ISRO’s Spectacular Quantum Jump On Free-Space Communication

Lalit Koundaal


Quantum Communication has attracted researchers from physics, mathematics & computer science since 1984 and 1991 when the first protocol for quantum cryptography came into existence.

Indian Space Research Organisation (ISRO) late last week (19 Mar 2021) went ahead in demonstrating free-space quantum communication over a distance of 300 meters. The demonstration took place at Space Application Centre (SAC), Ahmedabad between two buildings having a clear line of sight (i.e obstruction-free).


In this age of top-notch technologies, the internet and smartphone revolutionizing the entire world, every now & then there are reports of news on mega hacks, of losing a huge amount of sensitive pieces of information.

There are threats posed by cyberattacks and Governments, regulatory authorities, Militaries, aerospace companies, and business houses are all wanting to have more secure ways of transmitting the information.

Today, the sensitive data is typically encrypted and then sent across fiber-optic cables with digital keys. Now, the hackers can always hack the data without leaving a trace.

Quantum communication has taken the advantage of the laws of quantum physics to safeguard data. These laws allow particles, typically photons of light, known as quantum bits or qubits for data transmission.

The hackers are going to find it difficult to steal information because the super-fragile quantum starts collapsing to either 0 or 1, sending alert signals and transmission of information would be stopped immediately.

Some companies have created networks for transmitting highly sensitive data based on the process called Quantum Keys Distribution, or QKD. These networks are called ultra-secure.

IRSO’s Quantum Jump

Indian Space Research Organisation(ISRO) demonstration on free-space quantum communication is major mile-stone development for unconditionally secured satellite data communication using quantum technology.

To avoid interference from direct sunlight, the experiment was conducted at night. The live videoconferencing using quantum-key-encrypted signals was also part of the demonstration.

Many key indigenously developed technologies which included ‘NAVIC’ receiver for time synchronization between the transmitter and receiver modules and gimbal mechanism systems instead of bulky large-aperture telescopes for optical alignment were used to accomplish this major feat.

IRSO  plans to extend the Quantum Key Distribution (QKD) technology to satellites and call it Satellite-Based Quantum Communication (SBQC). To do so IRSO is gearing up to demonstrate the technology between two Indian Ground Stations.

Government Of India initiatives

India’s Department of Science & Technology has set up a program called Quantum-Enabled Science & Technology (QuEST). This is being described as Phase 1 of India’s quantum computing program. The country will be laying out the basic infrastructure that is needed to promote research in this field and will infuse a sum of Rs 80 Crore in three years to help & put the research on a fast track.

The government of India believes this will help in improving the state of national security as quantum-level encrypted information becomes a common communication standard.

Under this flagship program, researchers from institutions such as the Indian Institute of Science (IISC), the Indian Space Research Organisation, and Tata Institute of Fundamental Research, are working on quantum computing and allied areas, including quantum-safe cryptography and quantum communication.


Amongst its plentiful fascinating attributes, quantum communication has the potential to achieve secure communications at confidence levels, simply unattainable in classical communications settings. This is because quantum physics introduces a range of phenomena that have no counterpart in the classical domain, such as quantum entanglement and the superposition of quantum states.

The next communication experiment from ISRO is not going to be for 300 meters but a full-fledged experiment using satellites and a compatible set on the earth which is sure to herald a new era in technology advancement.

The space applications programs are not to conquer the vast space around us, but to safeguard the earth where we live and make future communications hack-proof & eavesdrop-proof.



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