SpooQy-1 Nanosatellite Brings Gains in Space for Privacy and Computing Power
Entangled quantum signals generated aboard a 2.6 kg nanosat in low earth orbit herald the possibility of hack-proof computer networks.
A team led by researchers at the National University of Singapore's Centre for Quantum Technologies (CQT), has succeeded in building a tiny CubeSat that it has dubbed the SpooQy-1. The miniature satellite has demonstrated the ability to generate entangled quantum signals from within its diminutive package. The results of the project were published in the journal Optica.
Entanglement is a very odd aspect of quantum physics. If two particles are entangled, and one is observed, there will immediately be a change in its partner's properties. Einstein himself described the phenomena as "spooky action at a distance."
Spooky or not, this strange property may well serve as the basis of a hack-proof quantum internet.
The SpooQy-1 nanosat built by CQT. Image credited to CQT
Quantum Encryption
The concept of quantum encryption is based on the quantum mechanical phenomena of entanglement. Entangled photons, once generated, will always share certain properties, no matter how far separated they.
This is the basis of quantum key distribution (QKD), the generation of a secure cryptographic key. Reading the key disturbs the photons' entangled state, and the change is easily observed, so the rightful recipient of the key knows the key is compromised.
SpooQy-1 features a quantum source that creates pairs of entangled photons. Today's internet is built around the use of photons to carry data through fiber optic cables. The issue standing in the way of practical quantum internet is the optical losses in cable, limiting the distances over which entangled photons can travel to under 100 km.
Hence the interest in implementing quantum encryption in space-based systems.
Establishing Networks
Singapore could be served with a fiber-based quantum network, due to its small land area. But satellites are seen as the key for world-wide hack-proof networks. According to Alexander Ling, the lead at CQT's satellite program, "We are seeing a surge of interest in building quantum networks worldwide. Satellites are a solution to making long-range networks, creating connections across country borders and between continents."
The Chinese Micius satellite has established transmission of QKD signal from space to ground stations separated by 1,120 kilometers. However, this demonstration project has only achieved a secret-key rate of 0.12 bits per second.
SpooQy-1 is the small object in the center of the picture, seen as it was launched from the International Space Station. Image credited to NASA
Going Small: CubeSats
SpooQy-1 is built to the growingly popular CubeSat specification. CubeSats are built on standard unit sizes of 1.33 kg and one liter (10 x 10 x 10 cm) in volume. SpooQy, weighing 2.6 kg, can be said to be of two units (2U) size. Micius, by contrast, weighs 630 kg.
There are enormous advantages to CubeSats. The tiny weight and size mean that they can, and have been, launched in volume, and if one fails, others are in place to replace it. The standardization of their design has made it possible for standardized deployment capabilities to have been developed. SpooQy-1 itself was launched from the international space station.
Next Steps
SpooQy-1's handlers haven't as yet attempted to send its quantum signals to Earth. That's the next phase's goal, which will involve a collaboration between the CQT researchers and their SpeQtral offshoot with the UK's RAL Space.
According to Robert Bedington, Chief Technology Officer at SpeQtral, "In our next mission, we are working towards CubeSat-to-ground quantum communications for sharing secret encryption keys across the globe. This capability is attractive to organizations who need to keep their networks secure from the most sophisticated hackers."
