An asteroid that fell to Earth about 65 million years ago destroyed dinosaurs and most of the life on the planet. Being intelligent and to some extent technologically advanced creatures, people began to think about how to avoid such a fate.
In the early stages of formation, the Earth was literally continuously showered with asteroids and various space debris. Today, material from outer space continues to fall on our planet, but already in the form of microscopic particles of cosmic dust. Fortunately, large asteroids rarely fall to Earth. But sometimes it still happens. It is worth remembering the Chelyabinsk meteorite that exploded over the city in February 2013. It entered the atmosphere 60 times faster than the speed of sound. It is assumed that when entering the dense layers of the atmosphere, this body was about 20 meters across, and weighed 13 thousand tons. This is not much, but enough to injure about two thousand people and damage 20 thousand buildings.
And again, fortunately for us, larger collisions are extremely rare - on the scale of human understanding. The most famous of these major collisions is the 10-kilometer object that appears to have made dinosaurs extinct 65 million years ago. But what would happen if a danger of this level and magnitude threatened us today?
NASA is working to register near-Earth objects that can fly into the inner solar system. The agency is focused on identifying bodies more than one kilometer across that could pose a threat to Earth. In July 1999, asteroid 1999 NC43 was sighted with a diameter of 2.2 kilometers. It is considered a possible source of the Chelyabinsk meteorite. In the next 150 years, this asteroid will not come close to Earth and, in fact, does not pose any danger. But if we found that one of these bodies is definitely "aimed" at collision with our planet - are we ready to prevent such a catastrophe?
Fragment of the Chelyabinsk meteorite.
This may upset science fiction fans, but for now we cannot destroy the asteroid unless it is very small in size. An easier way to deal with a meteor is to change its trajectory so that it flies past the Earth. This idea seems obvious, not very expensive, and doesn't take a long time to implement. However, the problem with this method is that the object remains in space and after some time may return, posing a new threat to all life on the planet.
So what are our options? First, we have methods available that include direct contact with an object, such as a nuclear strike, controlled collisions, attached missiles, and electromagnetic catapults. Plus there are methods that do not require direct contact, such as ion beams, solar energy and gravitational influence. All of the above represent unfinished ideas, but we will cover each of them.
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Nuclear strike
A nuclear explosion can be used in a variety of ways. First, it can blast material with enough power to slightly alter the angular momentum of an object. Bombs can also be placed close to an object - not close enough to damage it, but close enough to change its trajectory.
Controlled collisions
When an asteroid approaches Earth, you can use some of the working satellites, spacecraft, or even a specially designed probe to collide with a rocky body flying towards the planet. This is also called a non-nuclear kinetic ram. Perhaps this is one of the most appropriate solutions, speaking of the impact on an asteroid. Moreover, the European Space Agency intends to send an Asteroid Impact and Deflection Assessment (AIDA) mission to the double asteroid Didyme in 2023 to demonstrate this technology.
AIDA mission infographics.
Attaching rocket motors
Perhaps one of the least effective solutions is to attach rocket motors to the body and thus move it away from the Earth. The asteroid will fly at a very high speed, so getting to the same speed with it and then landing on it will require very high synchronization and accurate calculations. Secondly, asteroids rotate in the same way as planets and stars, so it will be incredibly difficult to direct the accelerators in any particular direction.
Electromagnetic catapult
With the help of an electromagnetic catapult, material can be gradually removed from an asteroid and thrown into outer space. Ideally, this technology will gradually provide an opportunity to change the direction of the body. It has also been suggested that this method is best implemented on the Moon, where an electromagnetic catapult will use an "unlimited" supply of material as "rock projectiles" to change the direction of the asteroid.
Ion beams
A small spacecraft can be placed near the asteroid, which will continuously shoot ion beams at it. The impact will be low, so if this technology is used, it is necessary to prepare and start work in advance. The advantage of such a device is its small size and lightness.
The principle of the ion beam to change the trajectory of an asteroid.
Solar energy
This technology is somewhat similar to an ion beam. A station with mirrors and lenses must be located near the Sun, which can focus light on the asteroid. The idea is that concentrated sunlight can have enough effect for the asteroid to change its trajectory as material evaporates from its surface.
Gravity tug
Using gravity to deflect an asteroid is probably one of the most interesting and ambitious ways. So, it will be necessary to place a large, heavy and dense apparatus very close to the asteroid. In theory, a weak gravitational effect between the two bodies will gradually change the trajectory of the asteroid, which will follow the unmanned vehicle to a zone safe for the Earth. It will take years of work, not counting the time required to create such a device.
The geometry of the gravity tug.
Of course, as Earth technology advances, we may have more options to tackle this problem. Perhaps we can develop more advanced methods of intercepting these deadly space boulders. If the human race lives long enough on Earth, it is almost inevitable that one day we will learn about a huge asteroid rushing straight towards our planet.
Vladimir Guillen