It has been decades since humans started carrying forward space missions and explorations. Embarked circa the 1950s, humans have launched thousands of satellites, rockets, and spacecraft into orbit. Just like on Earth, human activities in space, directly or indirectly, bring about pollution to the boundless, three-dimensional expanse. This is when the term “space debris” enters the picture.
According to NASA, there are more than 27,000 pieces of space debris. This amount will surely keep increasing as long as humans and equipment go into space. What are your thoughts?
What is space debris and what causes it, actually?
Space debris, also known as space junk, space waste, or space pollution is human-made objects left in space that are no longer useful. These objects vary in size; from the big ones such as unused satellites, the remains of discarded rocket stages to the small ones including cables, screws, or paint chips. Astronauts’ gloves even contribute to littering space.
As per Britannica, a lot of space debris is in low Earth orbit (LEO), which is around 2,000 kilometers above the Earth’s surface, and some others are in geostationary orbit (GEO), within 35,786 kilometers over the Earth’s equator. The question now is how this garbage got into space.
Source: Statista. Jun 1, 2021
As previously described, as long as humans and instruments are brought into space, orbital debris is beyond doubt. For example, rocket launches account for the most common cause of space pollution. They dumped fuel, rocket bodies, fairings, and other debris in LEO.
“The biggest contributor to the current space debris problem is explosions in orbit, caused by left-over energy – fuel and batteries – onboard spacecraft and rockets,” Holger Krag, ESA’s Head of Space Safety Program explained.
Collisions of objects also produce other space debris. It happens when two satellites collide and shatter into pieces leaving large amounts of debris. And humans, during their spacewalks, can leave stuff like cameras, scissors, screws, gloves, and other astronaut items needed during the spacewalks.
How does space debris affect the environment?
When space debris falls to Earth, the majority of it burns up in the atmosphere and melts. Even if they drop to Earth, they will most likely go unnoticed since the heat from friction when they enter the atmosphere melts the debris into chemicals. Also, uninhabited places on our planet are wider, and the impact of the debris barely hits the inhabited ones.
The real issue is not the impact of space debris on our terrestrial home but rather its influence on the extraterrestrial environment. How can there not be more space debris? Since future missions go on, and telecommunications companies intend to launch mega-constellations of communications satellites, they will add to their predecessors.
While space and satellite missions are admirable aims, it also means more space debris to occupy the orbit. Accordingly, satellite collisions are prone to happen that will cause more space debris. Besides, it can damage the operating satellites since even a tiny piece of space junk circles Earth at a very high speed.
ESA
The more space junk there is, the riskier it is to launch rockets or spacecraft into orbit, despite the trajectory safety. In the next centuries, these crowds potentially lead to the catastrophe described in Kessler Syndrome.
Climate change in our environment may not have a causal link to space debris. But due to climate change, the atmosphere that envelops our planet is tightening, which means the upper layers of the atmosphere shrink. When the debris re-enters the thinned-out atmosphere, there will be less friction which helps push the space junk from orbit. In other words, most of the debris remains in orbit for a longer period.
The efforts of space debris removal
The emphasis is not on halting space or satellite missions which is detrimental to many, including space agencies, companies, and even research & educational institutions related to this field. Rather, it is about how to overcome the rubbish in outer space.
Of course, the agencies and companies involved in the space sector do not remain silent about this. They have made several attempts so far, and one of them is ELSA-d produced by Astroscale, an orbital debris removal company headquartered in Tokyo.
ELSA-d comprises two stacked satellites. The first component is a service vehicle designed to remove junk from orbit in a safe way, and another one is a client satellite that functions as a replica of debris. The ELSA-d capture system uses a capture mechanism to catch whirling items magnetically.
The system consists of small concentric permanent magnets extended and retracted by a mechanism to facilitate connection with the target harbor. Once attached to the harbor, the capture system may be released using an internal system that progressively pulls the target harbor away. In the end, the spacecraft will eject all propellants and battery fluids before entering the atmosphere.
RemoveDEBRIS, a cooperative effort led by the Surrey Space Center and collaborating with Airbus and ArianeGroup, among others, is another attempt at space debris removal. This tiny spacecraft, launched from the International Space Station, transports a harpoon and a massive net produced by consortium members Airbus.
ESA earlier also announced plans to collaborate with ClearSpace, a Swiss start-up, on a space debris removal mission in 2025. The mission, dubbed ClearSpace-1, will feature a novel four-armed robot that will capture ESA’s remain of Vega Launcher in 2013, Vega Secondary Payload Adapter (VESPA).
“ClearSpace-1 will use ESA-developed robotic arm technology to capture the Vespa, then perform a controlled atmospheric reentry,” according to ESA.
