As if last year’s amazing Dual Asteroid Redirection Test that fired a satellite bullet into an asteroid wasn’t enough, now researchers are doing a detailed simulation of the nuclear deflection scenario envisioned in the 1998 space disaster. movie “Armageddon.”
At Lawrence Livermore National Lab, a team led by Mary Burkey (above) presented a paper that moved the ball forward in what is truly an active area of research. As they point out, using a satellite as a missile isn’t always practical, and actually detonating a nuclear explosive device as close as possible to the incoming object is our best bet.
The problem is that a nuclear deflection must be done in a very precise way or else it could lead (like “Armageddon”) to fragments of the asteroid hitting the Earth. This could result in the massive destruction scenario envisioned in the 1998 space disaster film “Deep Impact.”
As Burkey et al explained in their paper published in the Planetary Science Journal:
Even if the complex structure of an asteroid and non-uniform material properties are isolated and the object is approximated as a uniform surface, the sheer breadth of the required physics presents difficulties.
A full simulation of energy deposition requires particle transport within a full radiation-hydrodynamics code equipped with detailed material models and is computationally expensive, as the time steps must be small. to model the interaction of asteroid radiation. It can take several weeks to run a simulation even with 200300 CPUs.
No single code can cover all 10 orders of magnitude while properly accounting for all the different physics packages, so dividing the problem into stages and delegating progress to code containing the relevant physics of the next stage is desirable.
And since most of the energy produced in a nuclear explosion is X-rays (which I now know), simulating how it propagates and initially interacts with the asteroid’s surface is a critical step. . This paper provides a more complete and inclusive simulation of such an effort, “using a full rad-hydro simulation equipped with variable opacities, which also makes it the first comprehensive effort to explore the high-fluence regime in which a disruption-style mitigation mission will operate.”
In other words, it’s one of the first to look at exactly what happens, microsecond by microsecond, when we nuke an asteroid. And since that’s what you came here for, it goes like this:
That all happens in one second, as you can see from the time notation (1e+06 microseconds is one millionth of it, which makes up one full second).
The paper does not go beyond its tentative findings, which are essentially that this simulation method is accurate enough that we can rely on it for a larger-scale study of asteroid-nuking:
The completion of this energy deposition model opens up many potential studies that can be completed using large hydrodynamic codes… Properties such as material/density distribution, rotation, irregular shapes , shadows cast by rocks, the marginal pull of gravity, and even composition on a larger scale all require more detailed studies of their effect on the outcome of a mission. In particular, understanding whether an attempted deflection mission would destroy an asteroid has been a long-standing question in the planetary defense community.
Each detailed, high-fidelity simulation and each broad sensitivity sweep brings the field closer to understanding how effective nuclear mitigation can be.
The team also calls for faster running simulations (it’s an age) that can be specific to a given threat, reducing response time. As machine learning has proven useful in contexts like that, perhaps AI can be used to save humanity instead of destroying it, once and for all.
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