'Rods from God' not that destructive, Chinese study finds

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Chinese scientists may have found that the much-vaunted superweapon known as the "Rods from God" may not have been that effective, the South China Morning Post (SCMP) reports. First dreamed up during the "Cold War" this new research may indicate that kinetic orbital bombardment may not have been a good investment of resources if ever attempted.

While never developed (as far as we know), this weapon would have seen large 19.7-foot (6-meter) tungsten rods launched from orbit to hit targets on the ground at hypersonic speeds. Since tungsten is incredibly dense, its impact on the Earth's surface would release a terrifying amount of energy. Perhaps even as much, if not more, than a nuclear explosion (but without all that messy radioactive fallout).

But this vision of destruction may not be entirely accurate. A recent experiment by researchers at North University in Taiyuan, Shanxi province, aimed to investigate the impact of a weapon hitting a military concrete bunker. The results of the experiment were surprising. The group of scientists, headed by Fu Jianping from the university's intelligent weapon research institute, used mechanical and electrical engineering to increase the speed of tungsten rods to an astounding 1.86 miles per second (3 km per second). That's almost nine times the speed of sound.

They found that when the rod hit a target, it generated a high-pressure shockwave that compressed the target material. This, in turn, created extremely high temperatures and pressures, turning the target area into plasma. When in a plasma state, the material becomes highly conductive to electrical currents produced by the high-pressure shock wave. The researchers explained that these currents could cause a magnetic field to form and interact with the plasma, generating a force that propels the plasma to even greater speeds.

Then the accelerated plasma creates a jet that helps erode the target material and aids penetration. However, the tungsten rod also experiences the same erosion due to the high-temperature and high-pressure conditions caused by the plasma jet's interaction. Fu's team discovered that at Mach 8, an entire arms-length rod could disappear almost instantly upon impact.

“It is very necessary to study the penetration of tungsten rods into concrete at hypersonic speeds,” Fu and his colleagues wrote in the paper. “With the development of launch platform technology, the speed of rod-type projectiles is increasing. However, the destructive effects of tungsten rods against concrete vary between hypersonic and conventional speeds. The destructive mechanism also changes accordingly,” the paper said.

“There is a maximum penetration depth of about 80 times that of the projectile diameter at the speed of 1.2km per second [about 3.5 times the speed of sound],” Fu’s team said. Increasing the speed to hypersonic levels, beyond Mach 5, would not result in the tungsten rod penetrating any further into the concrete. “The penetration depth under ultra-high speed conditions has no advantages over medium and low-speed penetration,” the team said.

Impressive, but not as devastating as many have come to believe. Let's just hope no nation tries them for real in any case.