Main floor of a Chinese rocket will fall on earth uncontrolled

The rocket could enter the atmosphere between Saturday evening and Sunday, in the early hours, in an area comprising an immense part of America and Australia, all Africa, South Asia and from Europe. But not France.

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A long march rocket (LM-5B) sent the second element of the Chinese space station in the space on Sunday, July 24. In the sentence you just read, the important information seems to be contained in the second part where we understand that Beijing successfully continues the construction of its orbital station. However, the first part of this sentence also contains important information because each takeoff of an LM-5B is accompanied, in the days that follow, with a disturbing question for a large part of humans: “And if the rocket fell on my head? “.

This is again the case with the launcher who left on July 24 who, according to estimates, could fall back on earth between the evening of Saturday July 30 and the early hours of Sunday 31. That said, a margin of error Quite large, of about fifteen hours, remains because it is difficult to precisely model the behavior of the main floor of this rocket, a cylinder 33 meters in length weighing more than 20 tonnes.

Three things are certain: this floor will fall back; Some of its elements, which will not be fully consumed during the start of the school year, will reach the ground; This will happen between the 41 north parallel (the latitude of Madrid or Naples in Europe) and the 41 ^e south parallel which passes south of Africa. No risk for metropolitan France therefore, but this very large zone, which contains the south of Europe, an immense part of America, the whole African continent, the south of Asia and the quasi-integrality of the Australia, all the same brings together 88 % of the world’s population …

a rocket on one floor

Why does this problem not arise with each rocket launch but only with the long step-5b? Usually, the orbit of a satellite is carried out using a two -story rocket (with, possibly, the supplement of powder propellants). The first floor provides for a few minutes most of the thrust effort but it is quickly detached and falls back into any ocean. The second floor, much smaller, then takes over to ensure the orbit of the satellite and is then disoriented.

More powerful Chinese launcher, since he is able to put 25 tonnes in low orbit, the long step in its 5B version does not follow this scenario simply because it has only one floor and not two ( Unlike version 5 short). To fulfill its mission, this main floor therefore rises more than 250 kilometers above sea level and is therefore found satellized for a few days.

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