China recently launched the first-ever quantum satellite. The satellite is named “Micius“.
- Many countries are working on quantum communications, including fiber-optic quantum key distribution networks in the United States, Europe, and China. However, China is the first one to launch a satellite to develop the complex technology.
- The 500 kg satellite contains a quantum key communicator, quantum entanglement emitter, entanglement source, processing unit, and a laser communicator. A rocket named the Long March-2D launched the satellite into space. The launch site was in China’s northwest Gobi Desert.
- The satellite is built to circle Earth at an altitude of around 310 miles (500 km) and complete one lap every 90 minutes.
Aims of this mission:
- It is a proof-of-concept mission designed to facilitate quantum optics experiments over long distances to allow the development of quantum encryption and quantum teleportation technology.
- The satellite’s two-year mission will be to develop ‘hack-proof’ quantum communications, allowing users to send messages securely and at speeds faster than light.
- The scientific goals are to implement a series of science missions between Quantum Science Satellite and quantum communication ground stations.
The major tasks are as follows:
Quantum Key Distribution from Satellite to Ground: To set up an ultra-long-range quantum channel between ground and satellite with the assistance of high-precision acquisition, tracking and pointing system, implement a quantum key distribution between the satellite and the ground stations, and carry out unconditional secure quantum communication experiments.
Global Scale Quantum Communication Network: To set up a real wide-area network for quantum communication using the satellite repeater and two arbitrary quantum ground stations and their auxiliary local-area fiber quantum networks.
Quantum Entanglement Distribution from Satellite to two ground stations: Distribution of quantum entangled photons from the satellite to two distant ground stations whose distance is larger than one thousand kilometers; test of the entanglement properties at a large scale and nonlocality of quantum mechanics.
Quantum Teleportation from Ground to Satellite: as a totally new way of communication, quantum teleportation is the fundamental process of quantum networks and quantum computing. A high quality quantum entanglement source on the ground will be built to achieve ground-to-satellite teleportation experiments based on photon entanglement.
Significance of this launch:
This is an attempt to develop a hack-proof communications system. During its two-year mission the space object will transmit un-hackable encryption keys from outer space to the Earth’s surface. If the experiment works it could solve the main problem of distributing encryption keys that cannot be stolen. That would result in hack-proof communications.
It will also provide new knowledge about quantum entanglement. That happens when pairs or groups of very tiny particles are made or work together so the quantum state of each particle is part of a whole system.
How the satellite operates?
QUESS will use entangled photons via a special laser to transmit messages to ground stations in China and Austria. In theory such systems are safe from hack attacks. An attempt to intercept an encryption key would cause a change in the photons’ state that could be picked up.
- The special kind of laser has several curious properties, one of which is known as “the observer effect” – its quantum state cannot be observed without changing it.
- So, if the satellite were to encode an encryption key in that quantum state, any interception would be obvious. It would also change the key, making it useless.
- Highly complex attempts to build such a “hack-proof” communications network are based on the scientific principle of entanglement.
What Is Quantum Entanglement?
Quantum entanglement is one of the central principles of quantum physics. In short, quantum entanglement means that multiple particles are linked together in a way such that the measurement of one particle’s quantum state determines the possible quantum states of the other particles.
- This connection is independent of the location of the particles in space. Even if you separate entangled particles by billions of miles, changing one particle will induce a change in the other. Even though quantum entanglement appears to transmit information instantaneously, it doesn’t actually violate the classical speed of light because there’s no “movement” through space.
- It is hence difficult to wiretap, intercept or crack the information transmitted through it.
So what exactly is a quantum-enabled satellite?
It contains a laser that transmits a pair of entangled photons – minuscule sub-atomic particles of light – down to two separate base stations.
- One half of the pair goes to one base station, the other to the second.
- These photons suffer from something known as the ‘observer effect’, which means that the moment anyone tries to intercept them, their quantum state is immediately changed.
What are the applications?
In the face of ever more powerful hacking and surveillance – which could one day also include powerful quantum computers – the security of commercial communications is also increasingly important. Hence, Quantum computing is largely seen as the next big thing in communications. The technology has applications for precision in everything from healthcare to industrial production.
Cybersecurity has been a major focus in recent years for China. Quantum messaging could become a major defense against hackers and have applications ranging from military and government communications to online shopping.