DART mission is a pilot test to see how dangerous asteroids may be deflected to save life on Earth
By Kiran N. Kumar
Approximately 66 million years ago, an asteroid is believed to have caused the mass extinction of dinosaurs and many other species on Earth. Even to this day, the prospect of an approaching asteroid rekindles the fears of survival of life on Earth as NASA emphatically foresees a cataclysmic asteroid impact in the next 100 years.
As per NASA’s listing, all objects that are within 4.6 million miles (7.5 million km) from the Earth and bigger than 492 feet (150 meters) are potentially hazardous, since the effect of the gravitational pull of a larger celestial object can significantly alter its trajectory and hurl itself toward the Earth instead of flying by.
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Next month, the asteroid ‘2022 OE2’ measuring about 700 feet (213 meters) in size or approximately the size of a stadium will fly past the Earth at a distance of 3.2 million miles (5.2 million km) which is far distant from the Moon that is just 239,000 miles (385,000 km) away.
As the 2022 OE2 is one such asteroid carrying a significant risk, NASA is not taking a chance. The Double Asteroid Redirection Test (DART) mission sent in November 2021 is going to crash on Sep 26, not on ‘2022 OE2’ but on a moon asteroid that is smaller but has potential to deflect the course of the bigger asteroid.
The DART mission is, in fact, a pilot to test crashing into the 525 feet (160 m) wide moon called “Dimorphous” that is circling the larger asteroid “Didymos” or 2022 OE2 with a diameter of 2,560 feet (780 meters) and change its trajectory.
The collision with Dimorphous, which is currently located 109.4 billion km away at a speed of 23,760 kph, is expected to alter the asteroid’s path.
“The spacecraft will deliberately collide with a target asteroid—which poses no threat to Earth—to change its speed and path,” stated NASA. “If successful, DART’s kinetic impact method could be used in the future if a hazardous asteroid on a collision course with Earth were ever discovered.”
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Since Dimorphos has a loose core, the post-impact shock waves and cratering process are projected to cause significantly more serious damage to the target bigger asteroid.
After the DART mission, the European Space Agency (ESA) will send its HERA mission in 2024 to investigate the aftermath of the impact with two CubeSats called Milani, the rock decoder, and Juventas, the radar visionary, to conduct a close-up crash scene examination and transmit visuals of the impact.
Chaitanya Giri, a Space Tech Consultant with Research and Information System for Developing Countries (RIS), who has studied the two asteroids for a long time, said Didymos, the bigger of the two asteroids, has “surface reflective properties that indicate it to be a stony (S-type) asteroid.”
Future of DART mission
Hence, the future of the DART mission will not end with its scheduled crash on Dimorphos on Sep 26, 2022. Scientists will have to continue monitoring the trajectory of Dimorphos for years to come. “It is not a shoot-and-forget mission,” said Giri. The Didymos asteroid will come closer to Earth again in 2042 and 2062, so the DART scientists will have to keep monitoring it.
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“There might be another DART mission, a DART-II either around 2042 or 2062, which would further deflect this potentially hazardous asteroid (PHA) from hitting the Earth. This long-range preparation shows asteroid deflection is not a knee-jerk initiative, it has to be studied well,” explained Giri to EurAsian Times.
So, the success or failure of DART cannot be assessed overnight after the collision next month but the future would reveal whether such missions help deflect such dangerous asteroids to save life on Earth.