How to stop an asteroid impact?


In 1908, the aerial explosion of a meteoroid crushed 80 million trees near the Podkamennaya Tunguska River (Siberia). An impact crater was never found, since, according to the story, the celestial body disintegrated at an altitude of 5 or 10 kilometers. What would have happened if the nearly 100-meter-long rock had hit the Earth’s surface? Scientist Lubin no longer wants to trust luck and has designed a planetary defense system to deal with any dangerous asteroids or comets.


spray it

University of California Santa Barbara physics professor Philip Lubin and co-investigator Alexander Cohen recently presented in the journal “Progress in Space Research” his new creation: PI, which means spray it (Spray it). Basically, it involves using technology to “pulverize” the asteroid in question into smaller debris that would then burn up in the Earth’s atmosphere.

Paradoxically, his thesis is based on the idea of that the Earth receives the impact of the celestial rock, instead of trying to divert its course as much of the scientific community has so far proposed. The difference in this case is that your system would disassemble the threat into smaller pieces, mitigating the damage it could cause. Indeed, according to their study, these large “pieces” – the size of a conventional house – would be absorbed by the energy of the atmosphere without ever touching the ground.

“In short-intercept scenarios, asteroid fragments up to 10 meters in diameter allow Earth’s atmosphere to act as a ‘beam dump’ where the fragments burn up in the atmosphere or burst into the atmosphere. ‘air, the main incoming energy channel spatially and temporally uncorrelated shock waves’explain the study.

How to explode the asteroid?

After theory comes practice. And attacking a celestial object in full motion does not seem easy… To do this, researchers have developed an “impactor” not only kinetic, but also explosive.

Thanks to a system of penetrating rods – 10 to 30 cm in diameter and two to four meters long – placed on the trajectory of the asteroid to “cut and cut” the threatening object, PI would manage to fragment the nucleus of the asteroid or comet when it collided with them at extreme speed.

The researchers explain the difference: Imagine that “A 500 kilogram piano was thrown at your head from a distance of one kilometer or 500 kilograms of foam balls fell on you from the same distance”. Bullets might do some damage, but definitely they wouldn’t kill you. His idea was rewarded with the JAR in the CANI program (Innovative Advanced Concepts), which promotes and supports visionary ideas that can transform future missions.

Just 10 days before impact

Months or years in advance, a “kinetic impactor” can be sent to redirect an asteroid. But what if this system breaks down? Or if we find out too late that an asteroid is approaching Earth? It is in this scenario that Lubin’s plan becomes vitally important. “The great advantage of this approach is that it allows terminal defense in short warning times and attenuation of the target distance. when orbital deviation is not possible”, explains Lubin.

According to his calculations, smaller targets, such as the meteor of Chelyabinsk (2013-13 injured), could be intercepted minutes before impact using smaller launchers similar to those intercontinental ballistic missile interceptors.

an asteroid like Tunguska it could be intercepted five hours before impact. While targets that pose a more serious threat, such as Apophis (it has been speculated that it could impact Earth in 2029), they could be intercepted just 10 days before impact. “Humanity has so far been spared a large-scale disaster such as our ancient planetary inhabitants suffered, but relying on ‘luck’ is a bad long-term strategy”said Philip Lubin in 2021.

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