A group of experts from the USA, Russia, China, Japan, and Europe compiled a list of the most dangerous space debris fragments in low Earth orbit. In total there are 165 thousand of such objects, 50 of them threatened with disaster. This is what the American magazine Forbes is writing about.
11 individual teams from countries such as the U.S., Russia, China, Japan, as well as from Europe have analyzed thousands of large space debris currently circulating around the Earth and compiled a report that will be presented in October at the International Congress of Astronautics.
The aim of this work was to jointly decide which objects could generate the most space debris in the event of a collision. The scientists have compiled a classification of these objects according to the degree of probability of their collision with other objects, as well as by mass, altitude, and some other indicators.
Each group made its own assessment to determine the most dangerous objects, and then their lists were compiled into a general list of 50 objects.
“This has never happened before. 11 different teams from 13 countries and organizations agreed on which sites are the most dangerous,” said Darren McKnight, lead author of the report from the U.S. firm Centory.
The scientists hope that the alarm they raised about such objects will force governments and the aerospace industry to act by starting work to eliminate space debris. Today it includes 3 thousand exhausted and failed satellites, 15 thousand small fragments that can be traced, and 150 thousand deadly untraceable space debris. This debris poses a serious threat to the satellites both now and in the future.
The first 20 objects on the list include large rocket gas pedals launched into space by the Soviet Union and Russia (in the list they are called CIS – Commonwealth of Independent States) between 1987 and 2007. Each such gas pedal (designation in the list SL-16 R/B) weighs 9 tons and their orbit altitude exceeds 800 km. In case of collision of two such gas pedals, there will be a catastrophe as the amount of generated debris will be huge.
“If two nine-ton objects collide, the amount of debris in low Earth orbit will instantly double. There will be 15 thousand objects being tracked. This will be the most serious event of all possible. And the chances of such a collision every year are not one in a million, but one in a thousand,” McKnight explained.
These rocket engines fly in space together in groups, i.e. they keep the same orbital trajectory relative to each other.
“Such accumulations are formed over decades. The risk exists all year round. And every year the aggregate collision probability increases,” McKnight added.
The list also includes several satellites, the most dangerous of which is considered to have been launched in 2002 by the European Space Agency and currently inactive satellite ENVISAT. It weighs 7 800 kg and its orbit altitude is 765 km. A serious danger is also posed by the Russian Meteor 3M satellite launched in 2001 and the Japanese ADEOS I and ADEOS II satellites launched in 1996 and 2002.
The rest of the list almost entirely consists of Russian rocket boosters and satellites, as well as two Japanese rocket boosters, one Chinese and one French. In total, 43 objects from the list are of Russian origin, and this number includes 35 rocket gas pedals and eight satellites.
The purpose of this report is to show what objects should be eliminated first of all to clear the Earth’s orbit of space debris. In recent years, several proposals on how to do this have been put forward. In particular, there is the project of the Japanese company “Astroscale” and the British project “Debris removal”, which provide for the capture of such objects and their towing to the upper atmosphere.
At the same time, the report notes that 37 objects out of 50 on the list have a mass over 2 tons. First of all, these are large Russian rocket gas pedals left in the near-Earth orbit. To solve this problem, it will be necessary to invent ways to prevent collisions without trying to remove these objects from orbit, as their return to the dense layers of the atmosphere poses a serious danger.
“Timely collision avoidance (say, through the use of gas clouds that change the trajectory of objects), long-term solutions to reduce the risk of debris and nano tows are three different approaches. The idea is as follows: “Timely collision avoidance (say gas clouds changing objects’ trajectories). When you see that objects are dangerously close together, you have to push one of them slightly to avoid a collision,” McKnight said.
The UN has developed non-binding instructions for companies and countries to eliminate their space debris within 25 years. However, nobody follows these instructions. Many want governments to take more decisive action to clear the orbit of space debris. This is the only way to provide future generations with the same access to outer space as we have today.
McKnight and colleagues hope that their report will help people understand the enormous dangers posed by orbital debris and that this problem needs to be urgently addressed. Now, most people remember the movie “Gravity”, which shows Kessler’s syndrome, as they call the chain reaction of space debris collisions. However, this scenario will be possible only in a few centuries.
“In the next 10 years, we will be concerned not about Kessler’s syndrome, but about the fact that capable satellites will not be able to function reliably due to a large number of deadly and untraceable debris. This will affect the global economy, communications, remote sensing, disaster and accident management, as well as financial operations,” McKnight emphasized.