Nasa launches spacecraft aimed at asteroid
WASHINGTON: A Nasa mission to deliberately smash a spacecra into an asteroid — a test run should humanity ever need to stop a giant space rock from wiping out life on Earth — blasted off Tuesday from California.
It may sound like science fiction, but the DART (Double Asteroid Redirection Test) is a real proof-of-concept experiment, which li ed off at 10.21pm Pacific Time Tuesday (0621 GMT Wednesday) aboard a SpaceX rocket from Vandenberg Space Force Base.
The goal is to slightly alter the trajectory of Dimorphos, a ‘moonlet’ around 160 metres, or two Statues of Liberty wide that circles a much larger asteroid called Didymos (2,500 feet in diametre). The pair orbit the Sun together.
Impact should take place in the fall of 2022, when the binary asteroid system is 11 million kilometres from Earth, almost the nearest point they ever get.
“What we’re trying to learn is how to deflect a threat,” Nasa’s top scientist Thomas Zuburchen said of the US$330 million project, the first of its kind.
To be clear, the asteroids in question pose no threat to our planet. But they belong to a class of bodies known as Near-Earth Objects (NEOs), which approach within 30 million miles.
Nasa’s Planetary Defence Coordination Office is most interested in those larger than 460 feet in size, which have the potential to level entire cities or regions with many times the energy of average nuclear bombs.
There are 10,000 known nearEarth asteroids 460 feet in size or greater, but none has a significant chance to hit in the next 100 years. One major caveat: scientists think there are still 15,000 more such objects waiting to be discovered.
Planetary scientists can create miniature impacts in labs and use the results to create sophisticated models about how to divert an asteroid — but models are always inferior to real world tests.
Scientists say the DidymosDimorphos system is an ‘ideal natural laboratory’, because Earth-based telescopes can easily measure the brightness variation of the pair and judge the time it takes the moonlet to orbit its big brother. Since the current orbit period is known, the change will reveal the effect of the impact, scheduled to occur between Sept 26 and Oct 1, 2022.