The Chinese have launched the first satellite that can achieve quantum communications between space and Earth. The launch of the Quantum Science Satellite – called Mozi – took place at 17:40 UTC on Monday using a Long March-2D (Chang Zheng-2D) launch vehicle from the 603 Launch Pad of the LC43 complex at the Jiuquan space center.
The new satellite is dedicated to quantum science experiments. The Quantum Space Satellite, (or Quantum Experiments at Space Scale) will test the phenomena of quantum entanglement.
Operated by the China Academy of Sciences, this 500 kg satellite – announced as the name “Mozi” in honor of a fifth century BC Chinese scientist – contains a quantum key communicator, quantum entanglement emitter, entanglement source, processing unit, and a laser communicator.
QUESS will relay transmissions between two ground stations (one in China, and the other in Europe) transmitting quantum keys.
During the mission, Chinese scientists will implement a series of science missions between the satellite and quantum communication ground stations.
QSS will operate on a Sun-synchronous circular orbit with an altitude of 600 km.
One of the major objectives of the mission is to set a Quantum Key Distribution from satellite to ground, setting 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.
The mission will also create a global-scale quantum communication network, establishing 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.
It will also test the Quantum Entanglement Distribution from satellite to two ground stations in China and in Europe, creating 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.
The Austrian Academy of Sciences provided the optical receivers for the European ground stations.
Finally, the QSS plans to achieve 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.
The Quantum Science Satellite consists of several different subsystems: the attitude control subsystem, power subsystem, thermal control subsystem, telemetry and command subsystem, communications subsystem, structure subsystem, and housekeeping subsystem.
In order to design the Quantum Science Satellite, the mission activities, requirements, and mission analysis have been completed at the end of 2011.
Mission definition and justification and key technique research were finalized by the end of 2012. Detailed definitions of the spacecraft were completed in March 2013.
Prototypes of on board devices and components were been built for verification and have been checked and approved at the end of August 2013. Electronic characteristic tests on the prototypes were carried out by the end of September 2013.
After that, in October 2013, the structural prototype of the satellite was assembled and the mechanical environmental simulation tests have been completed.
Subsequently, the thermal balance tests were finalized in December 2013 on the thermal characteristic prototype of the satellite.
At the end of October 2013, some prototypes of on board devices, which are designed for qualification tests, were put into production and were checked and accepted by the end of March 2014. The satellite arrived at Jiuquan on July 8, 2016.
The payload of the quantum science experimental satellite includes quantum key communicator, quantum entanglement emitter, quantum entanglement source, quantum experiment controller and processor and high-speed coherent laser communicator.
The key techniques of the optical communication terminal consist of high precision tracking and pointing, wide-band high-extinction ratio polarization-maintaining capabilities and the aviation engineering of quantum entanglement source.
Developed by the Chinese Academy of Sciences (CAS), the Quantum Science Satellite is part of China’s Strategic Priority Program on Space Science.
The first satellite of this program, a dark-matter satellite, was launched into space in December. The second, the country’s first microgravity satellite, the SJ-10, was successfully launched on April 6.
A hard X-ray telescope for black hole and neutron star studies is also expected to be launched in the second half of this year.
The launch also included a Spanish passenger in the form of a 6U CubeSat “³Cat-2” from the NanoSat lab at Universitat Politècnica de Catalunya, classed as “a novel GNSS-R payload for Earth observation”.
Launch Vehicle and Launch Site:
The Chang Zheng-2D launch vehicle is a two-stage rocket developed by the Shanghai Academy of Spaceflight Technology. With storable propellants is mainly used to launch a variety of low earth orbit satellites.
The development of CZ-2D began in February 1990. From 2002, to meet the demand of SSO satellites, the payload fairing of 3350mm in diameter and attitude control engine for the second stage have been successfully developed; and the discharge of remaining propellant and de-orbit of the second stage have been realized.
This launcher is mainly used for launching LEO and SSO satellites.
The CZ-2D can launch a 1,300 kg cargo in a 645 km SSO. The rocket is 41.056 m long and the first, second stages and payload fairing are all 3.35 m in diameter.
Its first stage is the same of the CZ-4 Chang Zheng-4. The second stage is based on CZ-4 second stage with an improved equipment bay. Lift-off mass is 232,250 kg, total length 41,056 meters, diameter 3.35 meters and fairing length 6.983 meters. At launch, it develops 2961.6 kN engine thrust.
The first stage has a 27.91 meter length with a 3.35 meter diameter, consuming 183,200 kg of N2O4 / UDMH (launch mass of the first stage is 192,700 kg). Equipped with a YF-21C engine capable of a ground thrust of 2,961.6 kN and a ground specific impulse of 2,550 m/s. Burn time is 170 seconds.
The second stage has a 10.9 meter length with a 3.35 meter diameter, launch mass of 39,550 kg and consuming 45,550 kg of N2O4 / UDMH. Equipped with a YF-24C cluster engine with a main engine vacuum thrust of 742.04 kN and a vernier engine with a vacuum thrust of 47.1 kN (specific impulses of 2,942 m/s and 2,834 m/s, respectively).
The CZ-2D can use two types of fairings depending on the cargo. Type A fairing has a 2.90 meters diameter (total launch vehicle length is 37.728 meters) and Type B fairing with a diameter of 3.35 meters – total launch vehicle length is 41.056 meters.
The first launch of the CZ-2D was on August 9th, 1992 from the Jiuquan Satellite Launch Center orbiting the Fanhui Shei Weixing FSW-2-1 (22072 1992-051A) recoverable satellite.
The Jiuquan Satellite Launch Center, in Ejin-Banner – a county in Alashan League of the Inner Mongolia Autonomous Region – was the first Chinese satellite launch center and is also known as the Shuang Cheng Tze launch center.
The site includes a Technical Centre, two Launch Complexes, Mission Command and Control Centre, Launch Control Centre, propellant fuelling systems, tracking and communication systems, gas supply systems, weather forecast systems, and logistic support systems.
Jiuquan was originally used to launch scientific and recoverable satellites into medium or low earth orbits at high inclinations. It is also the place from where all the Chinese manned missions are launched.
The LC-43 launch complex, also known by South Launch Site (SLS) is equipped with two launch pads: 921 and 603.
Launch pad 921 is used for the manned program for the launch of the Chang Zheng-2F launch vehicle (Shenzhou and Tiangong). The 603 launch pad is used for unmanned orbital launches by the Chang Zheng-2C, Chang Zheng-2D and Chang Zheng-4C launch vehicles.
Other launch zones at the launch site are used for launching the Kuaizhou and the CZ-11 Chang Zheng-11 solid propellant launch vehicles.
The first orbital launch took place on April 24, 1970 when the CZ-1 Chang Zheng-1 rocket launched the first Chinese satellite, the Dongfanghong-1 (04382 1970-034A).