Speaker
Description
Keywords: Asteroid Deflection, Asteroid Disruption, Nuclear Mitigation Strategy, Asteroid Composition, Near-Earth Object
Session: Deflection/Disruption Modeling and Testing
Space is perpetually monitored by scientists for near-Earth objects (NEOs) that could potentially collide with Earth. If a problematic NEO is detected early enough, then multiple mitigation options can be devised. One mitigation option is to detonate a nuclear explosive device (NED) a short distance from the NEO so the surface material vaporizes and is blown off by the deposited X-rays, which imparts a shift in momentum, redirecting the NEO away from Earth. This process involves some of the X-rays being deposited into the NEO while the rest are reradiated away at the surface. The interplay between these two processes is critical for calculating the effectiveness of this mitigation option. The success of asteroid disruption and deflection is correlated with blowoff momentum, which can be used to calculate the NEO’s deflection velocity.
The momentum of blown-off surface material is highly dependent on the composition of the asteroid. Previous work by Burkey et al. (2023) simulated the first few microseconds of NED detonations near asteroids in Kull (a radiation-transport hydrodynamics code created for inertial confinement fusion) using simple, asteroid-like materials: SiO2, Forsterite (Mg2SiO4), Iron, or Ice. Because NEDs cannot be tested in space, this work must be done through simulations. Incorporating realistic and complex material compositions such as CI Chondrite-type asteroids increases the accuracy of these simulations.
Preliminary calculations, shown in Fig. 1, indicate that changing the simulated opacity to better reflect complex, asteroid-like compositions leads to significant differences in the magnitude of blowoff momentum.
Fig. 1: Percent difference in blowoff momentum as a function of fluence when the opacity of the asteroid is changed from the opacity of the original material to the opacity of CI Chondrite for materials: SiO2 (purple), Forsterite (green), Ice (blue).
We present a study demonstrating how changing the varied material composition of realistic asteroids affects the blowoff momentum using similar simulations to those in Burkey et al.
Prepared by LLNL under Contract DE-AC52-07NA27344.
LLNL-ABS- 2001302