Part 1 of 2 parts
    I write two blogs, one on nuclear issues and the other on the space industry. Sometimes I run across stories that could be posted in either blog because they combine nuclear issues with space such as a nuclear propulsion system for space craft or nuclear batteries for deep space missions. Since I post to my nuclear blog five times a week and only once a week to my space blog, I require a lot more content on the nuclear blog. I decided that today, I would post one of these combined subject posts to the nuclear blog.
     There are many reasons for space missions but there is only one type of mission that has implications for the survival of human civilization. There are many asteroids that regularly cross the orbit of the Earth around the Sun. Asteroid strikes have had a massive impact in the past on the ecosystem of the Earth and they will obviously do so in the future. The big question is whether or not we will be able to deflect a major asteroid that is headed for an impact on the Earth.
     The Lawrence Livermore National Laboratory (LLNL) and the Air Force Institute of Technology (AFIT) have formed a research collaboration to explore how the neutron energy from a nuclear warhead detonation can affect the deflection of an asteroid headed for the Earth.
     The researchers compared the way an asteroid is deflected from two different neutron energy sources. The two neutron sources are a fission detonation and a fusion detonation. Their immediate goal was to understand which of these neutron energy releases from a nuclear explosion would be better for deflecting an asteroid. They are also interested in just exactly why and how these two different nuclear detonations differ. The ultimate goal of the research is to optimize deflection performance.
     The work of the collaboration has been published in the  journal Acta Astronautica. It was led by Lansing Horan IV, as part of a collaboration with LLNL’s Planetary Defense and Weapon Output groups during his nuclear engineering master’s program at AFIT. Co-authors from LLNL include Megan Bruck Syal and Joseph Wasem from LLNL’s Weapons and Complex Integration Principal Directorate, and the co-authors from AFIT include Darren Holland and Maj. James Bevins.
     Horan said that his research team focused on the neutron radiation from a nuclear explosion because neutrons can penetrate material objects better than X-rays. “This means that a neutron yield can potentially heat greater amounts of asteroid surface material, and therefore be more effective for deflecting asteroids than an X-ray yield.”
     Neutrons that have different energies can interact with the same material through different mechanisms of interaction. By changing the distribution and intensity of the energy deposited in the asteroid, the resulting trajectory of the asteroid can be affected.
     This research generated energy deposition profiles which map the spatial locations at and beneath the curved surface of the asteroid where energy is deposited in varying distributions. They show that the deposition can be very different between the two neutron energy sources that were compared in this research. When the deposited energy is distributed differently in the asteroid, this indicates that the melted/vaporized blow-off debris can change in amount and speed, which ultimately determines the asteroid’s resulting velocity change.
Please read Part 2 next