Indian Air ForceIndian Defence

Chinese Spy Balloon: A New Kind of Aerial Threat?

Hello defence lovers! Recently a Chinese spy balloon was shot down by an American F-22 raptor after it violated American aerospace. In this article, we will discuss what threat these balloons pose to India’s national security and how we can deal with this threat.

What Is a Spy Balloon?

The balloon is one of the oldest flying objects created in the history of mankind. Today it has been adapted to perform various functions ranging from decoration to air travel. Among all these types, there is a specific type that is called a “weather balloon”. Weather balloons are designed to carry a payload of sensors. These sensors monitor different atmospheric parameters like pressure, temperature, air composition, etc. These sensors are powered by solar panels mounted with them. However, these balloons can be employed for spying roles by equipping sensors capable of monitoring and recording sensitive data. This may include instruments like electro-optical sensors for monitoring electromagnetic radiation of different spectra, synthetic aperture radars for terrain mapping, high-resolution cameras for taking photographs, etc. Before the invention of spy satellites, during the cold war era, these balloons were the principal tool for spying on enemy territories. These are generally made of high-flexibility latex material. Mostly hydrogen or helium is used to fill the balloons.

Why Chinese Spy Balloon Is a Threat?

As discussed above, spy balloons can be equipped with various surveillance equipment. In the age of satellites, spy balloons might seem irrelevant but these have some unique advantages over satellites. Satellites are very expensive assets. Developing and launching satellites require a large investment. Compared to a satellite a balloon is dirt cheap. A spy balloon can be used to collect sensitive data during any major military exercise without the fear of losing it. On the other hand, spy satellites can be positioned over a certain area but for a limited time only.

Since spy balloons are good and inexpensive spying tools China will use these at our northern borders to harass the radars and air defence systems. During any military engagement, hundreds of these balloons can be used to confuse and saturate the Indian radars. Thus we have to neutralize these balloons.

How To Neutralize?

Now let us discuss the methods which can be used to neutralize a spy balloon. Usually, these balloons fly at altitudes between 59,000 feet and 1,20,000 feet above sea level. These altitudes are beyond the maximum engagement altitudes of regular air defence systems.

Air Defence SystemMaximum Flight CeilingMaximum Range
Akash Air Defence System20km40km
Barak-8 (MR SAM)16km70km
SA 6 Kub7km20km
S-400 (40N6E Missile)30km400km
S-400 (48N6DM Missile)60km200km
Prithvi Defence Vehicle Mk-II1200km
Prithvi Defence Vehicle Mk-I150km
Advanced Air Defence (AAD)40km

Using Surface-to-Air Missiles

According to the table above, regular air defence systems such as Akash and Barak-8 are incapable of dealing with a spy balloon flying at a height of 20 kilometres (65,616 feet). Thus, only specialised air defence systems such as the S-400 system’s 40N6E and 48N6DM missiles, ballistic missile defence system missiles (PDV and AAD), and anti-satellite missiles (PDV Mk-II) can neutralise a spy balloon. These options are simply too expensive to be used to shoot down a low-cost balloon.

Using Fighter Jets

Thus shooting down a balloon with an advanced ground-based air defence missile economically does not make any sense. The Americans used the F-22 raptor to fire an AIM-9x missile to destroy the Chinese spy balloon. This method is the most economical method. However in this case the target was roughly at 65,000 feet. As these balloons are capable of going at altitudes above1,00,000 feet, let us look at the available options.

AircraftService ceilingRate of climb
Su-30 MKI56,800 ft59,000 ft/min
Rafale51,952 ft60,000 ft/min
Mig-2959,000 ft65,000 ft/min
Tejas53,500 ft
Mirage-200055,970 ft56,100 ft/min
Comparison of Service Ceiling of Fighters in the Indian Air Force

From the above table, we can see that the maximum service ceiling of all the fighter aircraft which are currently in service is less than 60,000 feet. The Service Ceiling is the altitude up to which the control surfaces of an aircraft work satisfactorily. To understand why this happens let us understand some basic flight physics. As we go up in the atmosphere the density of the air decreases along with the drag (resistance due to air friction). The lift generated by the wings of the aircraft depends upon the velocity of air passing over and below it along with the density and angle of attack. As velocity increases, lift increases. As density decreases, lift decreases. The control surfaces as horizontal stabilizers, verticle stabilizers, ailerons and canards will only work if they are able to produce sufficient lift. At the service ceiling, the lift produced by the control surfaces is just sufficient to keep the aircraft controllable. However, beyond the service ceiling controlling the aircraft becomes difficult.

Mig 29 Hitting its service ceiling

Now let us understand if 60,000 feet is the maximum service ceiling of most aircraft, the how a spy balloon at 100,000 feet can be neutralized. There is a technique called “Zoom Climb”. In this technique, the aircraft climbs to around 40–45000 ft. The throttle is jammed at maximum engaging the afterburners. Then a steep climb is made until the aircraft starts losing lift and begins to stall. On December 6, 1959, the XF4H, a prototype of what would become the F-4 Phantom, reached 30,940 meters (98,000 ft) in a zoom climb. On 25 July 1973, Aleksandr Fedotov reached 35,230 m (115,600 feet) in a MiG-25 with a 1,000 kg payload and 36,240 m (118,900 feet) with no load. This is a world record even today.

Now that we have discussed the altitude, let us discuss the weapons which can be used to deal with the threat. At a such high altitude, the amount of oxygen is very limited. It might be a problem for the engines but it is not a problem for most of the air-to-air missiles as most of them are powered by solid rocket motors. The problem comes from controlling the missile. The Beyond Visual Range missiles are generally controlled by control surfaces, which will definitely not work at such altitudes. However, short-range Within Visual Range (WVR) missiles often come with thrust vectoring control for improved manoeuvrability at close range. Hence these missiles can be an ideal choice for shooting down spy balloons. We should note that the F-22 raptor used AIM-9X which is a WVR missile with thrust vectoring control.

Using Air-Launched Anti-Satellite Missiles

In 1978, the United States Airforce began the development of a miniature anti-satellite weapon that can be launched from a fighter aircraft. This resulted in the development of the ASM-135 Anti_satellite missile. It could be launched from an F-15 with the help of the “Zoom Climb” technique discussed earlier. This missile had a maximum flight ceiling of 563km. The missile used AGM-69 air-to-ground missile as the base, which was powered by two additional solid rocket engines.

In the early 1980s, the Soviet Union also started developing a counterpart to the US air-launched ASAT system, using modified MiG-31D ‘Foxhounds’ as the launch platform. The system was called 30P6 “Kontakt”, the missile used is 79M6.

A similar approach can be followed by DRDO, to convert one of our existing missile systems into an air-launched anti-satellite weapon. Moreover, we need this weapon for specifically neutralizing Chinese spy balloons, so a flight ceiling of 50 km would be more than enough.

Using Directed Energy Weapons

The Soviets first came up with the concept of ground-based directed energy weapons for neutralizing enemy satellites. Allegedly the Soviets developed the prototype of their ASAT laser weapon and deployed it at Terra-3. Later it is believed that the project was abandoned after the ballistic missile treaty was signed.

DRDO and BARC have been developing the KALI series of electron accelerators from late 1980 onwards. The Kali-5000 is believed to have significant directed energy weapon capabilities. According to the information available in the public domain, Kali is being used to test the electromagnetic attack resistance of our satellites. Hence we can draw the conclusion that it can be used to attack balloons flying at 1,00,000+ feet and destroy their onboard sensors. However, project Kali is one of the most classified projects. It may be much more capable than we are assuming it to be.


In the above section, we learned how a very cheap and primitive balloon could be a headache for the country’s air defence. The easiest way of neutralizing the threat is not very economical and the most economical way is not the easiest way. Thus to deal with Chinese spy balloons we also have to send our spy balloons over Chinese territory because the only question is not “will China use them against us?” but “when will China use them against us?”


Sheershoo Deb

I am a defense aspirant preparing to be an officer in the prestigious Indian armed forces. Earning the prestigious blue uniform is my dream.

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