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Chinese missile of the "Long March 5" type
Photo: VCG / Getty Images
It is not that the collisions of mighty chunks from space with the earth are pure science fiction.
There are plenty of examples of asteroid impacts, as the partly scarred surface of the earth shows.
Think of the mighty Chicxulub crater, which heralded the end of the dinosaurs 66 million years ago and caused mass extinction.
Or the Chelyabinsk meteorite, which was relatively small at 20 meters, but in 2013, when its individual parts pelted the earth, still developed powerful explosive power.
When Hollywood deals with the subject, as in the disaster shocker "Armageddon" with Bruce Willis, it is always US heroes who save the world.
But maybe in the end it is people from other parts of the world who are successful with the necessary technology.
China has now taken on the topic and hopes to counter the danger of asteroids on earth collision course with rocket technology.
In order to change the course of such a chunk decisively, the emerging space nation wants to send off almost two dozen of the largest rockets in the country.
At the National Space Science Center, headquartered in Beijing, researchers have shown in simulations that the impact of 23 "Long March 5" rockets on an asteroid about 1.4 times the radius of the earth and of a certain size, might be enough to distract it from its original path.
The Chinese experts did not look at a fictitious pile of stones, but rather an old friend, the asteroid Bennu, which NASA has already visited with its "Osiris-Rex" probe.
The celestial body, which is more than 4.5 billion years old, is relatively close to the earth, rich in carbon and has a diameter of around 500 meters.
The deep black lump is also included on a list of potentially dangerous asteroids because it will come quite close to Earth in more than 150 years - even if the impact risk has so far been considered to be very low.
So far, more theory than practice
The "Long March 5" launch vehicles are seen as the future of Chinese space travel.
In the future, they will take on many tasks, from transporting modules for China's space station to launching probes to the moon and Mars.
The nation has successfully launched six of these missiles since 2016, with the last missile causing some safety concerns when its remains fell back to Earth in May.
"The proposal to turn the upper stage of the launcher into a lead rocket to deflect an asteroid is a pretty nice concept," said Alan Fitzsimmons of the Astrophysics Research Center at Queen's University Belfast about the Chinese idea. Researchers are currently assuming that the use of such a so-called kinetic impactor, which knocks the approaching boulder off the track like a billiard ball, is the only chance. By increasing the mass that hits the asteroid, the physics of China's rockets should provide such an effect, Fitzsimmons said. However, the practical implementation of such a mission must be planned more precisely. So far it is apparently only a theoretical approach by the Chinese.
According to Gareth Collins of Imperial College London, according to current estimates, there is a roughly one percent chance that a hundred-meter-wide asteroid will hit Earth in the next hundred years. A lump the size of Bennus is about ten times less likely. Asteroids with a size of more than one kilometer would already have global consequences for our planet. After all, around 150 new asteroids are discovered near our planet every month, and the total number of these so-called Near Earth Objects (NEOs) is around 20,000. Especially the smaller ones could be dangerous if they are overlooked.
Blasting the chunks with, for example, nuclear warheads does not seem to be a suitable means.
Because the chunk may be broken up into individual fragments, which nevertheless do not change their path.
Other space agencies are also working on strategies to ward off asteroids on a collision course.
NASA plans to use a space probe to intercept two asteroids relatively close to Earth by 2022 at the latest.
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 mankind's first attempt to change the orbit of a celestial body.
joe / Reuters
