PLANETARY SECURITYLast-Minute Defense Against an Asteroid: Obliterating It Before Impact

By Evan Gough

Published 7 March 2022

Scientists say that pulverizing a threatening incoming asteroid into tiny pieces is our best bet to protect ourselves from an asteroid on short notice.

Gazing at the night sky can evoke a sense of wonder regarding humanity’s place in the Universe. But that’s not all it can evoke. If you’re knowledgeable about asteroid strikes like the one that wiped out the dinosaurs, then even a fleeting meteorite can nudge aside your enjoyable sense of wonder. What if?

Luckily, planetary defense is at the top of mind for some scientists and engineers. One of those scientists is Professor Philip Lubin from the University of California Santa Barbara. Lubin is developing his idea called PI-Terminal Defense for Humanity. The PI stands for Pulverize It, and Lubin thinks pulverizing an incoming impactor into tiny pieces is our best bet to protect ourselves from an asteroid on short notice.

Lubin presented his PI Planetary Defense idea at the 2021 Planetary Defense Conference. His idea is now a Phase One awardee in the NASA Innovative Advanced Concepts (NIAC) program. NIAC aims to promote and support visionary ideas that can transform future NASA missions. NASA operates the Planetary Defense Coordination Office (PDCO), and Lubin’s PI Planetary Defense idea fits that office’s mandate.

The threat of an asteroid strike is genuine. A massive asteroid like the one that wiped out the dinosaurs would kill our civilization. We’ve faced more minor threats, like the Tunguska Event and the Chelyabinsk meteor, but can we count on luck to avoid devastating impacts? That wouldn’t be wise.

“So far, humanity has been spared large-scale catastrophe as was visited upon our previous tenants, but counting upon being “lucky” is a poor strategy in the longer term,” Philip Lubin said in 2021.

NASA is busy finding and cataloguing asteroids that pose a threat to Earth. But that’s only an initial step. We must develop ways to protect Earth from a catastrophic impact.

Much of the thinking around asteroid impact mitigation is focused on long lead times. If we know months or years ahead of time when an asteroid will impact Earth, we can send out a kinetic impactor to redirect the asteroid. With enough lead time, even a small kinetic impactor can redirect a large asteroid away from us.

But what if time is short? What if we find out too late? What if we’ve launched a kinetic impactor, but it missed or failed somehow? That’s where Lubin’s PI idea could come into play.