As happened in 2020 and 2021, also this year a component of the Chinese Long March rocket is in a phase of uncontrolled fall towards the Earth.
The impact, expected on 30 July with an uncertainty of more or less 15 hours, is of an element of the Chinese Long March 5B rocket, which on 24 July brought the second module of the Chinese space station Tiangong into orbit.
According to the US Center for Orbit Studies and Space Debris Reentry (Cords), the rocket component will likely remain in flight for about a week.
However, it is still early to understand where it will fall: the area affected by the fall of space debris is for now limited to the northern Pacific Ocean, but it is impossible to have reliable data until a few hours before returning.
It is also expected that the rocket component will not burn completely in the atmosphere: "We expect a fragment with a mass of between 5 and 9 tons to reach the ground," note the Cords experts.
The main stages of most orbital-class rockets are designed to descend into the atmosphere shortly after take-off, with a guided drop into the sea or sparsely populated sections of land, or to make landings so they can be reused, such as the Space X Falcon 9
"60-70% of the central stages of rockets launched into space are subject to uncontrolled reentry, but usually they are much smaller objects", explains to ANSA Luciano Anselmo, researcher at the Institute of Science and Technology of the Information "Alessandro Faedo" of Cnr (Isti-Cnr) and expert in spatial dynamics.
"In this case, on the other hand, we are talking about 25 tons - adds Anselmo - it is the most massive object that can return without control".
The part of the rocket that will fall back to Earth, in fact, is the main stage, that is the central cylinder equipped with two engines.
“Normally this large stadium does not enter orbit, but falls back into the sea in a controlled manner immediately after launch,” continues Luciano Anselmo.
“This type of mission, on the other hand, required that the main stage also enter orbit, thus posing the problem we are discussing, because there is no possibility of restarting the engines to guide the fall of the rocket.
And it is a problem that will recur - says the researcher - with the launch of the third module necessary for the construction of the Chinese space station Tiangong ”.
The component of the Long March 5B will fall back to Earth in an uncontrolled way, as had also happened in previous missions: after the first launch took place on May 5, 2020, the main stadium fell off the west coast of Africa, while in May 2021 in the ocean Indian.
"It is clear that China is not meeting accountability standards regarding their space debris," said Bill Nelson, NASA administrator.
"It is essential that China and all nations traveling in space, as well as commercial entities, act responsibly and transparently - adds Nelson - to ensure the long-term security, stability and sustainability of activities in space".