A harmless asteroid millions of miles away has been hit by a NASA spacecraft at 14,000 miles per hour. Why? The fate of humanity may one day depend on doing the same.
Scientists say 66 million years have passed since an asteroid struck Earth and ended the reign of the dinosaurs, and they are eager to avoid a similar outcome for humans.
Sky News take a look NASA’s latest experiment – a $325m (£301m) planetary defence test – and answers some key questions about how it might prove useful in the future.
What is a dart ship?
Dart – a more snappy nickname than the Double Asteroid Redirection Test – is essentially a battering ram the size of a small vending machine.
It faces certain disruptions in achieving its goals.
Dart weighed 570 kilograms and had only one instrument: a camera to navigate, locate and record its eventual demise.
Where did the spaceship go?
Dart traveled to a pair of asteroids about 7 million miles from Earth. It targets Dimorphos, the smaller descendant of Didymos (Greek for twin).
Dimorphos is about 525 feet (160 meters) wide, and it orbits the larger Didymos in less than a mile (1.2 kilometers).
NASA insists there is zero chance of an asteroid threatening Earth — now or in the future. That’s why this pair was chosen.
The spacecraft’s navigation was designed to distinguish between the two asteroids and target the smaller one for the final 50 minutes.
What happened to the impact?
“It’s really about asteroid deflection, not destruction,” said Nancy Chabot, a planetary scientist and mission team leader at Johns Hopkins University, which is managing the work.
“It’s not going to blow up the asteroid. It’s not going to break it into a lot of pieces.”
Instead, the impact would have excavated a crater several meters in size and blasted some 2 million pounds of rock and dirt into space.
Why do scientists do this?
The impact should be enough to push the asteroid into a tighter orbit around its companion space rock — suggesting that if a killer asteroid is heading our way, we’ll have a chance to divert it.
Cameras and telescopes will observe the crash, but it will take months to determine whether it actually changed its orbit.
The observatory will track the pair of asteroids as they orbit the sun to see if Dart has altered Dimorphos’ orbit.
In 2024, a European spacecraft called Hera will retrace Dart’s journey to measure the impact.
According to Ms. Chabot, while the expected nudge should only change the position of the small satellite slightly, over time this will lead to a major shift.
“So if you’re doing this for planetary defense, you’re doing it 5, 10, 15, 20 years in advance to make this technology work,” she said.