The collision of our planet with an asteroid with a diameter of 300 meters is comparable to the explosion of the atomic bomb, writes Hvilya.
In this respect, NASA announced the development of a new system of planetary protection: scientists propose to reduce the asteroid Taran, changing its trajectory. Talk about the fact that the Earth is actually vulnerable to possible asteroid threat, raised for a long time.
Someone says that the danger is greatly exaggerated, because only in 2016, the first 200 years of the death of a man from impact of a meteorite, which, however, denied at NASA, and someone that we still can’t predict the fall of celestial bodies on the Earth’s surface.
Confirmation — the famous Chelyabinsk meteorite, which caused a lot of noise and brought great losses. And we can not only predict, but even more so to prevent.
In the framework of solving the first problem, scientists consider it necessary to introduce a new Observatory as a cosmic and ground. One example is the Mobile astronomical system of telescope-robots (MASTER) created on the basis of the Moscow state University.
The main goal of the project is to obtain the relevant information of the entire visible sky for one night. In addition to searching for dark matter, new exoplanets and discoveries of small Solar system bodies, the data will help track potentially dangerous asteroids heading for the planet.
NASA also has its own Observatory, aimed at detecting potentially hazardous objects for the Earth. One of the main of these centers is considered, the Arecibo Observatory (Arecibo), located in Puerto Rico, at a height of 497 meters above sea level, and having one of the world’s largest radio telescopes, using only one aperture.
However, none of the radars did not have sufficient power to cover such a vast space, even relatively close to the Earth and the return signal for detecting unknown near-earth objects.
With the help of optical telescopes are easier to detect the light from the Sun that is reflected by the object, and ground radar can be used to more accurately track and determine the orbits of objects detected by these telescopes, their physical characteristics and dynamics of the body during the approach to Land.
The Threat Of Apophis
Radar observations are unable to adjust our data on the position of the asteroid with several thousand kilometers provided by optical observations, up to several meters.
Risk of exposure created a potentially dangerous asteroid can be relatively quickly resolved by using the radar observations, while using only optical observations, we may not be aware of his position for many years.
This was the case of asteroid (99942) Apophis, which was discovered in 2004.
Originally, in April of 2029, in which he could collide with Earth, but radar observations by the Arecibo Observatory in 2005, to practically exclude such a possibility.
After the asteroid 9 Jan 2013 closer to Earth at a distance of about 14.5 million kilometers, which is less than a tenth of the distance to the Sun, scientists have found that the volume and mass of this asteroid is 75 percent more than expected.
Studies show that the best way to defend against an asteroid, changing its trajectory depends on the particular scenario.
The choice of method of mitigation depends on the orbit of the object, its composition, relative velocity, and the probability of exposure and the intended point of impact. Some near-earth objects can have such an orbit, which is very difficult to work with, if you do not detect them for several decades.
Other asteroids — in fact, the accumulation of small fragments, which is difficult to correct the trajectory without destroying them. Some objects are too small or fragile to reach the Earth’s surface: as, for example, a meteor disintegrated over Chelyabinsk in 2013. They require a rather rapid response to emergencies.
Therefore, each case requires a special measure of planetary protection.
Planetary protection is the term used by astronomers to describe all of the capabilities needed for detection and warning of possible collisions of asteroids or comets with the Earth, and either to prevent them or mitigate the consequences.
It is necessary to accurately characterize these objects, defining the trajectory of their orbits, size, shape, mass, composition, dynamics, rotation and other parameters. These data will help the specialists to determine the severity of potential impacts.
Projects active influence on potentially dangerous asteroids that could advance to minimize the damage from their shot, all a little more complicated.
Offered different ideas: to send to the asteroid compact nuclear or conventional chemical charge with a view to its destruction, to use the gravitational tugs and rocket engines, able to deflect the course of the asteroid away from Earth.
However, most of these ideas have not yet gone further theoretical developments: these projects are too expensive and have quite a lot of controversial issues — down to the unsettled question of the use of nuclear explosives in outer space.
However, NASA came up with another method of active influence on the Earth threatening object.
We are talking about a space mission Double Asteroid Redirection Test (DART) is the first real attempt to actively affect the asteroid. The goal is to develop ways to protect the planet from impacts of objects from space.
The project is created in conjunction with the applied physics Laboratory of Johns Hopkins University with support from NASA centers: the jet propulsion Laboratory (JPL), space flight Center Goddard (GSFC) and’s Johnson Space center (JSC).
“We have a lot of scientific missions, aimed at understanding the past of the Solar system and its formation. Project planetary protection also applies to this Solar system and our closest immediate plans and actions. To implement the plan and physically to correct the trajectory of the object, you will need a lot of time to spare. The idea of kinetic RAM — of course, not what is shown in the movie “Armageddon”, where people are alarmed at the last moment and saved the Earth. We will need to take care of it for 10 or even 20 years before the impact: slightly push the asteroid so that it safely flew past and missed the planet,” explains planetary scientist Nancy Chabot (Nancy Chabot) from the applied physics Laboratory of Johns Hopkins University.
The mission of the DART selected the binary system of the asteroid, which received the name of (65803) Didymos, which in Greek means “twin”. Didymos A size of 780 meters, and its “younger brother” Didymos B is just 160 metres away. He will be the main purpose of the mission. System Didymos carefully studied since 2003: primary body is a rocky object S-type, whose composition is similar to composition of many asteroids, and the composition of the Didymos B is not yet known.
He double asteroid poses no danger to Earth: in 2003, he flew a distance of more than seven million kilometers and will approach our planet in the year 2123.
However, this mission will help scientists to get vital information that will be invaluable in the future for the protection from dangerous objects.
Knock down and trace
Preparations for the launch of space Shuttle DART will start at the end of December 2020 and will last until may 2021. The launch will be held in June 2022, and in early October, the RAM space will collide with an object at a distance of 11 million kilometers from Earth.
It is assumed that DART uses onboard Autonomous targeting system to target Didymos B, and then dug into the asteroid at the speed of six kilometers per second — about nine times faster than a bullet.
Ground-based Observatory will be able to document this impact and change the orbit Didymos B, which will allow scientists to better determine the capabilities of a kinetic impact as a strategy to mitigate the asteroids.
The technique of kinetic impact does changing the speed of a threatening asteroid a small fraction of its total speed, but doing it long before the predicted impact to this small boost over time are summarized with large displacement trajectory of the asteroid. An important part of the mission is the observation of the asteroid both before and after impact. To follow him is a small satellite, Cubesat Italian Light, which the Italian space Agency will launch simultaneously with DART. European mission Hera, in turn, will reach double by 2026 asteroid-mu and record the size and characteristics of destruction, which made the DART.
Despite the fact that Didymos does not threaten our planet, humanity should learn how to prevent collisions with potentially hazardous celestial bodies, because if we’re going to live on the Land, caring about the environment and the conservation of its resources, we need to think about the external threats that can suddenly put an end to all living things.