Researchers Say We Have The Tech To Save Earth From A ‘Don’t Look Up’ Doomsday Event
DART launched from Vandenberg Space Force Base in California on November 24, 2021. The spacecraft is currently speeding towards a collision with asteroid Dimorphos, which will be approximately 6.8 million miles (11 million kilometers) from Earth at impact. The thought behind the mission is that, if Earth were ever presented with an Armageddon type event from a celestial impact, a spacecraft could be launched in order to collide with the object and essentially deflect it from impacting Earth. However, other researchers are not waiting for the results of that mission. A group of researchers from the University of California Santa Barbara, believe we already have all we need to divert disaster.
Researchers discuss the potential of utilizing existing technology, combined with soon-to-be-realized heavy launch assets, in order to mitigate the threat of an approximate 10 km object that is detected 6 months prior to impact. The paper mentions that a threat of this significance impacting Earth at a closing speed of 40 km/s, would have an impact energy of approximately 300 Teratons of TNT. This type of energy would be 40 thousand times larger than all of the current nuclear arsenal of the entire world combined. An event of this magnitude would be similar to the event that killed the dinosaurs some 66 million years ago.
The paper, posted on Arxiv this past week, mentions an event that occurred over Chelyabinsk, Russia on February 15, 2013 as an example to the continual threat asteroids and comets present to life on Earth. That event produced a total energy of about 0.5 Mt, or about that of a modern ICBM thermonuclear warhead. Approximately 50% of its energy was released into an atmospheric blast wave that injured about 1,600 people. On the same day that event occurred, another 50 m diameter asteroid (2012 DA 14) passed within the geosynchronous satellite belt. If that asteroid had made impact, it would have yielded about 10 Mt. An impact of that nature over a major city could have killed and injured millions of people. Asteroids that are around 50 m in diameter are expected to strike Earth approximately every 650 years.
Philip Lubin and Alex Cohen, researchers at the University of California Santa Barbara, state in their paper, "We show that humanity has crossed a technological threshold to prevent us from 'going the way of the dinosaurs'. We show that mitigation is conceivable using existing technology, even with the short time scale of 6 months warning."
Lubin and Cohen believe that the most effective method of fragmenting an asteroid is using small nuclear explosive devices (NED) embedded in the space craft's penetrators. This, along with soon-to-be-realized heavy lift launch assets such as the SpaceX Starship, is sufficient to mitigate this type of existential threat. While a method such as this would not completely annihilate an asteroid, it would vaporize part of the asteroid's surface, and in turn generate an explosive thrust and a change in velocity and trajectory in response. This would be similar to what NASA's DART mission is attempting, in that it would hopefully divert it from hitting Earth.
In order to have the time to prepare for an attempt of this nature, the duo believe we would need at least a 6 month warning. As an example, a threat from an asteroid 10 km in diameter traveling at 40 km/s would require a launch time of the interceptor spacecraft 5 months prior to impact. This would place impact one month prior to impact with Earth, pushing fragments from the asteroid off a collision course.
The duo even take a light-hearted poke at what would be needed if an asteroid the size of Texas, approximately 830 km diameter, posed a threat. In a though experiment, the two stated, "What do you do now? You are going to need some die hard to get you out of this one. A couple of options: a)party, b) move to Mars or the Moon to party, c) do what they did in Chicken Run during take-off." All joking aside, Lubin and Cohen stated that the purpose of their paper was to show that even with a short-term warning scenario, we have the ability to respond, but only if we prepare.
“Though the numbers may seem daunting, it is not outside the realm of possibility even at this point in human technological development,” Lubin and Cohen said. “This gives us hope that a robust planetary defense system is possible for even short notice existential threats such as we have outlined. Ideally, we would never be in this situation, but better ready than dead.”