We expect a weekend with our nose up, in search of the Chinese rocket falling uncontrolled towards the Earth. It is the first stage of the Long March 5B carrier, which took off over a week from southern China, managed to bring the Tianhe module into orbit and is now the protagonist of a return that worries the international community. The White House has invoked “responsible space behaviors”, while the head of the Pentagon Lloyd Austinhe said that the US Defense will not try to intercept the rocket, despite having “different capabilities available”. No official communication from China about the situation. Global Times, one of the party newspapers with a global circulation, has adopted a reassuring narrative, explaining that the rocket is now devoid of propellant, and that the aluminum alloy that covers it will burn easily upon re-entry into the atmosphere, reducing much of the mass in fall. Worry, however, the rest of the crowd. THE SITUATION IN ITALY
Also in Italy a special technical table has been activated, with the Italian Space Agency, a member of the Office of the Military Advisor of the Prime Minister, representatives of the Ministry of the Interior, Fire Brigade, Defense (Coi and Air Force), Esteri, ENAC, ENAV, Ispra and the Special Civil Protection Commission of the Conference of the Regions. The table, together with the representatives of the regions potentially involved (it is ten in the center-south, already on alert), will continue to follow all the return operations, providing analyzes and updates on the evolution of operations. WHAT IS FALLING
The carrier successfully departed on April 29 from the base of Wenchang, on the island of Hainan, along the south coast of the country. The cargo on board was particularly valuable: the Tianhe module (“celestial harmony”), the first piece of the ambitious Tiangong-3 (“celestial palace”) program, the third space station of the Dragon. Long March 5B is China’s most powerful rocket. “Designed specifically to launch the modules of the space station into low earth orbit”, explains expert Marcello Spagnulo, “It is almost sixty meters high and weighs 156 tons at take off; and equipped with a powerful first stage to which four side boosters are docked ”. These “fall back into the Pacific Ocean three minutes after take-off, while the huge first stage with its two engines arrives in orbit where it releases the precious cargo”. It is more than 25 meters high by five meters in diameter, with an estimated weight of 18 tons. BECAUSE IT’S FALLING
“Most of the first stages of rockets – continues Spagnulo – do not reach orbital speed and therefore re-enter the atmosphere falling into a predefined re-entry zone which is calculated on the basis of the launch site and the inclination of the target orbit”. Instead, China’s heavy rocket “arrives in orbit, but does not maintain the speed that would place it in equilibrium between the gravitational pull of the Earth and the centrifugal force, and so it falls back; it can take days or weeks, it depends on the growing interaction with the atmosphere that drags it, braking it, on the planet ”. Then there are other elements, “such as atmospheric fluctuations, which are not predictable as they are influenced by solar activity and other exo-atmospheric factors”. These are the variables involved, which still do not allow us to predict when or where it will fall.WHERE IT IS FALLING
There are many ground stations that are following the fall of the Long March 5B. Holger Krag , head of the ESA office dealing with Space Debris within the ESOC center in Darmstadt, Germany, said yesterday that the latest data indicates an elliptical orbit between 165 and 292 kilometers from the surface, gradually decreasing. It therefore remains “difficult” to identify the point of fall. For all, it is an area between the 41st parallel north, and the 41st south, a very wide belt (mostly covered with water) that includes all of Africa, most of the Americas, the entire Indo – Peaceful and almost all of Australia. The 41st parallel north splits Italy in half, which is part of the area for its southern part. WHO IS OBSERVING
The drop point will be clear only a few hours after returning. Meanwhile, forecasts based on observation continue. The latest update of the Aerospace Corporation, linked to the observation made last night, provides for the return on Sunday 9 May, around 5:40 am Italian time, with a margin of error of 16 hours. The Russian agency Roscosmos has been activating its automatic warning system “Aspos Okp” for days, indicating almost the same time range. The 18th “Space Control Squadron” of the United States offers daily reports on the situation. THE TOUGH RUN OF CHINA
It is certainly not the first time that Chinese activities have aroused more than a few apprehensions in the international community. In June last year, on the occasion of the launch of the Beidou satellites (with which China wants an autonomous satellite navigation system competing with the American Gps, the European Galileo and the Russian Glonas), the dangerous fall of parts of the carrier rocket was reported in the areas surrounding the Xichang launch base in southwestern Sichuan province. The images of the impact on the ground showed a thick orange smoke rising on a tree-lined hill, for many an explosion index of nitrogen tetroxide, which is what powers some stages of the Long March 3B, used for launch. It wasn’t the first time, and it wouldn’t be the last. Also for this reason Beijing has pushed hard for a fifth launch base,THE PREVIOUS CASES
However, the case of falls from much higher is different. In May 2020, the Long March 5B will debut for the first time from the Hainan base, with the new spacecraft on board that will carry the taikonauts aboard the third “Heavenly Palace”, the Tiangong-3. After having carried out the mission correctly, the central stage of the vector literally plummeted into the Atlantic Ocean, not without worries, being “the most massive object in recent decades that has re-entered the earth’s atmosphere in an uncontrolled way”. The concern (also in Italy) for the uncontrolled fall of the Tiangong-1 will be remembered at Easter 2018. Episodes that have created some international pressure on Beijing’s space ambitions, believed to be the symptom of a wild ride, without too many frills when it comes to security.
(Foto: The Aerospace Corporation)

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