Chinese space station space puzzle, comparison of the three cabins of Tianhe, Wentian and Mengtian

The last day of golden October was destined to be a critical day. The Mengtian experimental module was launched into space as scheduled, which meant that the basic construction phase of the Chinese space station ushered in the last main module, and the iconic T-configuration Chinese space station CSS first appeared in space.

● Launch overview

●Launching process

This time, the Long March 5B with the rocket serial number of Yao-4 was launched from the No. 1 station LC101 of the Wenchang Space Launch Center in Hainan, China's southernmost space launch site. LC101 is dedicated to the Long March 5/B rocket launch; LC201 is dedicated to the Long March 7/Long March 8 rocket. At 15:37 Beijing time on October 31, 2022, China's most powerful rocket in service, the Long March 5B, rose majestically, shaking the sky and the earth. After 17 seconds, the rocket body began to turn southeast; about 177 seconds after the launch, the four boosters separated from the main rocket; about 223 seconds after the launch, the 20.5×5.2-meter large fairing separated; 8 minutes after the launch, the two engines of the main rocket were shut down, and then the main rocket and Mengtian were separated for 5 seconds; after a series of operations, it gradually entered the low-Earth orbit, and the docking target was aimed at the Tianhe core module at an altitude of 390 kilometers and an equatorial inclination of 41°. About 13 hours after the launch, the orbital rendezvous and docking was carried out, and the Mengtian experimental module docked with the forward port of the Tianhe core module. At that time, the three astronauts (Chen Dong, Liu Yang, and Cai Xuzhe) who were carrying out the Shenzhou XIV flight mission on the space station will participate in and witness the entire docking process. This is also the second time that the Chinese space station has launched and docked the main module with astronauts after the launch and docking of the Wentian. The Mengtian experimental module is the finale of the basic configuration of the Chinese space station. The three major on-orbit modules: the Tianhe core module + the Wentian experimental module + the Mengtian experimental module form a landmark T-shaped combination, which means that the Chinese space station is basically formed. The total mass of the Chinese space station, which has just appeared in space, is as high as 91 tons, making it the largest spacecraft combination currently in orbit in China.

●Mengtian Experimental Module

This is the second experimental module of the Chinese space station and the third largest module of the Chinese space station. The experimental module has a diameter of 4.2 meters and a length of 17.9 meters, which is the same size as the Wentian module and is comparable to a bus. The launch mass is about 23 tons, and the pressurized space is also 110 cubic meters, but the astronaut activity space is reduced to 32 cubic meters, which is smaller than the 50 cubic meters of the Tianhe module and the Wentian module, and is mainly used by the storage area. The Mengtian module consists of four modules: the working module, the payload module, the cargo airlock module, and the resource module. Together with the Wentian module, it forms two symmetrical modules of the Chinese space station. Like the Wentian module, the Mengtian module is equipped with a large flexible solar power generation array, with a full wingspan of about 56 meters and a double wing area of ​​276 square meters. The average daily power generation exceeds 430 degrees, which is enough to meet the needs of a series of scientific research experiments in the future. The Mengtian module also has the function of automatic entry and exit of payloads and the release of micro-aircraft. It is also equipped with an extravehicular deployment test platform to meet the special needs of some payloads that need to be exposed to space. What is more worth mentioning is that the Mengtian experimental module carries the world's first set of space cold atomic clocks consisting of hydrogen clocks, rubidium clocks, and optical clocks. The goal is to reach an ultra-low temperature of 10 picokelvins, which is expected to break the lowest temperature record ever created by mankind, surpassing similar experiments conducted by NASA on the International Space Station. In this way, the time and frequency system with the highest frequency stability and accuracy in space will be built, which will help cutting-edge scientific research such as gravitational redshift and fine structure constant measurement.

● Similarities and differences among the three cabins of Mengtian, Wentian and Tianhe

How are the three cabins of Mengtian, Wentian and Tianhe distinguished? What are their similarities and differences? How are the responsibilities divided? See the comparison table below for details▼

Mengtian and Wentian are both experimental cabins, but each cabin has its own merits. Mengtian focuses on physical experiments and material science experiments, so we might as well regard it as a physical laboratory. Therefore, it is equipped with 13 scientific experimental cabinets such as fluid physics, basic physics, material science, combustion science, and aerospace technology experiments, and 37 extravehicular payload interfaces. Wentian focuses on life science experiments, so we can regard it as a life science laboratory. Therefore, it is equipped with experimental cabinets such as life ecology, biotechnology, and variable gravity science, which can support the research on the response mechanisms of growth, development, genetics, aging, etc. of various types of plants, animals, microorganisms, etc. under space conditions, as well as experimental research on closed ecosystems. The biggest difference between the Tianhe core cabin and the two experimental cabins is that it is the management and control center of the Chinese space station, providing power, propulsion, and life support systems for the space station; as well as docking and docking experimental cabins, manned spacecraft, and cargo spacecraft. Of course, the Wentian experimental cabin and the Tianhe core cabin are backups for each other, and the key platform functions are consistent, which can fully cover the working requirements of the space station assembly. In other words, when Tianhe is on vacation, Wentian can take over the work. It is an all-rounder that integrates platform functions and test payload functions.

●Subsequent tasks

With the first experimental module Wentian and the second experimental module Mengtian docking with the Tianhe core module, a T-shaped assembly is formed, which means that the Chinese space station is basically formed. The Chinese Space Station (CSS) built this year is a basic model (mass reaches 91 tons, close to 100 tons, equivalent to 1/5 of the International Space Station). The big show after Mengtian is the Sky Survey Space Telescope. It is now planned to be launched in December 2023, operate independently in the same orbit as the Chinese space station, and dock with it when maintenance is required. It will be put into scientific observation around 2024.
The Survey Space Telescope, also known as the Survey Space Telescope and the Survey Optical Cabin, can be said to be one of the components of the Chinese space station and China's first large-scale astronomical telescope in extraterrestrial space. The telescope has a diameter of 2 meters and a mass of 15.5 tons. It will fly in the same orbit as the Chinese space station for a long time, with a mission period of more than 10 years. The Survey Module is a space telescope that occupies the most observation time. It is a camera with an extremely wide field of view, with a field of view of 1.1x1.2 square degrees. With imaging quality comparable to that of the Hubble Telescope, the Survey Telescope's field of view can reach 300 times that of the Hubble Telescope. During the entire survey cycle, the Survey Module will cover an area of ​​17,500 square degrees, accounting for 40% of the entire sky area, and is expected to accumulate high-quality data on nearly 2 billion galaxies. This will be the most advanced and expensive research facility ever deployed by the Chinese astronomical community, and is expected to bring mankind a new understanding of the universe.

●Future Chinese Space Station

The Chinese space station built this year is a basic type - T-shaped. In the future, the scale of the Chinese space station will be expanded to a "干" shape: one more core module, two experimental modules, and a manned spacecraft will be stationed there for manned transportation and emergency return of astronauts. The maximum scale can reach 180 tons. If it reaches such a scale, landing on the moon, building a lunar base, landing on Mars, and flying to the farther Jupiter are no longer far away, and some plans have even been realized in parallel. At the same time, the International Space Station (ISS) led by the United States has extended its service life from 2024 to 2030. If the planned world's first commercial space station (Axiom Space Station) is successfully built, it will also be put into operation in 2024 and replace the International Space Station from 2030. In addition, Russia will set up its own portal in 2024, split from the International Space Station, and operate the Russian Orbital Space Station (ROSS) alone. This means that in the future, there will be four space stations operating in parallel in the low-Earth orbit above our heads: the International Space Station ISS, the Chinese Space Station CSS, the Axiom Station, and the Russian Space Station ROSS.