Ten months after the launch, NASA''s asteroid-deflecting DART spacecraft made a public impact with its target on Monday, taking a look at the world''s first planetary defense system, designed to avoid a deadly collision with Earth.
The cube-shaped "impactor" vehicle, which was roughly the size of a vending machine with two rectangular solar arrays, was on course to enter the asteroid Dimorphos, which is as large as a football stadium, and self-destruct around 7pmEDT (4:30 IST), weighing 6.8 million kilometers (11 million km) from Earth.
The finale of the mission will test the capability of a spacecraft to alter an asteroid''s trajectory with sheer kinetic force, plowing into the object at high speed to nudge it astray just enough to keep our planet out of harm''s way.
It is the first attempt in the world to change the motion of an asteroid or any celestial body.
DART, which was launched by a SpaceX rocket in November 2021, has made the majority of its voyage under the guidance of NASA''s flight directors, with controls expected to be handed over to an autonomous on-board navigation system in the final hours of the voyage.
The planned impact of Monday evening will be monitored in real time from the mission operation center at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.
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DART''s celestial target is an asteroid "moonlet" roughly 560 feet (170 metres) in diameter that orbits a parent asteroid five times larger called Didymos as part of a binary pair with the same name, the Greek word for twin.
Both objects pose a real threat to Earth, and NASA scientists claim that their DART experiment can no longer create a new existential danger by mistake.
Dimorphos and Didymos are both tiny in comparison to the cataclysmic Chicxulub asteroid that impacted Earth 66 million years ago, destroying three-quarters of the world''s plant and animal species, including the dinosaurs.
According to NASA scientists and planetary defense experts, smaller asteroids are more common and pose a greater theoretical concern in the near future.
Their close proximity to Earth and its dual-asteroid configuration make them ideal for the first proof-of-concept mission of DART, short for the Double Asteroid Redirection Test.
The suicide of a robot is a crime.
The mission is a rare event in which a NASA spacecraft must ultimately crash to achieve success.
DART will travel directly into Dimorphos at 15,000 miles per hour (24,000 km) and is bumping it hard enough to shift its orbital track closer to its larger companion asteroid.
Cameras on the impactor and on a smallcase-sized mini-spacecraft that had been released from DART days in advance are designed to record the collision and send images back to Earth.
According to APL, DART''s own camera is expected to offer pictures at the rate of one image per second during its final approach, with those images streaming live on NASA TV beginning an hour before the impact.
If one is ever discovered, the DART team said it expects to shorten Dimorphos'' orbital track by 10 minutes, but would consider at least 73 seconds a success. Using a relatively small nudge to an asteroid millions of miles away might be enough to safely reroute it away from the planet.
The results of the experiment will not be disclosed until a fresh round of ground-based telescope observations of the two asteroids in October. Earlier calculations of the starting location and orbital period of Dimorphos were confirmed during a six-day observation period in July.
DART is the latest of several NASA missions to explore and interact with asteroids and primordial rocky remnants from the solar system''s formation more than 4.5 billion years ago.
Last year, NASA launched a probe on a trip to the Trojan asteroid clusters near Jupiter, while the grab-and-go spacecraft OSIRIS-REx is on its way back to Earth with a sample from the asteroid Bennu.
The Dimorphos moonlet is one of the most smallest astronomical objects to receive a permanent name and is one of the 27,500 known near-Earth asteroids of all sizes monitored by NASA. While none are known to pose a foreseeable threat to humankind, NASA estimates that many additional asteroids remain untected in the near-Earth vicinity.
The whole cost of the DART project has been raised at $330 million (approximately Rs. 2,700 crore) and is far below the cost of many of the space agency''s most ambitious science missions.
Thomson Reuters 2022