How low-earth orbit turns into a trash heap

2024 Author: Seth Attwood | [email protected]. Last modified: 2023-12-16 15:55

The trash trail of man has long stretched beyond the planet, far into space. While activists and politicians are deciding what to do with household waste on Earth, tons of equipment that has been used up is accumulating in orbits.

Let's figure out what the space dumps are made of, where they are located and whether "heavenly" debris can fall on our heads (spoiler: this has already happened).

What kind of trash is flying in space

The space age began with the launch of the first artificial satellite in 1957. Since then, mankind has launched many rockets and put almost 11,000 satellites into orbit. In recent years, the number of space missions has increased dramatically. Now near-earth space is being explored not only by states - private firms and non-profit organizations have joined in the business. The load on the orbits is growing.

How the number of objects in near-earth space changed

However, satellites, like any other technique, break down and become obsolete. They are replaced by new devices, and the failed devices are forced to live out their lives in orbit in the form of scrap metal. In the near and distant environs of our planet, "dumps" have appeared.

All inoperable technical objects and their fragments are classified as space debris. Most of it is spent rocket stages, old satellites and their fragments. Despite the constant launches of new devices, working satellites in orbits are much less than "waste". According to estimates by the European Space Agency (ESA), there are 128 million tiny debris in the near-earth space, the size of which does not exceed a centimeter, 900 thousand fragments from 1 to 10 cm and 34 thousand - more than 10 cm. For comparison: there are only 3 working satellites, 9 thous.

Most actively mankind uses low earth orbit (200-2000 km above sea level). This part of outer space is the most "densely populated" and at the same time the "dirtiest". At an altitude of 650-1000 km, the first "dump" is located - old vehicles, various-sized debris and military satellites with nuclear installations "live" here. Such heights for the storage of potentially dangerous objects were not chosen by chance: they can be there for about two thousand years. The second official "testing ground" is located at an altitude of about 36 thousand km - all the old satellites are sent there from the geostationary orbit.

However, space debris "flies" not only in places specially designated for it. A collision with debris in near-earth space can happen anywhere, because it is almost impossible to predict the movement of small particles. But it's really possible to dodge large fragments - most of them are being watched by the world space agencies. If in the coming years companies such as SpaceX, OneWeb and Amazon deploy thousands of communication satellites over the Earth, specialists will have to monitor the movement in orbits much more carefully in order to avoid accidents.

Who keeps track of the debris in space

According to ESA, space observation networks regularly track only 28,000 particularly large debris. The US Space Surveillance Network is one of the premier space debris trajectory analysis services. Experts keep a catalog where objects larger than 5-10 centimeters from low Earth orbit and debris starting from 30 centimeters located near the geostationary are brought in.

In the United States, there are other centers that collect and process data not only on "waste", but also on operating devices. Their geolocations are published in the public domain on the Space Track resource, and from Twitter of the 18th Space Control Squadron, you can learn about the destruction of certain vehicles. Based on this information, an online map Stuff in Space was created, which shows in real time the position of satellites (red dots), rocket bodies (blue) and space debris (gray). The map is updated every day and clearly demonstrates the close "relationship" between operating devices and "waste".

The countries of Europe, Russia and China are also observing movement on space "tracks" using telescopes or geostationary radars. Collisions in orbit are rare, thanks to the services that calculate the likelihood of crashes.

Where does space debris come from?

Despite the fact that collisions in space are rare, they seriously affect the growth of "heavenly dumps". One of the most serious space accidents occurred in 2009: the American communications satellite Iridium and the inoperative Russian military apparatus "Kosmos-2251" could not disperse. Their "meeting" gave rise to a large cloud of small debris and more than 1, 5 thousand large fragments, which to this day remain in near-earth space.

Researchers call explosions the main reason for the formation of space debris. Most often they occur due to leakage or heating of fuel, which remains in the tanks of already spent upper stages, the last stages of rockets and satellites. Equipment explodes due to design flaws or the impact of the harsh space environment. For example, in 2018 Russian and American upper stages "Fregat" and "Centaur" crashed in orbit, in 2012 our "Briz-M" was scattered into fragments. In March 2021, an old US meteorological satellite exploded, and a year ago a stage of the Soviet Cyclone-3 rocket, which had been in near-Earth space for 29 years, turned into 75 drifting fragments.

Tests of anti-satellite weapons leave a large trail of debris. In 2007, China destroyed its own Fengyun-1C with a medium-range missile at an altitude of 865 km. Formed about 3, 5 thousand large objects and an uncountable number of fragments up to 5 centimeters. In 2019, India also fired a rocket at its satellite - about 400 debris scattered in orbits ranging from 200 to 1600 km.

ESA specialists analyzed more than 560 cases of device destruction. As they note, there are other reasons for the formation of space debris in orbits. Often, some of its parts are disconnected from the apparatus, it is destroyed due to imperfections in the structure or fails when interacting with the Earth's atmosphere.

Reasons for the destruction of spacecraft

In 2020, specialists from RS Components analyzed which of the space powers littered the space more strongly than others. It turned out that the largest part of the wreckage tracked today belongs to Russia and the CIS countries - 14,403 fragments. In second place is the United States (8734), in third - China (4688).

Why space dumps are dangerous

Modern satellites are equipped with protection from micrometeorites and space debris, but "armor" does not always save. The debris from the explosion continues to move at an initial speed. Since there is no perceptible friction force in space and the usual gravity does not act, they practically do not slow down.

Their speed can reach 8-10 km / s, which is almost seven times faster than a bullet. The blows of the slower fragments can also be fatal. Pieces over 10 cm in size are capable of completely destroying aircraft. Collisions with fragments of more than 1 cm disrupt the operation of the spacecraft or cause explosions of inoperative objects. Millimeter particles in most cases leave cracks and chips on housings.

In 2016, a tiny debris the size of a speck of dust left a 7mm dent on the ISS window glass. Collisions with any fragments of debris are dangerous for the space station, because it moves in orbit at a speed of more than 7.6 km / s. The ISS regularly performs evasive maneuvers and corrects its orbit: anti-meteorite panels are not able to protect the crew in a collision with large debris. Sometimes cosmonauts are forced to evacuate the station and wait out the moment of a dangerous approach to space debris in the Soyuz spacecraft, in order to quickly leave the “sinking ship” if necessary.

Most of the spacecraft maneuvers are done to avoid "encounters" with debris. These actions are costly. Experts spend hours calculating risks and planning a new trajectory. At the moment of the maneuver, fuel is consumed, which you have to take with you "in reserve", and the devices "stand idle" - they do not transmit the data necessary for the researchers.

For those on Earth, space debris does not pose a serious threat. Small devices manage to burn up in the atmosphere, while large spent parts of rockets or satellites, as a rule, are lowered along a given trajectory into the Pacific Ocean or into uninhabited territories in Kazakhstan. Only once did man-made space debris hit a person. In 1997, a wreck of an American Delta II launch vehicle fell on Oklahoma resident Lottie Williams. The girl was disappointed to learn that it was not a piece of a star that fell on her shoulder, but a fragment of a fuel tank.

NASA scientific consultant Donald Kessler made an unpleasant prediction in 1978. Subsequently, the phenomenon described by him was called "Kessler's syndrome." According to the astrophysicist, one day the concentration of "waste" in space will increase so much that the number of accidents will begin to grow uncontrollably. Debris will crash into aircraft, and those will be torn to pieces and "attack" other objects. Piles of scrap metal will render the lower orbits unusable, and a garbage belt will appear around the Earth, reminiscent of the rings of Saturn. Some experts believe that the critical concentration of man-made objects in orbit has already been reached.