NASA testing planetary defence spacecraft to divert asteroid's path
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Last week, a lonely SpaceX rocket blasted off from California with NASA’s ambitious Double Asteroid Redirection Test (DART). The first-of-its-kind mission will rendezvous with a duo of asteroids next year, called Didymos and Dimorphos, to test the Earth’s best – and likely only – means of preventing a devastating impact. But rather than attempting to blow the asteroids to smithereens, the DART spacecraft will instead ram the smaller Dimorphos in an attempt to alter its orbit.
Because although Hollywood blockbusters Armageddon (1998) and Deep Impact (1998) have produced breathtaking scenes of asteroids being blown up with nukes, scientists have warned such a course of action is virtually out of the question.
According to John Womersley at the University of Oxford, blowing up a large asteroid flying at Earth would only turn it into hundreds if not thousands of smaller objects about to strike.
The expert likened it to being hit with a “shotgun blast” – and the potential damage could be even greater.
This was evident in the nail-biting finale of Deep Impact when an effort to blow up a comet only ended up in it being split in two.
The fictional result? Hundreds of millions of deaths across Europe, Africa and North America.
Professor Womersley told Express.co.uk: “Blowing up an asteroid makes a great movie effect, but would be really stupid in real life.
“Instead of one big rock heading towards Earth, you’d just create a huge number of smaller rocks heading the same way, like a shotgun blast, with the potential to do even more damage.
“This is the best approach; a small kick to an asteroid’s trajectory far before it gets close to Earth is all that would be needed.”
Luckily for life on Earth, scientists are not aware of any asteroid or comet that poses any threat to the planet now or in the next few hundred years.
NASA reveal what you need to know about asteroids
And the target of NASA’s DART, Didymos and Dimorphos, was selected because its the perfect candidate for the proof of concept test.
But deadly asteroid impacts have happened in the past and small space rocks constantly pelt the planet.
Lindley Johnson, planetary defence officer at NASA Headquarters, said: “We have not yet found any significant asteroid impact threat to Earth, but we continue to search for that sizable population we know is still to be found.
“Our goal is to find any possible impact, years to decades in advance, so it can be deflected with a capability like DART that is possible with the technology we currently have.
“DART is one aspect of NASA’s work to prepare Earth should we ever be faced with an asteroid hazard.”
When a six mile-wide (10km) asteroid struck just off the coast of modern-day Mexico 66 million years ago, the resulting fallout contributed to the extinction of the dinosaurs and approximately 75 percent of all life on Earth.
But even smaller impacts can sow chaos and confusion.
When a 65ft-wide (20m) exploded in the skies over Russia’s Chelyabinsk Oblast in 2013, the airblast blew out windows in a wide radius and injured more than 1,500 people with shards of glass.
Professor Womersley said: “NASA estimates that only a small fraction of the large objects that might one day strike the earth have yet been tracked, and more are being discovered all the time.
“We know impacts don’t happen very often, but we know that they do happen, and that they have the potential to do great damage.”
The planet may be safe for now and the foreseeable future but scientists have praised NASA’s attempt to get ahead of the curve and bolster Earth’s defences.
Following DART’s launch on November 24, Professor Brian Cox tweeted: “This is great news – successful launch of #Dartmission – one day, when we need to deflect an asteroid on a potential collision course with Earth, we’ll remember this as a major step towards that capability.”
Neil deGrasse Tyson, astrophysicist and author, called the mission a “badass move” and praised the scientists involved who have made it possible.
And Bill Nye ‘The Science Guy’ told MSNBC of the £248million ($330million) mission: “This is a very inexpensive test of what one day may be a planet-saving technology.”
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