Risk in Spain of the Chinese space station falling between March and April

The chances that the reentry of the Tiangong-1 causes personal or material damage, experts reassure, are “one in a billion.”

Rendering of Tiangong-1 as it falls to Earth.

The China National Space Administration (CSNA) had planned for his heavenly palace (Tiangong) a funeral of the highest rank. Exhausted its useful life, the space station, launched on September 30, 2011 from the desert of the Gobi, Mongoliait had to descend in a controlled way until dissolving over the ocean, dropping the pieces that were not consumed during the re-entry far from any inhabited place.

The end of the Tiangong-1the only laboratory in orbit next to the International Space Station (ISS) and her sister, the Tiangong-2, it will be much more traumatic. In March 2016, the Chinese control center lost control. The station has maintained structural integrity but engineers have failed to activate the rockets that counteract the phenomenon of ‘orbital deterioration‘, the drag back to Earth suffered by objects less than 400 kilometers high.

Tiangong, which had to remain between 330 and 390 km of operational altitude, had fallen to 280 when the telescopes of the Natural Park of the Valley of Alcudia and Sierra Madronaoperated byr Elecnor Deimos Castilla-La Mancha from Puertollano, they photographed it as it passed over our sky. The station does not vary its trajectory while descending, and its fall will be precipitated from 250, between March 29 and April 9. Spain is therefore one of the possible impact pointsnotify the European Space Agency (THIS), as well as Portugal, France or Greece.

“We know that the re-entry will be between latitude 43ºN and 43ºS” – he explains. Noelia Sanchez Ortizwho runs the program Deimos Sky Survey (DeSS) by Elecnor Deimos. “There is a possibility that it will fall on Spain, but it is the same as it will fall on any other point in Europe, in the US or in the ocean. And the probability that a fragment will hit us individually is one in a billion. You are more likely to win the Lottery!” – She jokes.

The various “inaccuracies” regarding the Tiangong, such as the 12-day window for re-entry, do not alarm or surprise experts. “The atmosphere slows down the object” – explains Sánchez Ortiz to EL ESPAÑOL. “But it’s too complex an environment, with too many elements, for us to accurately model it. We were wrong by 10% with the predictions: the date of March 29 today has a margin of error of two days. Thus, the ESA will not confirm the final moment of reentry until 24 hours before.

However, the geographical margin will remain open. We are talking about objects moving at a speed of eight kilometers per second” – indicates the aeronautical engineer. Once the moment of re-entry is confirmed, it will be possible to draw “a little path”, in his words: the orbit under which the Tiangong can fall. But the maximum precision will not be reached until about seven hours before the event. And by “precision”, clarifies the Agency, it is understood a margin of error of thousands of kilometers towards which the fragments can be projected.

Upon re-entry, the station will shatter and most of its components will be consumed in the atmosphere. But others are prepared to withstand high temperatures, such as fuel tanks, which will presumably fall to the ground. “As it happened in Murcia” – remembers Sánchez Ortiz in reference to the incident of the ‘black ball falling from the sky’. It was a piece of space debris resulting from an uncontrolled reentry of a satellite, one of those that occur “a couple of times a month” according to the ESA.

“Never, in the 50 years that we have been sending satellites, has damage been caused by these fragments” – warns the director of the program that collaborates with the European system to detect space collisions and satellite fragmentation, as well as in the surveillance of NEOS, Asteroids close to Earth. For objects the size of the Tiangong, 8.5 tons, the international criteria is to recommend a controlled re-entry. But according to the ESA, which monitors space debris along with 12 other space agencies, it has used up all its fuel and does not represent a greater risk than a conventional satellite.

It is still early to know, therefore, if the heavenly palace it will give us a pyrotechnic show over our sky and, in any case, if the storm prospects for the dates considered would allow us to contemplate it. It will be good to bear in mind, points out the European space agency, that we have 10 million times greater chance of being struck by lightning for a fragment of the Tiangong to do.

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