DART: first planetary defense test against an asteroid – opinion

A sunny day in the future. Suddenly, the warning lights go on at NASA’s Mission Control Center. A telescope that scans the motion of near-Earth objects has recognized that an asteroid a few kilometers across is on a collision course with Earth. The calculation of its orbit around the sun determines that the impact will occur in a few decades and will cause devastating destruction around the world. Humanity faces a real threat to its existence. what do we do? Are we doomed or do we have a chance to prevent the apocalypse?

Today, no known large asteroid in the solar system poses a danger to Earth or parts of it. However, many more asteroids that we know nothing about and that could potentially endanger us are relatively close to us in space. Throughout history, planet Earth has experienced its fair share of destructive impacts, and more collisions will inevitably occur in the future, unless we can prevent them. Much evidence of these events can be seen in the scarred face of the moon, in the impact craters here on Earth, as well as in the large impact of an asteroid that is presumed to have played a role in the famous extinction event. massive that led to the disappearance of the dinosaurs.

The Earth is bombarded daily from space by more than 100 tons of particles smaller than a grain of sand, which burn up in the atmosphere. About once a year, a car-sized asteroid hits Earth, leaving an impressive fireball as it burns through the atmosphere. Larger asteroids hit Earth less often. An asteroid the size of a soccer field can cause considerable and widespread damage, but it hits Earth every few thousand years on average, while a collision with an asteroid a few kilometers in diameter, such as the one presumed to have caused the extinction of the dinosaurs. , is a very rare event that occurs only once every several million years. According to the late physicist Steven Hawking, the impact of an asteroid is one of the greatest threats to the future of intelligent life in our world.

Planetary defense system

The planned asteroid defense system is designed to work in a similar way to the way missile defense systems like the Iron Dome work. The Iron Dome uses radars to detect a rocket launch and then calculates its trajectory and determines whether it poses a threat to a populated area or to a site that houses vital facilities. In the event that the launched rocket poses a threat, the system launches an interceptor missile at the rocket, which explodes nearby and destroys the rocket.

Similarly, the planetary defense system uses telescopes to detect asteroids, calculates their size and orbit around the sun, and determines to what extent they could endanger the Earth. Asteroids over 150 meters in diameter that pass close to Earth are being continuously monitored, in the event that the gravitational pull of another planet deflects them from orbit onto a collision course with us. The impact of an asteroid of this type when hitting the ground will release an amount of energy at least a thousand times greater than the energy released by the first atomic bomb, dropped on the city of Hiroshima, Japan.

Unlike the Iron Dome missile defense system or Hollywood movies like “Armageddon”, in which the Earth-threatening asteroid is detonated, the most realistic goal is to slow the asteroid or slightly deviate it from its orbit. making it move. miss planet earth. For the first time, NASA will conduct such an experiment, using a one-of-a-kind spacecraft, called the DART (Double Asteroid Redirection Test). About a year after launch, the spacecraft is expected to intentionally collide with its target: the asteroid Dimorphos. Dimorphos is about 160 meters in diameter and closely orbits a larger asteroid about 780 meters in diameter, called Didymos.

The DART spacecraft will play the role of the interceptor missile, with the goal of causing a slight change in the trajectory of Dimorphos and examining how similar future technology may allow us to deflect dangerous asteroids from their orbits. Similar to the interceptor missiles in the Iron Dome system, the DART spacecraft will be programmed to detect the asteroid and autonomously maneuver toward it, using new technologies that will be tested in space for the first time. This will allow it to operate at great distances from Earth, where real-time control of the spacecraft will not be possible due to limitations imposed by the speed of light.

The spacecraft will send images to Earth until the moment of impact. In addition, a small camera, carried by a secondary spacecraft that will detach from the DART prior to impact, will capture the moment of the collision from a distance, documenting the particles flying out of the asteroid and the crater that will form in it and transmitting the image. information. data directly to Earth.

After the impact, astronomers will meticulously measure the change in the asteroid’s trajectory and the European Space Agency will launch a specialized probe for a detailed post-impact study. The impact investigation will allow the asteroid’s structure to be examined and will help improve complex models of a collision between a spacecraft and an asteroid. In this way we can improve our preparedness in case we have to divert a dangerous asteroid from a collision course with Earth.

Close monitoring

In this mission, it is assumed that the collision will not change the orbit of the asteroid around the Sun, but will simply cause an orbital change in its path around the larger asteroid, without causing a deviation in its combined path. “This double asteroid system was chosen because the largest asteroid, Didymos, allows us to easily measure changes in the trajectory of the smallest asteroid, Dimorphos,” explains Dr. David Polishook, an astrophysicist at the Weizmann Institute of Science and a member of the mission science team. “The fact that this asteroid orbits a larger asteroid about twice a day will allow us to continue to monitor changes in its trajectory with greater precision. The changes can be calculated from the speed at which sunlight is reflected from the main asteroid masked by the smaller asteroid, similar to how planets outside the solar system mask some of the light that comes from the star. around which they are in orbit. “

The Israeli team will be one of the few in the world to see the collision in real time. “It will occur at a time when most of the world’s great telescopes will be in daylight, but it will be at night in Israel. Therefore, the observations made in Israel are of great importance, in order to identify the quantity and properties of the material that will be emitted by the asteroid during the collision ”, adds Polishook. “The effect of this impact on the asteroid will show us how much collision energy was used to push the asteroid, and how much was wasted, or rather was absorbed by the asteroid itself during its change of shape: the size of the crater formed in it and the amount of material that dispersed into space after the impact. This type of information is also important for larger asteroids, the kind that could cause global damage. “



Reference-www.jpost.com

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