Besides Mozi, what other satellites are used for scientific experiments?

The experimental satellite of quantum science plays an important role, that is, quantum secure communication. After all, national security is really safe. If our country's communication is stolen by some hackers with ulterior motives, the consequences will be unimaginable. Therefore, the use of quantum secure communication increases the security of information to a certain extent. This is its advanced point.

In 1950s, one of the earliest discoveries of mankind when he went out of the earth to explore space was the geomagnetic circle outside the earth's atmosphere. The geomagnetic circle is like an umbrella, which blocks the high-speed particles ejected by the sun, prevents charged particles from flowing to gas molecules in the atmosphere to transfer energy, and makes gas molecules unable to escape the gravity of the earth. Without this umbrella, the earth would be like Mars, the atmosphere would be blown away by the solar wind, and liquid water would not be preserved. When the sun is violently active, the energy from the solar wind will pass through the geomagnetic umbrella and be released in the geomagnetic circle, resulting in the phenomenon of violent explosion of various energies, which is called "space weather". Different from the traditional concept of "weather", space weather is the concept of environmental change in near-earth space, involving space plasma, magnetic field, radiation and other phenomena. In the solar system, space weather is mainly influenced by the wind speed and density of solar wind and the interplanetary magnetic field brought by solar plasma.

The threats and harms caused by space weather to human life are various, which will affect communication, satellite, navigation, astronaut activities and scientific and technological facilities on the ground and in space. Historically, strong space weather has caused many satellites to fail, which has caused the interruption of communication and ground power grid, which has greatly affected the measurement and operation of spacecraft. With the increasing dependence of modern society on space high-tech facilities, it is urgent to understand and master space weather. Now, it has been more than half a century since mankind entered the space age, but the process of space weather is still a mystery. SMILE satellite will use a new method combining soft X-ray and field detection to "photograph" the magnetosphere of the earth and guide us to uncover the mystery of space weather process.

In addition, Smile satellite adopts elliptical orbit with large inclination angle, and its extreme ultraviolet imager has better accuracy, lower threshold and better sunlight suppression. Together with X-ray imaging, in-situ measurement of magnetic field and plasma, it will bring an innovation to the research of solar-terrestrial space physics and play a direct role in predicting and mitigating space weather disasters.