As if last year’s exciting double-asteroid redirection test (firing satellite bullets at an asteroid) wasn’t enough, now researchers are conducting detailed simulations of the nuclear deflection scenario envisioned in the 1998 space disaster movie “Armageddon.”
At Lawrence Livermore National Laboratory, a team led by Mary Burkey (above) published a paper that spurred what is actually a pretty active field of research. As they point out, using satellites as missiles is not always feasible, and in fact detonating a nuclear explosive device as close as possible to the incoming object may be our best move.
The problem is that nuclear deflection needs to be done in a very precise way, otherwise it could cause (as it did in “Armageddon”) a chunk of an asteroid to hit the Earth. This could lead to a scenario of massive destruction of the sort envisioned in the 1998 space disaster film Deep Impact.
As Burkey et al. explain in their paper published in the Journal of Planetary Science:
Even setting aside the asteroid’s complex structure and inhomogeneous material properties and approximating it as a uniform sphere, the sheer breadth of physics required creates difficulties.
Fully simulating energy deposition requires particle transport in a complete radiation hydrodynamics code with detailed material models, and is computationally expensive because the time steps must be small to simulate radiation interactions with asteroids. Even running a simulation on 200,300 CPUs can take weeks.
No single code can cover all 10 orders of magnitude while correctly accounting for all the different packages of entities, so it is advisable to divide the problem into stages and hand off the process to a code that covers the relevant physics of the next stage.
Since most of the energy from a nuclear explosion is X-rays (I learned today), modeling how they propagate and initially interact with the asteroid surface is a critical step. This paper provides a more complete and inclusive simulation of such an effort, “utilizing a full radiative hydraulic simulation equipped with changing opacity, making it the first comprehensive effort to explore high-flux regimes.” , in which destructive mitigation tasks will be performed.”
In other words, it’s one of the first to actually look at what would happen if we nuke an asteroid. Since that’s what you’re here for, it looks like this:
Image Source: Burkey et al.
This all happens in one second, as you can see from the time notation (1e+06 microseconds are one million microseconds that make up a full second).
The paper doesn’t go beyond its initial findings, essentially that this simulation method is accurate enough that we can rely on it for larger studies of asteroid nukes:
The completion of this energy deposition model opens up a range of potential studies that can be done using large-scale fluid dynamics codes… properties such as material/density distribution, rotation, irregular shapes, shadows cast by boulders, gravity edge pulls, etc., even though Both larger-scale components also require more detailed study of their impact on mission outcomes. In particular, understanding whether attempted deflection missions would break up asteroids has been a long-standing question in the planetary defense community.
Each detailed high-fidelity simulation and each extensive sensitivity scan brings the field closer to understanding the effectiveness of nuclear mitigation.
The team also called for running faster simulations (which take a long time) that can be executed against a given threat to minimize response times. Since machine learning has proven useful in situations like this, perhaps artificial intelligence can be used to save humanity instead of destroying it, this time.
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Image Source : techcrunch.com