It is logical that NASA and ESE alter the danger forecasts of asteroid 2024 YR4, which passes from the highest percentage for an asteroid of its type to one barely threat in a matter of hours. As we have more data about its size and composition, more precise are the forecasts. But taking into account that there is an impact possibility, It is convenient to review the techniques that the main spatial agencies of the planet consider when “facing danger”
The first one would be the crash or kinetic impactor and its principle is simple: to crash an object against an asteroid in the hope that the impact will change its trajectory. The kinetic impactor is The only planetary defense technique that has been tested in a real asteroid. Dart, NASA double asteroid redirection tests, intentionally crashed into the Moon of the Dimorphos asteroid in 2022. The clash altered the orbit of Dimorphos around the asteroid Father Didymos. A cubesat deployed before the impact, as well as the Hubble space telescope, the JWST and even terrestrial telescopes, observed material that flowed from Dimorphos to space. The thrust on dimorphos of these debris that escaped was stronger than the thrust of Dart’s own impact, an important finding of the mission.
The second option is more “bucolic or country” and is a gravity tractor. Basically, a spacecraft that would fly next to an asteroid, using its own gravity to pull the asteroid and slowly change its trajectory. While it is true that The mass difference between an asteroid and a spacecraft is hugeit is a strategy that is carried out over time (years) and is based on diverting, even if it is a degree, the trajectory, which is equivalent to tens of thousands of kilometers.
In the positive section, it is an option that offers the greatest control to redirect an asteroid. The disadvantage is that this technique may not work in asteroids of more than 500 meters in diameter.
Another possible direct attack option is the use of laser: one or more ships focus on the surface of an asteroid, vaporizing the rock and creating small ejection columns. These columns push the asteroid, slowly changing their course. A variation of this technique is Solar ablation: instead of lasers, mirrors are used to direct sunlight to the surface of the asteroid.
One of the simplest is that of ion rays: redirecting the path of the object using the propeller of the Espacia ship. Space missions have been using ionic propulsion for decades, from Deep Space 1 to Dawn and Dart. Ion engines do not have a thrust as high as conventional spacecraft engines, but they can work continuously for long periods of time, and eventually boost a spacecraft at higher speeds. The goal is to give it a little push to take it to another place.
And, finally, we have the Armageddon option, the nuclear explosion. The technique is quite obvious and descriptive: a spacecraft loaded with nuclear weapons against an asteroid in an attempt to divert it away from the earth. In addition to the dangers inherent in the launch of a nuclear weapon in spacethe asteroid could break into multiple large pieces, turning a devastating asteroid impact into multiple devastating impacts. However, it could be our best option in case of planetary emergency. A Recent study It shows that a nuclear pump detonated near an asteroid 100 meters wide, at least two months before impact, It could explode 99.9% of the asteroid mass outside the Earth’s path.