Space debris, also known as space junk, is the accumulation of defunct human-made objects in space – particularly in Earth orbit – including everything from spent rocket stages and defunct satellites to paint flecks and flecks of frozen coolant. It poses a collision hazard to active satellites and spacecraft.
The problem of space debris is a relatively recent one. The first space objects were launched in the late 1950s, and the problem of space junk did not become a serious issue until the late 1990s. The Kessler syndrome, a scenario in which the collision of two objects in orbit creates a cascading series of collisions that produces an ever-increasing amount of debris, has been studied since the 1970s. However, it was not until the late 1990s, when the number of man-made objects in orbit began to increase rapidly, that the Kessler syndrome became a serious concern.
The increase in space debris is the result of both the growth in the number of launches and the fact that objects in orbit do not stay there forever. Most satellites are designed to operate for a specific length of time, after which they are de-orbited, or brought back to Earth. However, a significant number of satellites and other objects are not de-orbited and remain in orbit indefinitely. As the number of objects in orbit increases, the probability of collisions also increases.
There are currently more than 20,000 tracked objects in orbit, and the number is growing every year. The US Strategic Command’s Joint Space Operations Center tracks more than 13,000 of these objects.
The vast majority of space debris is in low Earth orbit (LEO), with more than 95% of all tracked objects orbiting at an altitude of less than 2,000 kilometers (1,200 miles). The International Space Station orbits at an altitude of about 400 kilometers (250 miles).
As the number of objects in orbit increases, the risk of collisions increases. In 2007, the Chinese military conducted an anti-satellite test, destroying a defunct Chinese satellite. The debris from the destruction of the satellite increased the risk of collisions for all other satellites in orbit. In 2009, two communications satellites, Iridium 33 and Kosmos 2251, collided, creating more than 2,000 pieces of debris.
The problem of space debris has been exacerbated by the growth of the commercial space industry. In the past, the launching of satellites and other objects into orbit was the domain of government agencies and large companies. However, the cost of launching objects into orbit has decreased significantly in recent years, making it possible for small companies and even individuals to launch their own satellites.
The growth of the commercial space industry has led to a significant increase in the number of objects in orbit. In 2018, there were more than 2,200 satellites launched, a significant increase from the 700 satellites launched in 2000.
The problem of space debris is a serious one, and the risk of collisions will continue to increase as the number of objects in orbit increases. The only way to reduce the risk of collisions is to remove debris from orbit.
There are several ways to remove debris from orbit. The most common method is to de-orbit the debris, which means to bring it back to Earth where it will burn up in the atmosphere. However, this is not always possible, and some debris is too large to be de-orbited. In such cases, the debris is removed by “active” methods, such as using a laser to break it up, or by using a robotic arm to grab it and remove it from orbit.
The removal of space debris is a difficult and expensive process. It is estimated that it would cost more than $100 billion to remove all of the debris from orbit. However, the cost of not removing debris from orbit is even higher. A collision between two large objects in orbit could produce enough debris to cause a cascading series of collisions that would destroy all of the satellites in orbit, and disrupt communications on Earth.
The problem of space debris is an important one, and it is necessary to find a way to remove debris from orbit. The best way to do this is to prevent debris from being created in the first place. This can be done by minimizing the number of launches, and by ensuring that all satellites and other objects are de-orbited at the end of their operational life.
Article written by Franck Jr. Walter
contact me at: franck [at] ketrium.com