{"id":4852,"date":"2021-07-21T10:03:49","date_gmt":"2021-07-21T17:03:49","guid":{"rendered":"http:\/\/128.111.23.62\/wordpress\/?page_id=4852"},"modified":"2023-09-14T04:20:10","modified_gmt":"2023-09-14T11:20:10","slug":"pi-terminal-planetary-defense","status":"publish","type":"page","link":"http:\/\/128.111.23.62\/wordpress\/projects\/pi-terminal-planetary-defense","title":{"rendered":"PI – Multimodal Planetary Defense"},"content":{"rendered":"

\"\"<\/h3>\n

<\/p>\n

 <\/p>\n

\"NASA<\/p>\n

 <\/p>\n

 <\/p>\n

<\/h3>\n

Links to papers:<\/strong><\/h3>\n

Detailed technical paper:<\/em><\/strong><\/h3>\n

PI-Terminal-Defense<\/a><\/h3>\n

arXiv archive link:<\/strong><\/h3>\n

http:\/\/arxiv.org\/abs\/2110.07559<\/a><\/h3>\n

ASR – Advances in Space Research – 10-22<\/strong><\/h3>\n

https:\/\/www.sciencedirect.com\/science\/article\/pii\/S0273117722009395<\/a><\/h3>\n

Scientific American Article:<\/em><\/strong><\/h3>\n

https:\/\/www.scientificamerican.com\/article\/planetary-defense-is-good-but-is-planetary-offense-better<\/a><\/h3>\n

UCSB Press Release 10-11-21:<\/strong><\/em><\/h3>\n

https:\/\/www.news.ucsb.edu\/2021\/020432\/planetary-defense-pi-sky<\/a><\/h3>\n

Summary Briefing Charts:<\/strong><\/em><\/h3>\n

PI – Lubin-l<\/a><\/h3>\n

Don’t Forget to Look Up 1-25-22<\/strong><\/em><\/h3>\n

A Physicist’s View of Hollywood and Existential Threats<\/h4>\n

https:\/\/arxiv.org\/abs\/2201.10663<\/a><\/h3>\n

CBS Coverage on the “Don’t Forget to Look Up” paper (many others on the net with less fidelity)<\/strong><\/h3>\n

https:\/\/www.cbsnews.com\/news\/asteroid-dont-look-up-nuclear-explosives\/<\/a><\/h3>\n

UCSB Deepspace YouTube Channel \u2013 PI Movies and Additional Materials<\/strong><\/h3>\n

www.youtube.com\/@UCSBDeepspace<\/a><\/h3>\n

UN Meeting on Planetary Defense – PDC 2023 – Vienna -April 2023<\/strong><\/h3>\n

https:\/\/www.unoosa.org\/oosa\/en\/ourwork\/topics\/neos\/2023\/IAAPDC\/index.html<\/a><\/h3>\n

PI talk at the end of session 8 April 6, 2023<\/strong><\/h3>\n

https:\/\/media.un.org\/en\/asset\/k11\/k112i49pj8<\/a><\/h3>\n

List of Acoustic and Optical Ground Effect Simulations on Youtube<\/strong><\/h3>\n

List-of-Acoustic-and-Optical-Simulations<\/a><\/h3>\n

List of Hypervelocity Intercept Simulations on Youtube<\/strong><\/h3>\n

List of Hypervelocity Intercept Simulations<\/a><\/h3>\n

\u03c0<\/strong><\/em><\/h1>\n

Multimodal Planetary Defense<\/strong><\/em><\/h1>\n

 <\/p>\n

<\/h3>\n

PI is a practical and effective method of planetary defense that allows for extremely short mitigation time scales if needed as well as general use for longer warning times cases.<\/strong> 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\u2019s atmosphere to dissipate the fragment cloud where the atmosphere acts as a “bullet proof vest” or “body armor” for short warning time threats while the fragments miss the Earth for longer warning time threats.<\/strong> The effects of doing so are remarkable in their effectiveness. In the terminal defense mode the key is to de-correlate the resulting acoustic blast waves on the ground and to take into account the optical signature due to fragment “burnup”.\u00a0 Understanding both effects and and spreading the fragment cloud both spatially and temporally allows for virtually any threat to be mitigated. PI stands for “Pulverize It”<\/strong>.<\/h3>\n

The system allows a terminal defense solution to planetary defense using existing technologies.\u00a0 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.<\/h3>\n

\u00a0 \u00a0 \u00a0 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 diameter, ~ 4 Gt yield) would 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 a 100 second prior to impact intercept with a 10m\/s disruption and 1000 second prior to impact with a 1m\/s disruption. Zero-time intercept of 20m class objects are possible due to atmospheric dispersion effects. The theoretical details and the analytic and numerical simulations showing the program works is discussed in our technical papers.\u00a0<\/strong><\/h3>\n

<\/h3>\n

Summary of PI Mitigation Modes<\/strong><\/h1>\n

 <\/p>\n

1) Short time warning \u2013 minutes to days intercept \u2013 terminal defense (15m to 100m diam threats)<\/em><\/strong><\/h3>\n