NASA Funds Research into Destroying Incoming Asteroid on Short Notice
by Douglas Messier
Managing Editor
NASA is funding research into hypervelocity kinetic penetrators that would allow for the destruction of an incoming asteroid on very short notice.
The space agency awarded a NASA Innovative Advanced Concepts (NIAC) Phase I grant worth $175,000 to Philip Lubin of the University of California, Santa Barbara for his “Pi — Terminal Defense for Humanity project.
“The method involves an array of small hypervelocity kinetic penetrators that pulverize and disassemble an asteroid or small comet. This effectively mitigates the threat using the Earth’s atmosphere to dissipate the fragment cloud,” the proposal abstract said.
“The proposed system allows a practical, low-cost terminal defense solution to planetary defense using existing technologies. This approach will work in extended time scale interdiction modes where there is a large warning time, as well as in short interdiction time scenarios with intercepts of hours to days before impact,” the document added.
The project abstract follows.
Pi – Terminal Defense for Humanity
Philip Lubin
University of California, Santa Barbara
NIAC Phase I
Amount: $175,000
Length: 9 months
We present a practical and effective method of planetary defense that allows for extremely short mitigation time scales if required. The method involves an array of small hypervelocity kinetic penetrators that pulverize and disassemble an asteroid or small comet. This effectively mitigates the threat using the Earth’s atmosphere to dissipate the fragment cloud.
The proposed system allows a practical, low-cost terminal defense solution to planetary defense using existing technologies. This approach will work in extended time scale interdiction modes where there is a large warning time, as well as in short interdiction time scenarios with intercepts of hours to days before impact.
In longer time intercept scenarios, the disassembled asteroid fragments largely miss the Earth. In short intercept scenarios, the asteroid fragments of maximum ~10-meter diameter allow the Earth’s atmosphere to act as a “beam dump” where the fragments either burn up in the atmosphere or air burst, with the primary channel of energy going into spatially and temporally de-correlated shock waves.
Compared to other threat reduction scenarios, this approach represents an extremely cost effective, testable, and deployable approach with a logical roadmap of development and testing. Pre-deployment of the system into orbit or a lunar base allows for rapid response on the order of less than a day if needed. The effectiveness of the approach depends on the time to intercept and size of the asteroid, but allows for effective defense against asteroids in the multi-hundred-meter diameter class and could virtually eliminate the threat of mass destruction caused by these threats.
The great advantage of this approach is that it allows for terminal defense in the event of short warning times and target distance mitigation where orbital deflection is not feasible. Even intercepts as close as the Moon with intercept times of a few hours prior to impact are viable. Using the Moon as a planetary defense outpost with both detection as well as mitigation (launch) capability is one option to be considered for the future to protect the Earth.
The Moon is nearly ideal given the lack of atmosphere allowing for long range optical/NIR LIDAR detection, and the low escape speed allows for rapid launch and interception capability. For an Earth launch-based system, we show that a single heavy lift launcher such as a Falcon Heavy, Starship, SLS etc. can mitigate a multi-hundred-meter diameter asteroid at intercept ranges within a lunar distance if needed.
As an example, we show that with only a 1m/s internal disruption, a 5 hours prior to impact intercept of a 50m diameter asteroid (~10Mt yield, similar to Tunguska), a 1 day prior to impact intercept of 100m diameter asteroid (~100Mt yield), or a 10 day prior to impact intercept of Apophis (~370m diam., ~ 4 Gt yield) would largely mitigate these threats. Mitigation of a 1km diameter threat with a 60-day intercept is also viable. We also show that a 20m diameter asteroid (~0.5Mt, similar to Chelyabinsk) can be mitigated with less than a 15-minute prior to impact intercept with a 10m/s disruption.
Even a 2-minute prior to impact intercept of 20m class threats is viable. Pro-active mitigation of these threats is also an option. Having such a capability would allow humanity for the first time to take control over its destiny relative to asteroid and comet impacts.
12 responses to “NASA Funds Research into Destroying Incoming Asteroid on Short Notice”
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What is unspoken is that the same kinetic weapons developed for Planetary Defense could be easily adapted for other uses. Also interesting in that it is using a Starship/Super Heavy as the delivery vehicle although they do give the politically required node to the SLS. I am sure that the USSF is following this with interest.
Concern would e somewhat similar to the problem with nuclear destruction. Turning one massive impact into many serious impacts if everything doesn’t go according to plan.
Yes, and let’s not forget how different impact on the atmosphere of a cloud of impacts versus a single impact. Best strategy still is to locate a NEO far enough out to use a portable mass driver to alter the orbit.
Which doesn’t mean that a relatively quick-to-build system that is good enough isn’t a good thing to have in case a notionally better solution can’t be applied in time or doesn’t work.
That would a worst-case scenario – and still better than one giant impact.
That depends on a lot of details. The same energy being delivered to Earth in either case, it depends on how it is delivered. Distant memory is that increasing a thermonuclear weapon size by an order of magnitude allows it to destroy the same area as three of the original size. Or three of the one megaton units can destroy the same area as one of the ten megaton units. Assuming total energy delivered to the ground is similar, multiple smaller impacts can (can, not will without detailed information) result in much more destruction than the single hit.
Assuming it does pulverize the incoming to powder and small boulders, there would still be just as much energy delivered to the upper atmosphere over much larger area. There are many variables to consider. A gigaton of energy impact in one place or a gigaton of energy scattered across hundreds of miles. Like getting hit with a rifle or a shotgun the details matter a lot.
And where it will be impacting. If its in the Arctic, Antarctic, Outback, Amazon, Sahara or Gobi a single impact might be better. If it is in the ocean, than the multiple impacts might produce less damage (no tsunami). Seems this would be a good research project for the folks at Sandia to do.
I agree that much more information on this topic is needed. It would be good to know exactly what type of response would be best assuming that there will be impact(s). Also agree that locating and classifying potential impacters is the key. Ignorance is not bliss, it is a sign on your back that says “kick me”.
There is at least one, possibly more, conference proceedings with papers covering this topic ad infinitum.
Thanks. Good to know.
You open up more mass into surface area that the atmosphere can turn into air bursts…where the energy falls off by the cube…not the square as it surface waves…IIRC
Unspoken because obvious, one supposes. Most weapons support multiple use cases.
Starship stacks will be the only launch vehicles able to both carry a maximum penetrator payload for really big threats and to be available on short notice for such work fairly soon.
I, too, hope USSF will follow this with interest. USSF is far more likely, based on recent statements, to have a capability to see such threats coming in a few years time than will NASA.