A new study by Lawrence Livermore National Laboratory (LLNL) and the Air Force Institute of Technology (AFIT) is investigating how the neutron energy generated by the explosion of a nuclear device can deflate an asteroid.
Scientists compared the two different neutron energy source (fission neutron nuclear fusion neutron) asteroid deflection caused by the parallel comparison to these two kinds of neutron energy source, the purpose is to know the nuclear blast which neutron energy released is more advantageous to the asteroid deflection, and revealed the reasons, lay a foundation for optimizing the asteroid deflection effect.
The new study, published in a recent issue of the Journal of American Astronautics, was led by Lansing Holland as part of the Planetary Defense and Arms Export Project with LLNL Lab while he was a graduate student in nuclear engineering at AFIT. "The team focused on neutron radiation from nuclear explosions. Because neutrons are much more penetrating than X-rays, this means that the heat generated by neutrons could have heated much more material on the asteroid's surface, and therefore could have been more effective at deflating the asteroid than the heat generated by X-rays."
Neutrons with different energies can interact with the same material through different interaction mechanisms, and by changing the distribution and intensity of the deposited energy, the orbit of the asteroid will also have a deflection effect.
Study shows that the energy deposition profile analysis reflects the asteroid surface under the diversification of energy deposition distribution of space position, which in May have a lot of differences between two kinds of neutron energy, the energy of the deposition distribution on the asteroid is not at the same time, means that the melting/evaporation from the number of pieces and speed change, this will determine the asteroid the speed of change in the end.
The United States has begun a study of how to destroy potentially dangerous asteroids with a nuclear device
An asteroid that destroys a potential threat
There are many potentially dangerous asteroids in Earth's orbit that could break into Earth's orbit or even enter the Earth's atmosphere and cause a catastrophic collision. Holland points out that there are two basic scenarios for destroying these potentially dangerous asteroids: Shattering, or deflecting, is a method of delivering high energy to an asteroid. It will shatter into lots of fast-moving debris. Previous studies have shown that more than 99.5% of the debris from an asteroid will miss Earth when it is blown up. So if the lead time for an asteroid to hit Earth is short or the asteroid is relatively small, we can consider blowing it up.
"Deflecting an asteroid orbit is a milder method that involves giving the asteroid less energy, keeping the asteroid intact, and pushing it into the deflected orbit at a slightly altered speed," he said. Over time, many years before the asteroid hit the earth, even minor changes will increase the speed of it from the earth, if we have enough time to predict an asteroid collision earth several conference, can adopt deflection asteroid orbital method, it is usually considered a safer, more "elegant" option. That's why we're currently focusing on how to deflect asteroids."
Linking energy deposition to asteroid reactions
The work will be carried out in two main phases, including: Neutron energy deposition and asteroid deflection response, for the energy deposition phase, the luo, los alamos national laboratory in monte carlo N particles (MCNP) to simulate the radiative transfer code all the different case studies, MCNP simulated a neutron confrontation explosion, radiation toward a 300 meters of the diameter of the composition of silica based spherical asteroids, Asteroids are divided into hundreds of thousands of small units by hundreds of concentric spheres and closed cones. The energy deposits of each small unit are then statistically tracked to produce a profile, or spatial distribution, of the entire asteroid's energy deposits.
For the asteroid deflection phase, the response of the asteroid composition to energy deposition was simulated using the LLNL Laboratory's 2D and 3D random Lagrangian-Euler (ALE3D) hydrodynamics codes. The energy deposition profile generated by MCNP was imported and mapped to the ALE3D asteroid for easy initialization of the simulation. The effects of neutron energy on the deflection of an asteroid can be shown by obtaining the variation of the deflection velocity under different neutron yield and neutron energy configurations.
A small step to deflect an asteroid could determine the fate of Earth
"This latest study is a small step towards using a nuclear device to deflect an asteroid," Holland said. "Our ultimate goal is to determine the optimal neutron energy spectrum, the diffusion of neutron energy output, and store their energy in an optimal way to maximize the impact or deflection of the asteroid. This study reveals how certain neutron energy outputs can affect the deflection properties of asteroids and why this happens as a stepping stone to larger targets."
He also pointed out that the energy deposition data precision and accuracy is very important, if the energy deposition input is not correct, we should not be too much for an asteroid deflection output confidence, we now know that the energy deposition profile for a large asteroid deflection is of great significance, if in the future, human a space mission, is used to reduce the threat of a large meteorite collision earth, Spatial profiling analysis of energy deposition should be considered to correctly simulate the expected asteroid velocity variation.
On the other hand, energy coupling efficiency has always been an important factor for scientists to consider, even for smaller asteroids, Holland says: "We found that the amount of energy deposition is the best predictor of the overall deflection of the asteroid, and has a greater influence on the final velocity change than the spatial distribution. In order to plan asteroid deflection missions, it is necessary to take these energy parameters into account so that correct simulations and predictions can be made."
Most importantly, we need to further study and understanding of all the asteroids migration technology, in order to make the most of the current science and technology power, and in some cases, the use of a nuclear device makes the asteroid deflection more advantage than the nuclear device, in fact, if an asteroid collision warning time is very short, or an asteroid collision events volume is very big, A nuclear explosion may be our only viable option for deflecting and destroying asteroids.