A Chinese rocket is about to crash into Earth. The newly added Wentian lab in Tianhe module.

  The Tianhe module was launched by the China National Space Administration last year. The module remained in space alone as the Chinese space station until July 24. But on the morning of July 25, only Mir and the International Space Station remained as space stations consisting of several Chinese space station modules, with the Wentian Laboratory module attached to the Tianhe module. Now China has also developed to that level.

A photo taken from the Chinese space station

    Launched on April 29, 2021, the Tianhe module is in an orbit 390 km high, inclined 41.5° to the equator. The module spent 12 and 6 months on Shenzhou alone. But when the new team of astronauts who arrived on Shenzhou 14 on June 5 leaves the station after 6 months, the station will not remain a single module. That's because of the newly added Wentian lab module and the Mengtian lab module added in October.

    The Wentian ("Quest for the Heavens") lab module is a 17.9 m long, 4.2 m diameter module with a mass of 22,000 kg. This includes equipment and facilities for conducting scientific experiments in various fields. It is possible to conduct various tests not only in the module but also outside the module. Experiments that need to be exposed to the vacuum and radiation of space can thus be stored.

    When the solar panels of the Wentian module are opened, the total width is only 55 meters. These large solar panels boost the station's electricity generation. In addition, an air lock (Airlock) used for astronauts to travel out of the station is included and a small robotic arm is also connected to the outside of this module.

    The Wentian module was launched by China's most powerful rocket, the Long March 5B. The mass of this 53.66 meter high rocket after filling with fuel is about 837,500 kg. This can launch about 25,000 kg into low earth orbit. Therefore, it becomes the third most powerful rocket in the world today. The 5m diameter first stage has two YF-77 engines powered by liquid hydrogen and liquid oxygen. These two engines work from launch to low Earth orbit and generate a thrust of about one million newtons.

    But these two engines alone are not capable of lifting the rocket from the ground. The rocket has 4 boosters for that. Fueled by purified kerosene (RP-1) and liquid oxygen, the YF-100 rocket engines have 2 boosters each and generate about 1.2 million newtons per engine. The rocket, powered by all these 10 engines, lifted off from the LC-101 launch pad at China's Wenchang Satellite Launch Center on July 24 at 11.52 am.

    About 3 minutes after launch, the last 4 boosters were jettisoned and after an 8-minute burn, the first stage entered low Earth orbit at 182 × 299 × 41.4 km. Then the Wentian module was released. The Wentian module, which lifted its orbit for 13 hours, was launched on the 25th in the morning. At about 12:43, Tianhe connected with the module's front connecting gate. This will then be transferred to either the right or left door.

Wentian module, astronaut Shenzhou 14, Tianhen module and cargo Tianzhou 4.

    The abandoned rocket's first stage is in an unstable low-Earth orbit. This phase, which slows down due to atmospheric drag, may cause a small amount of remnants to reach the ground during uncontrolled entry into the Earth's atmosphere in a few weeks. The first Long March 5B rocket, launched in 2020, entered the atmosphere without control in this way and some of the remaining parts crashed in the Ivory Coast state.

    The first stage of the second Long March 5B rocket that launched the Tianhe module crashed into the Indian Ocean southwest of Sri Lanka. It is not yet known where the first stage of the rocket will fall this time. It is not yet known where the first stage of the rocket will fall this time. However, the probability that part of a rocket stage entering the atmosphere will harm you is negligibly small.

A red box indicates the first phase to collapse

    Mengtian module will be launched in October after Wentian module. In addition, China is preparing to add another important part to the station. Although it is said to add, this part is connected to the station from time to time. It will remain in orbit for a longer time and will be included in the orbit of the Chinese Survey Space Telescope (CSST) which will be launched in 2023. This is occasionally associated with the station for repairs and maintenance.

    The telescope has a 2-meter diameter mirror and a 2,500-megapixel camera. The 15.5-tonne space telescope will be launched on a Long March 5B rocket, along with the station's modules. Chen Dong, Liu Yang and Cai Xuzhe, who arrived on the station in June, supervised the docking of the Wentian module and will also carry out the docking of the Mengtian module during their mission. Until now, a group of astronauts went to the station only after the previous group had reached Earth. But not anymore. As with the International Space Station, the current team will depart for Earth after the arrival of the new team of astronauts.

Chinese space station after all 3 modules are properly installed