How NASA will practice saving the world from an asteroid apocalypse
NASA launched the Double Asteroid Redirection Test (DART) mission on a SpaceX Falcon 9 from Vandenburg Air Force Base in California on Nov. 24. Next fall, DART will move into the vicinity of the asteroid Didymos and its tiny moonlet Dimorphos. Although it does not pose a danger now, it serves as an opportunity: The probe will smash into Dimorphos, increasing the time of its 12-hour orbit by between 73 seconds and 10 minutes. Thus, DART will practice saving the world from an asteroid collision, like the one that ended the dinosaurs.
Stories of big rocks threatening to hit the Earth have been a staple of science fiction for decades. Indeed, back in 1998, two movies, “Armageddon,” and “Deep Impact,” depicted heroic astronauts saving the world from extinction-level objects. The two movies involved the use of nuclear weapons to destroy the oncoming objects. DART’s mission will be a little less spectacular, testing a technique that will cause an object to miss the Earth entirely.
Until recently, deflecting asteroids instead of using nuclear devices to explode them was the preferred method of sparing the human race from the fate of the dinosaurs. Most scientists who had studied the problem had concluded that blowing up an oncoming asteroid or comet would simply change one huge object into a lot of little ones that would rain down over a wide area of the Earth.
However, according to a recent paper in Acta Astronautica, nuclear weapons may actually be a preferred solution to a kinetic impact vehicle such as DART. Instead of shattering the asteroid, the energy created by a nuclear blast would be used to irradiate a portion of the asteroid’s surface. The asteroid would eject a stream of material that would act as a rocket, diverting the asteroid away from a collision course with the Earth.
Of course, for any method of diverting an asteroid to work, scientists must track Earth-approaching asteroids that could cause an extinction-level event. As BGR reports, NASA tracks Earth-approaching asteroids all the time, including a 1,000-foot-wide object called 4660 Nereus, which is due to pass 3.9 million kilometers from the Earth on Dec.11.
The prerequisite for stopping an asteroid or comet headed to Earth is to detect it, the farther away the better, which suggests that NASA needs to expand its asteroid search operation. If an asteroid or comet is found to be on a collision course with the Earth at a far enough distance, then possibly a kinetic vehicle like DART could be used to bump it into a different path. If the asteroid is detected when it is close and/or if it is of sufficient size and mass that a DART-like vehicle would not be sufficient, then the nuclear option should be made available.
Which organization should be tasked with asteroid defense? Fortunately, the United States has a new military branch that is uniquely suited for such a task: the Space Force.
The Space Force is tasked with defending American and allied space assets from terrestrial enemies, such as China and Russia. No reason exists that it cannot also defend against threats that come from outer space.
The Space Force should be tasked with a mission to test the scenario presented in the Acta Astronautica piece. Such a mission would be tricky diplomatically. The Nuclear Test Ban Treaty prohibits testing nuclear weapons in space. For a test of an asteroid-diverting nuclear device to pass muster, some agreement would have to be acquired from the signatories of the test ban treaty. Perhaps, the nuclear device would not be defined as a weapon for the purposes of the treaty, but as a “deflection device.” The test would be in the best interests of every nation on the planet, so logically there should be little or no objection.
Physicists including Michio Kaku and Neil deGrasse Tyson have remarked: Killer asteroids are nature’s way of saying “how’s that space program coming along?”
If, in some future time, an asteroid is detected on a collision course with Earth and humans have developed the capacity to stop it, every last cent spent on space, NASA, military and commercial space exploration, will be seen as having been worth it, even without all the other benefits. We will have saved the human race, all that we were, all that we are, and all that we might someday become.
Mark R. Whittington is the author of space exploration studies “Why is It So Hard to Go Back to the Moon?” as well as “The Moon, Mars and Beyond,” and “Why is America Going Back to the Moon?” He blogs at Curmudgeons Corner.