On 30 June, Asteroid Day, I was privileged to have been asked to address the Los Angeles – Las Vegas American Institute of Aeronautics and Astronautics Conference on Planetary Defense held in Redondo Beach.
Last week, my post provided an introduction to this important event based on all the other presentations at this conference. This week, as promised, I will discuss my presentation and some of the questions asked and answers given.
You can find my PowerPoint charts here: Planetary Defense 2018.
The title of my presentation was “Predictably Effective Planetary Defense Systems”.
In any deck of charts, no matter how large, there should be one that summarizes the entire deck. It should contain the point you intend to make. Stated in another way, you should be able to brief the entire presentation from that chart. The following reproduces that chart from my presentation:
A Planetary Defense System must be continually demonstrated (by monitor, test, analysis) to be…
Effective: Eliminates or mitigates threat (design)
Reliable: All required functions work (measured)
Available: Ready to be used when needed (even after use)
Survivable: Can’t be harmed prior to use (people or nature)
Economical: Can be kept viable with resources available
Anti-Fragile: Stress improves system (beyond long-lived)
Safe & Sure: Doesn’t harm people, things, environment & works only when commanded
The key part of this excerpt is the focus on “continually demonstrated”. It is understandable that design engineers will focus on what the system needs to be in terms of initial effectiveness. But it must not be forgotten that once deployed, it will be essential to keep it working in tip-top shape, and be improved over the years. Funding to make this happen will most likely, in this case, come from US taxpayers. They must have confidence today, tomorrow, and the next day that the system works or they will stop funding it.
I told the audience that my experience keeping highly complex ICBMs viable since the 1950’s yields lessons in how to design a planetary defense system. So there were also charts explaining what ICBMs are, why they are highly complex, and how they were kept working for decades.
The conclusions chart says that a Planetary Defense System that can be sustained indefinitely would include hardware that is, as far as possible, predictable and state-of-the-practice. It would consist of many copies, closely tracked and tested. And the system would lend itself to continuous upgrades.
Broadly speaking, a Planetary Defense System would need (among other things) world-wide and orbital sensors to find and track asteroids, a command and control capability to trigger the defense, and then some kind of active weapon design to eliminate or reduce the destructiveness of the asteroid. It is likely that, at least in the near term, many copies of rockets would be part of the third major subsystem. In many instances, nuclear bombs might be the best way to mitigate the threat. Because of this and because I was speaking about ICBMs, a lot of discussion centered around the idea of using nuclear bombs.
I found myself advising caution about using this approach. From a purely technical point of view, it probably is the best one in the short term for a certain class of asteroids. If you would like to read up on this issue before continuing, you are in luck. AIAA’s magazine, Aerospace America, just recently addressed this.
For an anti-nuke argument see: https://aerospaceamerica.aiaa.org/departments/nuclear-nonsolution/
For a pro-nuke argument see: https://aerospaceamerica.aiaa.org/departments/earths-best-defense/
The main focus of my concern was the generational work that my fellow ICBM engineers have accomplished over the years with other US Government experts in reducing the numbers of nuclear weapons via treaties. Nuclear explosions that take place here on the Earth do a tremendous amount of ecological damage. The best path to eliminating these explosions on the surface of our planet would be to eliminate these weapons completely. Do not leave any capability in place on this planet to create them.
I also tried to make the point that continuing the momentum of eliminating these bombs is hard enough without attempting to carve out exceptions for planetary defense. I was thinking about the way Russia, for instance, will protest any missile defense system as de-stabilizing to deterrence. Serious work on the planetary defense system will enter that same diplomatic space. Nukes will only further complicate those discussions.
There are, of course, other considerations. This is probably the most important: These bombs can be made “safe” in that a rocket that fails to operate correctly and crashes back to Earth will not result in a nuclear detonation. However, a pile of burning rubble that contains a nuclear device is never a good thing.
What might be done without nuclear bombs? Kinetic impact. Directed energy. Placing devices on the asteroid to nudge it using various schemes. These and other options are already being debated. Key to this debate is effectively categorizing asteroids into groups. For instance, broadly speaking, a lot of time and distance allows for lower energy “nudging” solutions. But lack of warning time severely limits options. Many other categories are being discussed as well such as what the asteroid is made up of or how many pieces and what shapes the asteroid is. (Yes, asteroids can have “moons”.)
In the case of sizes and trajectories that result in short warning times, defenses are likely to be Earth-bound and regional (perhaps continental US plus some parts of Canada and Mexico). They would likely resemble current missile defense systems such as the Ground-Based Mid-Course Defense system currently in place at Fort Greeley, Alaska and Vandenberg Air Force Base, California. This raises the questions (stated very well by one of the participants) just how quickly can we create this kind of system with a sufficient effectiveness? And this gets us back to the potential protestations from other countries like Russia. I reminded the audience that a similar concern was raised in the Reagan “Star Wars” Defense years. The answer at that time was to assist Russian in creating their own regional defense system. And this takes us full circle from my initial assertion that US taxpayers would pay for all of this. The reality will be much more complicated than that.
I think this post is long enough for this week. I would ask those who were at the conference to contribute in the comments section. Are there points that you felt were important that I have left out?