Much of Earth is relieved: this Saturday, July 30, the entire rocket stage must “return to Earth’s atmosphere” (understand: it will decompress). A few hours before the crash, we still don’t know exactly where it will fall on our planet. The 22-ton machine finally “returned” above the Indian Ocean at 6:45 p.m. The point of collapse and extent of debris impact is still unknown.

On Twitter, someone from Kuching, Malaysia tweeted a video showing the spread of the craft.

The rocket took off from China on July 24

On Sunday, July 24, China began construction on the second of three modules of its space station. The Wentian, weighing about 20 tons, was launched without an astronaut by a Long March 5B rocket from the Wenchang Launch Center on the tropical island of Hainan (south). The laboratory module, which is approximately 18 meters long and 4.2 meters in diameter, will be attached to Tianhe, the station’s first module, which will already be in orbit from April 2021.

The problem: The 22-ton stage of the rocket that brought Vendien was about to fall back to Earth after nearly a week in orbit. And no expert could say exactly where. According to the Aerospace Corporation, of the 22 tons, “only” 5 to 9 tons actually fall on our planet, and the rest is burned up once it enters the atmosphere.

“Unrestricted” earnings

According to the aerospace corporation, the crash was assessed on a long corridor from California through South America and South Africa to Japan.

Most of the time, the “return to atmosphere” is “controlled”, that is, the directions and trajectories are calculated, so that the device often crashes at sea. In 2001, for example, the Mir orbital station “returned” in a controlled manner after 15 years in space. 135 tonnes ended up in the Pacific Ocean, near the Fiji Islands.

As for the status of this Long March 5B (LM5B) rocket, it remained a mystery. For the last rockets to be sent into space, the large phases quickly break up in the sea after launch. This is an international standard, which is not respected by China. SpaceX has since developed reusable stages. But LM5B reaches orbit and then circles the Earth until the atmosphere’s gravity kicks in.

Impossible calculations

And why was it so hard to find? Because the machine orbited the earth at a speed of 27,400 km/h. Everything is going to change depending on the exact moment he starts to descend. A difference of one hour in atmospheric entry represents a difference of 27,350 km.

In addition, the machine did not move in a “straight” way, it turned in all directions. And the density of the upper layer of the atmosphere varies. Jonathan McDowell of the Aerospace Corporation said, “It is impossible to predict when a satellite will melt down and begin self-destruction.”

Although countries along this corridor trembled, scientists wanted to reassure: “There is a 99.5% chance that nothing will happen,” the aerospace corporation continues. That seems to have been the case.

However, it is necessary to take into account the main engine, but its debris. In May 2020, the stage of an LMB5 crashed into the sea, but its wreckage was seen over much of West Africa. In any case, many were happy to learn that the sky did not fall on their heads this Saturday evening.