Chinese scientists want to send more than 20 of China’s largest rockets to practice turning away a sizable asteroid in a technique that may eventually be crucial if a killer rock is on a collision course with Earth.
The idea is more than science fiction. Sometime between late 2021 and early 2022, the US will launch a robotic spacecraft to intercept two asteroids relatively close to Earth.
When it arrives a year later, the Nasa spacecraft will crash-land on the smaller of the two rocky bodies to see how much the asteroid’s trajectory changes. It will be humanity’s first try at changing the course of a celestial body.
At China’s National Space Science Center, researchers found in simulations that 23 Long March 5 rockets hitting simultaneously could deflect a large asteroid from its original path by a distance 1.4 times the Earth’s radius.
Their calculations are based on an asteroid dubbed Bennu, orbiting the sun, which is as wide as the Empire State Building is tall. It belongs to a class of rocks with the potential to cause regional or continental damage. Asteroids spanning more than 1km would have global consequences.
The science centre cited a recently published study in Icarus, a journal on planetary science.
China has successfully launched six Long March 5 rockets since 2016. They are a key element of Beijing’s space ambitions.
“The proposal to make one large ’kinetic impactor’ to deflect an asteroid, is a rather nice concept,” said Professor Alan Fitzsimmons from the Astrophysics Research Centre at Queen’s University, Belfast, Northern Ireland.
“By increasing the mass hitting the asteroid, simple physics should ensure a much greater effect,” he told Reuters, although, he added, the actual operation of such a mission needs to be studied in greater detail.
Current estimates show there is roughly a 1% chance a 100-meter-wide asteroid would strike Earth in the next 100 years, said Professor Gareth Collins of Imperial College London.
Altering an asteroid’s path presents a lower risk than blasting the rock with nuclear explosives, which may create smaller fragments without changing their course, he added.
Asteroid impact craters leave quite an impression on the surface of planets and moons.
The largest verified asteroid crater on Earth today is the Vredefort crater in South Africa.
It is more than 300km across, which means the asteroid that created it was about twice the size of the one that struck Earth and exterminated the dinosaurs.
The largest asteroid predicted to make a close approach to Earth this year zipped by from a safe distance on March 21, according to Nasa.
That relatively small near-Earth asteroid, was around 700m wide and more than five times the distance between Earth and the moon, during its closest approach, moving at 125,000kph.