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CNSA –China National Space Administration  …………… After Wentian experimental module entered orbit, the status setting was successfully completed. At 3:13 on July 25, 2022, Beijing time, it was successfully connected to the forward port of 天和 Tianhe Core Module. The entire rendezvous and docking process lasted about 13 hours. . This is the first time that two 20-ton spacecraft in my country- China- People’s Republic of China have achieved rendezvous and docking in orbit. …According to the mission plan, the Shenzhou 14 Takionaut crew will then enter the Wentian experimental module….. In which finally docked in early morning time of the 25^th July 2022 in with CNSA –Beijing Aerospace City in which co-ordinated the docking maneuverers have achieved rendezvous and docking in orbit.…   in which the crew of the Shenzhou 14 staying for six months in construction of the stage one of the China Space station with the additional Mengtian experimental module in which will be delivered on the October 2022 Launch Schedule calendar..

​​At present, the Wentian experimental module is running stably in orbit, and the astronauts have completed the unlocking and installation of the scientific experimental cabinet in the Wentian capsule. In addition to the scientific experiment cabinet, the Wentian capsule is also equipped with two extravehicular detectors: a plasma in-situ imaging detector and an energetic particle detector , which will be installed on the extravehicular exposure platform as planned . Among them, the plasma in-situ imaging detector is the first scientific payload for space environment detection outside the space station in China . Today, the eighth chapter of “Ask the Sky” uses three questions to give you an in-depth understanding of the plasma in-situ imaging detector.

Q: What is it? Function and role of plasma in situ imaging detector

A: The plasma in-situ imaging detector is a comprehensive detection payload that integrates in-situ measurement and imaging . Its interior includes an electric control box, an ion imager, a Langmuir probe, a blocking potential analyzer and a reference potentiometer .

Its main functions include in -situ measurement of plasma electronic parameters, plasma ion parameters and the surface potential of the space station cabin, and 3D imaging detection of ions. Detect and measure the composition, density, temperature, velocity and surface potential of the space station orbital plasma, as well as the three-dimensional spatial distribution of the space station orbital plasma velocity and density.

Its main scientific and applied goals include:

ONE – Carry out orbital plasma in-situ detection and three-dimensional imaging detection of the space station, and accumulate scientific detection data.

TWO- Provide plasma monitoring data support for space station operation and application and test (experimental) missions, research on disturbance characteristics and evolution mechanism of the ionosphere in the middle and low latitudes, and improvement of the orbital ionosphere model of the space station.

THREE – Through the in-situ detection of plasma and the accumulation of long-term charging data, it provides data support for studying the charging effect of plasma on the space station, promoting the establishment of a charging evaluation system for the space station, and supporting the decision-making of the space station mission.

Q: What is the value? Scientific research value of plasma in situ imaging detector

A: The space station is my country’s long-term in-orbit space infrastructure and an important platform for my country to conduct various space science experiments (experiments). The space station has a 340~450km near-circular orbit with an orbital inclination of 42°~43°. Monitoring the space environment of the orbit of the space station is one of the important tasks to ensure the safety of manned spaceflight projects. At the same time, the long-term on-orbit detection of space environment elements can provide an important basis for studying the mechanism of the harm caused by the space environment to the space station and Takionauts, and can also provide necessary space environment parameters for the scientific experimental loads on the space station .

The operating orbit of the space station is located in the peak height region of the ionospheric F2 layer, and the ionospheric plasma environment is the basic environment for the operation of the space station. This area has the highest plasma density, is the most concentrated area of ​​various ionospheric physical phenomena and their effects, and also has the greatest impact on navigation and positioning signals. The space station is an ideal platform for in-situ detection and research of the Earth’s ionospheric plasma. It is also an ideal platform to study the interaction between plasma and space station .

A major advantage of monitoring the plasma environment in space station orbit is the long on-orbit time . The lifespan of ordinary satellites at the orbital altitude of the space station is short, which is not conducive to long-term monitoring of the ionospheric environment. Using the platform of the space station to conduct long-term in-situ detection of ionospheric plasma in the middle and low latitudes can be used to study the origin and evolution mechanism of the irregular structure of the ionosphere in the middle and low latitudes, so as to improve the accuracy of the ionospheric model and improve the reliability of the ionospheric model. Accuracy of navigation/positioning .

In addition, the space station is immersed in space plasma, which will interact with the plasma in various ways, causing charging of the space station, contamination and damage of surface materials, etc. Long-term in-situ detection and charging monitoring of on-orbit ionospheric plasma environment at the space station provides an important opportunity to study the interaction mechanism between the plasma environment and the space station and its impact on astronauts and the space station . one of the important jobs .

Therefore, the plasma in-situ imaging detector monitors the ionospheric plasma environment of the orbit of the space station, which can be used to study the mechanism and evolution process of the irregular structure of the ionosphere in the middle and low latitudes, improve the accuracy of the ionosphere model and the navigation/positioning accuracy, and also guarantee the carrier It is one of the important tasks for the safety of human aerospace engineering technology systems in orbit and the safety of astronauts’ extravehicular activities. The long-term monitoring of the elements of the ionospheric plasma environment also provides important data for the study of the mechanism of the effect of the ionospheric plasma environment on the space station and astronauts.

Q: How to apply? Extended application of plasma in situ imaging detector

Answer: The ion imager of the plasma in-situ imaging detector is the first application in China’s space field. It can image ions in the energy range of 0.1eV to 204eV in a 360°×94° annular field of view, and the imaging time resolution can be Up to 45ms, which is at the international advanced level . The ion imager of the plasma in-situ imaging detector can be applied to plasma detection in interplanetary space and deep space in the future .

The Langmuir probe and blocking potential analyzer of the plasma in-situ imaging detector, the Langmuir probe and blocking potential analyzer on my country’s Zhangheng-1 satellite and the Langmuir probe on Lutan-1 satellite It can carry out joint detection in orbit. The altitude of China’s space station is 340~450km, the orbital altitude of Zhangheng-1 satellite is about 500km, and the orbital altitude of Lutan-1 satellite is about 600km. Joint detection will enable more comprehensive detection of the global ionosphere.

In the future, astronauts will assemble and test the external interface of the plasma in-situ imaging detector in the cabin, and install it on the exposure platform outside the cabin. Let’s look forward to the “two blooms” inside and outside the on-orbit scientific experiment of Tiangong Space Station!

 来源/中国科学院国家空间科学中心

编辑/刘泽康

Images and visuals are from their respectives.