Pentagon Wants Pournelle's Rods from God

Back in the 1950s, Jerry Pournelle (who later became a best-selling science fiction writer), proposed a weapons system called Thor, also known as "Rods from God", basically a tungsten rod dropped from orbit that would hit its target with the energy of a small nuclear bomb. 

That proposal hasn't come to fruition yet, but both the United States and Russia (and likely China too) are working on hypersonic kinetic energy weapons that would have the energy of a large conventional bomb. An article in Task and Purpose looks at the current state of the technology.

The idea of kinetic weaponry — raining down inert projectiles on an enemy with deadly velocity — is far from a novel concept. The trebuchet was the backbone of successful sieges for hundreds of years, from ancient China to Hernan Cortes’ subjugation of the Aztecs; during and after World War II, airmen have occasionally deployed clusters of inert “Lazy Dog” bombs — metal cylinders traveling at terminal velocity — on the battlefields of Korea and Vietnam.

And gravity hasn’t always been necessary. For decades, militaries have used ultra-dense “kinetic energy penetrators,” also known as KEPs, specially designed shells often wrapped in an outer shell (a “sabot”) and fired at high velocity rather than dropped from the sky, to defeat defense armor. That’s the fundamental logic underpinning the U.S. Navy’s highly touted electromagnetic railgun, which can blast a 25-pound “hypervelocity projectile” with 32-megajoule muzzle energy through seven steel plates and obliterate whatever that armor is supposed to protect.

Whether dropped from the sky or fired from a cannon, the principle behind these weapons is the same: hitting the enemy with something very hard and very dense, moving very fast. And the kinetic energy projectile may become a staple of modern warfare sooner than you might think.