To prevent humans from repeating the extinction of dinosaurs, NASA will launch a "cannonball" at the asteroid

And on Nov. 24, NASA will launch a mission-critical satellite. The success or failure of this mission will determine whether the fate of dinosaurs will one day be staged on humans again in the future.

A satellite the size of a car will take off from the Vanderbilt Space Force Base in California on a SpaceX Falcon 9 rocket in the early hours of Wednesday morning, U.S. time.

By the end of September and early October next year, the satellite will act as a "kinetic weapon" and collide with a set of twin asteroid systems.

The scientists' expectation is that the impact could significantly alter the orbit of the binary asteroid system. This mission has now cost more than $300 million. It will test whether humans have the ability to deflect the course of asteroids and other astronomical objects to protect Earth, humans, and other species.

On February 15, 2013, residents near Chelyabinsk, Russia experienced a once-in-a-lifetime astronomical event: a bolide entered Earth's atmosphere over the southern Ural Federal District, began to burn, and ended up in the city of Chelyabinsk Explosion above.

The meteorite is only about 17 meters in diameter and has a mass of about 7,000 tons. The explosion height is estimated to be in the range of 30-70 kilometers. It is such a small meteorite, and the air explosion shock wave caused by its air explosion effect has caused nearly 1,500 people to be injured to varying degrees. The asteroid impact event in 2013 reminded astronomers once again: it is time to start the "planetary defense plan".

The European Space Agency (ESA) and NASA had their own internal plans for defending against asteroids by impacting satellites. But the two agencies signed a cooperation agreement in 2015 called the Asteroid Impact and Deflection Assessment (AIDA).

The two agencies jointly selected the target for the impact test: the Didymos twin asteroid system

Among the two asteroids, the larger one is called Didymos (Didimos, Chinese name "Twin Star"), with a diameter of about 780 meters; ”), only about 160 meters in diameter. The twin star orbits the twin star once every 12 hours.

Selecting this group of asteroids as the test targets of the "Planetary Defense Program", astronomers probably thought like this:

First of all, even if the impact is completed, it is almost impossible for these two asteroids to collide with the earth, so they are suitable for "practice martial arts";

The mass of the twin star is very small. If you want to have a considerable impact on it, you do not need too much satellite mass, and there is a revolution relationship between the twin stars. The small star is the "satellite" of the big star, and the distance is only about 1.2 kilometers. Therefore, hitting a small star can also have a significant impact on the trajectory of the big star, achieving the effect of "four or two moving a thousand pounds".

The European Union and the United States had originally planned to launch two satellites for the mission in late 2020 and 2021, respectively. Among them, the European Union's AIM orbiter will fly around the big star, analyze the material composition of the binary star and send data back to Earth, and observe the effect of future collisions at the closest distance.

The U.S. aircraft, the DART to be launched tomorrow, the full name of Double Asteroid Redirection Test, will collide with the small star when the double star moves closer to the earth next year to deflect the orbit of the double star system.