NASA spacecraft Dart hits asteroid Dimporphos

One of the anticipated dangers from outer space is that a meteor could crash into earth, and cause mass extinction. It had happened once 65 million years ago when the dinosaurs were wiped out. There is also the fear that comets could crash into earth. But that has not happened.

It is with this scenario in mind that the United Sates’ National Aeronautics and Space Administration (NASA), which had led space exploration and succeeded in landing human beings on the moon in 1969, had launched a spacecraft Dart to hit the asteroid Dimorphos, which is orbiting a bigger one, Dydimos, which in turn is orbiting around the sun.

These asteroids were not in the way of earth’s orbit around the sun. Far from it. But NASA’s Dart is an experiment to see how much asteroids which could hit earth can be staved off. The Dart was launched in 2021, and it hit Dimoprhos in 2022 and it altered the orbit of the subsidiary asteroid by 720 metres or 2,360 feet. The Dimorphos’ orbit around the sun is 360 million miles. And the Dart hit has dented the time taken by Dimorphos by 0.15 seconds of the 769 days of the asteroid’s round trip of the sun.

But it took four years to detect the success of Dart. It is only now that reports from all over the world have come in to record the effect of the Dart hit of Dimorphos.

This is a page from science fiction, of saving the earth from celestial catastrophe. In the early 1980s, Ronald Reagan, in his first term, toyed with the idea of Star Wars, which was the Strategic Defence Initiative (SDI) to intercept the Soviet Union’s nuclear missiles through a laser shield in space. It did not take off.

Then some experts argued that this could be used to deflect space entities travelling past the earth – comets and asteroids – before they enter the earth’s atmosphere. The crash had doubled the momentum of both Dart and Dimorphos, say experts. It is estimated that 35 million pounds of rock and dust have been ejected from the asteroid because of the asteroid-spacecraft crash. Steven Chesley of NASA’s Jet Propulsion Laboratory says, “While it is just a single experiment, it is nonetheless an important data point that will be relevant to any future asteroid deflection missions.”

NASA and others expect to learn when European Space Agency’s (ESA) spacecraft Hera is launched later this year and reaches the asteroids when it will get more information about the effects of the Dart-Dimorphos crash. The asteroids are small objects in comparison to planets and comets. The threat posed by asteroids remains real. James Webb Space Telescope identified asteroid 2024 YR, which seemed headed for earth. But it became clear after observation and calculation that asteroid 2024 YR will not hit earth, but it could crash into the moon in 2032. Latest information shows that the asteroid will miss the moon by 13,200 miles.

Asteroid 2024 YR is 200 feet wide. Dydimos is 2,50 feet or 780 metres wide, while Dimorphos spans 160 metres or 525 feet. Rahil Makhadia of the University of Illinois Urbana-Champaign, who is lead author of the research piece about Dart and Dimorphos said, “Even though this looks small, a tiny deflection...can add up over decades and make the difference between a potentially hazardous asteroid hitting or missing the Earth in the future.” Asteroids are aplenty in the inter-planetary spaces, and they are hurling aimlessly across the vast and open area of the solar system. And any of them can be hurling towards the earth. So spacecraft, or interceptor missiles, to protect the earth becomes a function of space exploration.