China Successfully Tested The “Rod of God”

China successfully tested the “Rod of God”: a 9-meter-long crater was smashed, and the power was only equivalent to that of an ordinary bomb

The power of the “Rod of God” (a tungsten rod that hits the ground at high speed from space) has been rumored on the Internet for a long time. Many people believe that its power is comparable to that of nuclear weapons based on the film and their own imagination; a tungsten rod with a diameter of 30 cm, a length of 6 meters, and a weight of several tons, hitting the ground at a super-high speed of dozens of times the speed of sound, can penetrate reinforced targets hundreds of meters underground, and can even destroy a city. Based on this, these people believe that whoever masters the “Rod of God” first, China or the United States, will have a space killer with huge deterrent power against each other.

Some people also question this, believing that even based on the knowledge of middle school physics, it can be understood that energy is conserved. Spending some fuel to send the tungsten rod into space, and then letting the tungsten rod fall, its power, minus the loss, will be significantly less than the energy of the fuel itself. In other words, the power of the tungsten rod is equivalent to the power of the explosion of these fuels. An obvious example is that the maximum speed of an intercontinental missile can reach more than Mach 20, but after it lands, its killing power depends on a nuclear explosion; if it is just a piece of iron, it will only make a big hole.

The two sides have been arguing about this issue. So, what is the real power of the “Rod of God”? The so-called practice is the only criterion for testing truth. If we can actually test it, everyone will understand. As early as 2016, Hong Kong media said that China was developing the “Rod of God” space weapon-few people took it seriously at the time. Who knows, a paper published by a Chinese scientific research institution in 2017 revealed the truth for everyone.

The paper was jointly published by the Chinese Academy of Sciences, the Army Engineering University, and the Nanjing University of Science and Technology. The paper said that China has conducted a “super-high-speed kinetic projectile ground strike test” in a Gobi Desert in the west. The kinetic projectile is a tungsten rod with a diameter of 0.11 meters, a length of 0.84 meters, and a weight of 140 kilograms.

At this point, some people may be a little confused. In some articles, the description of the Rod of God is: 30 cm in diameter, 6 meters long, and 100 kg in weight. With such a light weight, dozens of them can be launched at a time, which is cheap and powerful. But in fact, there is a big mistake here, that is, according to density calculation, since the density of tungsten is close to 20 times that of water, the actual weight of a tungsten rod with a diameter of 30 cm and a length of 6 meters will be as high as 5-10 tons.

In terms of cost, the current cost of civilian space launch is about $10,000 per kilogram. To launch a 5-10 ton tungsten rod, even a civilian platform will cost tens of millions to 100 million US dollars. This cost is not much different from an intercontinental missile.

Therefore, what China actually tested here was only a small tungsten rod with a relatively small volume and a weight of only 140 kg. The paper said that the actual strike results showed that the tungsten rod hit the ground at an ultra-high speed of 4,650 meters per second, smashing a “big pit” with a depth of 3 meters and a diameter of 9.1 meters:

This result is very surprising. Although the tungsten rod is smaller than “rumored”, its power is too small, right? Such a big pit is just like the power of an ordinary bomb.

About that
From the speed point of view, 4650 meters/second is basically 13-14 Mach, which seems to be much smaller than the legendary 24-30 Mach. In fact, the reason is not complicated. Let’s take the intercontinental missile as an example. Although its maximum speed in space can reach about 24 Mach, after re-entering the atmosphere, its speed is constantly decreasing due to air resistance; the actual landing speed is not as high as 24 Mach.

The principle of tungsten rod is the same. Even if it starts in space, due to free fall or partial power, it accelerates to 24 Mach, but after entering the atmosphere, due to resistance, the speed will continue to decrease; the final landing speed is only 13-14 Mach, which is normal.

The speed is only 13-14 Mach, and the mass is only more than 100 kilograms. If you think about it, you will know that its power is not great.

In the paper, several interesting points are mentioned. For example, for general bombs, when the landing speed is between 1-1.5 Mach, it is not that the greater the landing speed, the greater the penetration depth; instead, after 1.4 Mach, the penetration depth will be significantly reduced.

Part of the reason is that below 1.5 Mach, the impedance properties of solid ground (granite) facing high-speed warheads are conventional solids; while in the 1.5-3 Mach range, the impedance properties of solid ground become semi-fluid; and above 3 Mach, it is directly fluid properties. This may partially explain the problem that many earth-penetrating bombs have a low landing speed but a large penetration depth.

Of course, above 1.5 Mach, the role of speed is still relatively large.

However, another problem is that the greater the landing speed, the smaller the slope of the pit. When the speed is not high, the shape of the pit is like this in everyone’s impression:

When the speed is high, it is like a pool of mud hitting the ground, bia, a slanted pit. Just like the “Rod of God”:

From the paper, we know that the “Rod of God” we tested weighs only 140 kilograms. What if it is the legendary “Rod of God” that is 6 meters long and weighs several tons, how powerful is it? This is not difficult to guess. Just imagine that the warhead of an intercontinental missile hits the ground and does not explode. Bia, just a bigger crater.

With such an expensive launch price and such a small strike power, the myth of the “Rod of God” created by the United States seems to be completely shattered.