slamming directly into Dimorphos at about 22,531 km/h. Comparing pre- and post-impact measurements of the Dimorphos-Gemini pair as they eclipse each other shows that the orbital period has shortened to 11 hours and 23 minutes, with the smaller object impacting tens of meters closer to its parent.
The result “showed that we are capable of deflecting a potentially dangerous asteroid of this size” if it had been detected well enough in advance, said Lori Glaze, director of NASA’s planetary science division. “The key is early detection.” Neither of the two asteroids involved, nor Dart itself, posed a real threat to Earth. But an asteroid the size of Dimorphos, while not capable of posing a threat to the entire planet, could level a large city with a direct hit. Scientists had predicted that Dart’s impact would shorten Dimorphos’ orbital path by at least 10 minutes, but would consider a change as short as 73 seconds a success. So the actual change of over half an hour, with a margin of uncertainty plus or minus two minutes, exceeded expectations.
Launching on a SpaceX rocket in November 2021, the Dart flew most of its journey under the guidance of flight managers on the ground, with control handed over to the craft’s autonomous navigation system in the final hours of the journey. Dimorph and Gemini are both tiny compared to the cataclysmic Chicxulub. Smaller asteroids are much more common and of greater theoretical concern in the short term, making the Gemini pair suitable test subjects for their size, according to Nasa scientists and planetary defense experts. Also, the relative proximity of the two asteroids to Earth and their dual configuration made them ideal for the Dart mission.
The moon Dimorphos is one of the smallest astronomical objects to receive a permanent name and is one of 27,500 known near-Earth asteroids of all sizes tracked by Nasa. Although none are known to pose a foreseeable risk to humanity, NASA estimates that many more asteroids remain undetected in the near-Earth region.

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