Scientists from NASA, an American space agency, burst into applause and shouts of joy on Monday afternoon when the DART mission, a ship launched in November 2021hit a meteor located about 11 million kilometers from Earth.
With this action, the United States wanted this Monday to demonstrate that it plans to seize the planetary defense.
Although they assure that with current technology, attacking it to try to divert the trajectory of an asteroid with the impact of a spacecraft is for the moment the only way to defend the Earth from an approaching object, scientists have also thought of other ideas, to more of the DART mission, as a way to defend the Earth.
Russian scientists, in a 2018 article published in the “Journal of Experimental and Theoretical Physics”, analyzed the scenario of a direct detonation. They built miniature models of asteroids and fired lasers at them. They showed that blowing up a 200-meter asteroid would require a bomb 200 times more powerful than the one that exploded over Hiroshima in 1945.
Other proposed ideas include a “gravity tractor” or a mission to blow up the hypothetical object with a nuclear weapon, the method favored by Hollywood.
This technique is the one that NASA experimented with this Monday. Consists in crash into an asteroid with a shipin order to “push” it slightly, and thus divert its trajectory.
This first test will allow us to understand how the asteroid reacts and, therefore, better calculate the necessary force in the future.
If the threat of an asteroid impact on Earth were real, a mission would have to be launched a year or two in advance to deal with a small asteroid, or decades before the projected impact for objects hundreds of kilometers across.
A larger object could require the impact of multiple spacecraft.
If an object’s approach is detected years or decades before it hits Earth, a spacecraft could be sent to fly alongside it long enough to deflect its trajectory with a gravitational pull on the part of the spacecraft, creating a “gravity tractor”.
“The virtue” of this method is its “totally good understanding” because “we know how gravity works,” DART program scientist Tom Statler said at a November briefing.
However, the mass of the spacecraft would be a limiting factor, and gravity tractors would be less effective for asteroids larger than 500 meters in diameter, which are precisely the ones that pose the greatest threat.
In a 2017 paper, NASA engineers proposed that the spacecraft extract material from the asteroid to enhance its own mass, and thus gravity.
But none of these concepts have been proven and it would take decades to build, test and launch.
Another option is to drop nuclear bombs to redirect or destroy the asteroid.
But atomic weapons are controversial and are prohibited for use in outer space, although according to an article published by NASA, the explosion could serve as a “last resort” in case other methods fail.
Lori Glaze, director of NASA’s planetary science division, said in 2021 that the agency believed the best way to deploy the weapons would be some distance from the asteroid to impart force to the object without blowing it up into smaller pieces that could then be destroyed. multiply the threat to Earth. (YO)