How dangerous are uncontrolled falls of rocket stages?

In 60 percent of rocket launches in 2020, at least one of their parts ended up in an unstable orbit and uncontrolled falls into the atmosphere occurred. Experts believe that in the coming years they can cause a lot of harm.

Why are the rocket stages returning uncontrollably?

In order to increase the effectiveness of launch vehicles, they are made multi-stage. This leads to the fact that the upper parts of them gain enough energy after launch to be in an unstable orbit and finally enter the atmosphere uncontrollably and fall in an unpredictable place.

Experts have estimated that 60 percent of all launches ended with the launch of the upper stages into an unstable orbit and the subsequent fall at an uncontrolled point in 2020. These objects could easily have failed to burn up in the atmosphere and not fall into the ocean at all, as happens with carriers, all stages of which life cycle are calculated in advance. 

China is most often remembered in this regard. Already in 2022, parts of its rocket were falling near a village in India. There is also a known situation when, after putting the laboratory module “Wentian” into orbit, the stage of its carrier weighing 23 tons fell uncontrollably to Earth.

But in fact, this danger concerns not only Chinese operators. NASA usually requires companies with which it works to ensure the probability of harm to people or property at a level below 1 to 10 thousand. However, quite often startups are exempt from fulfilling this requirement for one reason or another.

Uncontrolled falls can lead to the death of people

Experts have studied the designs of the available carriers and concluded that they do not completely burn up in the atmosphere. On average, 20 to 40 percent of their structures can reach the Earth and cause harm.

And in conditions when satellites are planned to be launched by whole constellations to ensure their stability against hacker attacks, this danger is only growing. Experts estimate that the chance over the next 10 years of uncontrolled falls will lead to death or injury of a person is from 10 to 20 percent.

At the same time, the danger is unevenly distributed across countries. Most often, uncontrolled falls are carried out by the stages of carriers that put the vehicles into geostationary orbits. Therefore, most of them fall near the equator, and residents of high latitudes can feel relatively safe.

At the same time, carriers are launched mainly by those countries that are located in high latitudes. In fact, residents of the equatorial zone pay for their convenience and economy with their safety.

According to phys.org

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