Is it possible to dodge an asteroid threatening the Earth, has humanity learned from the impact of the Chelyabinsk meteorite and is NASA's future mission capable of protecting the planet?
The fall of the "meteorite", which caused the collapse of the hill and the complete blocking of the Bureya River, for several days in December became the number one news in the Russian media, causing excitement, interest of scientists and worries about the operation of the Bureyskaya hydroelectric power station.
However, after a short time, the meteorite turned out to be only a landslide, and the whole story is a vivid example, albeit not intentionally, but fake news. After all, the first meteorite version was put forward not by scientists and not even by journalists, but by hunters and representatives of the local administration, who for all their professionalism are not specialists in meteorites.
Nevertheless, on the first day, the news of the meteorite made a splash and made you imagine a giant fireball, whose body blew up the hill and caused a local cataclysm. The memory of the Tunguska meteorite and the memories of February 2013, when the famous Chelyabinsk meteorite caused a lot of trouble, are still too alive, at least in Russia.
Then, as a result of the strike, more than a thousand residents of the Chelyabinsk region were injured, and industrial and residential buildings suffered great damage, which, according to some estimates, exceeded one billion rubles.
After the fall of the Chelyabinsk meteorite, a noise arose in the press about the need for a system to prevent the collision of the Earth with such bodies. Hearings with invited experts were held in the government and the Federation Council, and Deputy Prime Minister Dmitry Rogozin then presented proposals “on the country's promising capabilities to“detect”the danger of the Earth coming closer to“aliens”and prevent it in the future.
Discussions about the Earth's defenselessness in front of the asteroid hazard have arisen constantly and for more than one decade. On the one hand, until recently it was believed that the asteroid hazard was greatly exaggerated, and only in 2016 was the first case of human death from a falling meteorite officially recorded.
On the other hand, the facts, and first of all the fall of the Chelyabinsk meteorite, indicate that with all technological progress, with an increase in the number of discovered near-Earth asteroids, mankind still cannot even confidently predict the fall of such bodies, especially those flying from the direction of the Sun.
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Not to mention taking proactive steps ahead of time to minimize damage from their fall to Earth.
As for the solution of the first problem, scientists are calling for a focus on the commissioning of new observatories, space and ground, for earlier warning of approaching asteroids. One of such systems, for example, could be the Russian Robotic Observatory MASTER, the head of which, professor of Moscow State University, astronomer Vladimir Lipunov, in 2013 from all tribunes called for attention to this problem after the incident in Chelyabinsk.
This work is not meaningless. In 2009, the journal Nature described for the first time the case of the discovery of an asteroid before it entered the Earth's atmosphere, predicted the place and time of the fall, and its fragments were indeed discovered later in the Nubian Desert.
It is much more difficult with projects of active impact on potentially dangerous asteroids, which could have minimized the damage from their impact in advance. These ideas have been hovering for a long time: sending a compact nuclear or traditional chemical charge to an asteroid in order to destroy it, using a gravitational tug, rocket or ion engines capable of deflecting the asteroid from the Earth.
However, most of these projects are still only on paper - it will be too expensive to implement them in advance and too many uncertainties arise - the same issue of unsettled use of nuclear charges in outer space.
The first real attempt to train in active impact on dangerous asteroids will be an unusual NASA space mission, the details of which are currently being worked out - Double Asteroid Redirection Test (DART).
Unlike other missions to space bodies, its task will not be to collect scientific data that shed light on the structure and origin of the solar system.
Its purpose is utilitarian - working out ways to protect the planet from a blow from space.
“The big difference is that we have many scientific missions aimed at understanding the past and formation of the solar system,” planetary scientist Nancy Chabot of the Applied Physics Laboratory of Johns Hopkins University told the recent American Geophysical Union meeting. "Planetary protection - this really refers to the present solar system and what we are going to do in the present."
The target of the DART mission was the asteroid (65803) Didyma, a small, rapidly rotating near-Earth asteroid from the Apollo group, whose orbit crosses the orbit of not only Earth, but also Mars.
This asteroid is very large, its size is about 800 meters. But the main feature is the presence of a small satellite with a diameter of only about 150 meters. It is these asteroids, while remaining difficult to detect, according to scientists, pose the greatest threat to the Earth. This satellite attracted the attention of scientists as a possible target for the development of the so-called kinetic ram, capable of protecting the planet in the future.
The binary asteroid itself does not threaten Earth, but the experiment will help in collecting data that will allow it to be used in the future to protect it.
If everything goes according to plan and the mission is launched in June 2021, the first man-made mini-disaster will be created in space in October 2022, when a sent messenger from Earth hits an asteroid at a speed of about six kilometers per second.
It is estimated that the impact will occur 11 million kilometers from Earth and cause a deviation of the small body's orbit, which can be seen with instruments.
An important part of the mission will be to observe the asteroid both before and after the impact. For example, the asteroid will be followed by a small Light Italian Cubesat, which the Italian space agency plans to launch together with DART. Another European mission, Hera, will have to reach the asteroid in 2026 to see the size and features of the crater and the destruction caused by earthlings.
According to Chabot, the members of the mission are encouraged by the possibility of such an experiment, but for the real protection of the Earth from a similar threat, the earthlings must have a lot of time.
“It will take us a lot of time to do something like this. The idea of a kinetic ram is definitely not what is going on in the movie "Armageddon", where people were alarmed at the last hour and saved the Earth, - she explained. "This is something that will have to be done 5, 10 or 20 years before the impact - to push the asteroid slightly so that it quietly flies by and does not hit the Earth."