Chinese Spy Balloons: Some Thoughts

The balloon was shot down. Some reports suggest it wasn’t the only one — at least one other was flying other US in similar trajectory to the first one, and yet another one is flying other South America heading north.

Point #1. Are balloons worse than satellites?

How much useful those balloons can be, assuming they are indeed spy assets and not a “science balloon taken off course by winds” as official Chinese version goes. The Western mainstream media tries to play down their capabilities and even make fun of inferior Chinese satellite technologies. They say Chinese satellites lack the needed resolution on their cameras. That is actually quite possible and even probable. But let’s consider something. Best Western spy satellites have reported (unclassified) resolution of about 30cm. (the last time I’ve heard). They operate on low orbits, of 200-300km more or less. The Chinese balloon was reportedly operated at altitudes of 30-40km before it started losing its altitude to ~20km and got shot down. So, ~300km vs ~30km. Buy getting 10 times closer to the target, you get 10 times higher resolution (I’m sure technically it’s not true, but you get the point). If Chinese used less advanced cameras with, let’s say, 1m resolution, they would still get better images from their balloons than the West is getting from theirs best satellites. Or, alternatively, a much less sophisticated cameras can be used to get an image resolution equal to that of the best Western spy satellites.

And the optical reconnaissance isn’t the only payload those balloons can be carrying. Signal intelligence is also very important. And, theoretically speaking, those balloons might be used to deliver weapon of mass destruction. While such possibility is extremely remote, the US military and intelligence services must also take this into consideration.

Point #2. It was shoot down as soon as the president made the decision.

This is most probably not true. There is no point to shoot down a spy balloon after it had passed the continental USA. So, the reason to shoot it down was political in nature. It the balloon was to be shot down before entering the continental USA, then the national security would have been the apparent reason.

I suspect USAF had no means to shoot it down before, while it was floating at higher altitudes. It US had been able to do so, it would certainly do it. The reported intercept happened at ~18-19km, which required the use of the most powerful (kinetically speaking) US intercept plane, the F-22. The one which was practically sacrificed for the sake of much less capable but much more profitable F-35 project. It used the imaging infra-red guided short/medium range AIM-9X missile.

USAF operates much more potent active radar-guided missiles, namely the AIM-120D, which has better kinematic performance, allowing it to reach higher altitudes and longer ranges. Yet it wasn’t used, which must mean the balloon was an unsuitable target for this missile’s guidance system. AIM-120 is intended to intercept flying targets such as fighter jets. If the target is not moving relative to its background, in this case the clouds, then the radar-based guidance system will have a hard time detecting and locking on it. For example, the method to guide on hovering helicopters is to detect the doppler shifts in returned radio waves resulting from helicopter’s rotating propellers. In addition, it is possible the balloon used low radio waves reflective materials such as carbon fiber composites, which would decrease its radar signature. So, while AIM-120 AMRAAM should have been the weapon of choice for such high-altitude intercepts, the AIM-9X was used instead.

So why AIM-9X could have seen the unpowered air-balloon better than radar-guided AIM-120. The probable answer is that the intercept happened during the day, meaning the balloon itself and its payload there reflecting sun’s infra-red radiation, thus making it visible to the AIM-9X homing head.

It is interesting to notice that some countries had developed a medium-range IR-guided missiles. Soviets were probably the first ones that put it into wide service. Europe also developed or developing medium range missiles with IR guidance. But US stuck to IR for short range and radar for medium range principle (though some IR-guided AIM-120 prototypes were in development in the past). The probable reason for this is the US investment in stealth technologies. IR-guided missiles are much less sensitive to signature reduction measures. As such, it US would to put a medium-range IR-guided missile in service what negates US stealth jets advantages, it would shoot itself in the leg, so to speak, by proving the stealth jets are far from invulnerable, and not worth their high cost.

In the past US operated a weapon platform that would be perfect for taking down high-altitude spy balloons — the airborne laser (ABL) YAL-1 technology demonstrator. While useless for its original goal of intercepting ballistic missiles on their initial flight phase, it would be a child’s play to burn a thin material of a balloon. Yet this prototype was taken out of test service.

Another question is why it suddenly become possible to shoot down the spy balloon. It USAF managed to do it now, doesn’t it mean it could have done it anytime? The answer is “probably not”. It was reported, what initially the balloon operated at higher altitudes, closer to 30 or even 40 kilometers above the sea level. Yet it was intercepted then it hovered at below 20km. Obviously, the lower it is, the easier it’s to shoot down. If so, why did it get lower? Probably because the helium which is used to fill the balloon making it lighter than air, is also the smallest atom in the periodic table. As such, is can penetrate materials (e.g. the balloon fabric) much easier than any other substance. So, the balloon was probably leaking small amounts of helium all along, gradually and constantly losing its altitude.

If so, isn’t the fact that the balloon was shot down immediately after crossing from continental USA into the ocean proves the USAF could have done it earlier, but didn’t for safety reasons? Yes, probably Pentagon could have shot down the balloon earlier. But then the firstly supplied reason for not shooting it down would be compromised as a valid excuse. And any other balloon entering the US air space would have been expected to be shot down as early as possible, before it could gather the information. So, the only way out was to shoot it down after it left the continental USA airspace (and completed its mission).



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