As space junk proliferates in LEO, space exploration is at risk. Space companies all around the world are working on projects to remove space junk, explains Dr. Max Polyakov in a WeForum article.
The aerospace industry is developing solutions that will perform proactive trash removal. Yet, multiple collaborative actions are needed to both remove the debris and avoid its further accumulation.
Space is infinite, you know. That’s why it is more difficult to comprehend that space can be polluted. However, it is, especially the low-Earth orbit, which is dense with space junk.
Given that we have plenty of pressing concerns on Earth, why are we spending resources on space exploration? Surprisingly, space tech can assist us in solving terrestrial issues. For instance, several companies are now launching satellite constellations to enable Internet access in the most remote areas.
Although we appreciate the advantages of our orbital workers, we still have to plan ahead to prevent the exponential growth of space waste. Before we can move on with space exploration, it is necessary to stop the space junk accumulation.
Current Space Garbage Issue
In addition to 2,200 operational satellites, over 3,000 defunct ones are now circling the planet. If more people gain interest in space, there is also a rise in concern about inactive satellites, spent rocket elements, and particles that litter LEO. All of these combined will become space debris, aka space junk.
Since Sputnik I was launched in 1957, orbital debris started accumulating. Almost 130 million fragments of waste, which vary in size from 1 mm to 10 cm, are already orbiting the Earth. The approximate debris mass today is 7,000,000 kg. Even despite orbital decay and debris re-entering the atmosphere to burn up, this process is very time-consuming.
Satellites and space junk are mainly located in two areas: low-Earth orbit (LEO) and geostationary orbit.
Hundreds of satellites are located just 30,000 km above Earth’s surface. This space has plenty of operational spacecraft for weather forecasting and telecommunications, but it is also home to defunct spacecraft.
LEO, up to 2,000 km high, has even more space junk — mostly because it is easier to access. Plus, any spacecraft must travel into low-Earth orbit to reach higher orbits or travel to the Moon and other planets. When in LEO, the spacecraft is not safe due to high collision risks with space junk.
What Causes the Space Junk Problem?
There will always be space junk as long as people send spacecraft into orbits. After the rocket is launched, many fragments are left behind. These include fairings, interstage, etc. On top of that, rockets sometimes explode, which is the top reason for space junk accumulation.
Human activity in space also leaves space junk, such as sensors, pliers, tool kits, and even astronauts’ gloves, behind. Besides, natural debris is formed as a result of asteroid and comet collisions, known as micrometeoroids.
Operational satellites with a short lifespan have the potential to become space waste. The top reasons that define the satellite’s lifetime are the amount of fuel to make maneuvers, battery, and solar panel capacity. All of those deteriorate with time and, on top of that, satellites are hit by space debris, which speeds up the deterioration process. If a defunct satellite enters Earth’s atmosphere, it gradually disintegrates. The mechanism takes time, though, especially if the orbit is high.
Since 1960, the amount of trackable fragments of space debris orbiting Earth has increased significantly. Given that existing junk affects currently operational spacecraft, this number will continue to grow. This effect is called “the Kessler syndrome,” named after NASA scientists who first pointed that issue out. The takeaway of Kessler’s hypothesis is that LEO could become unavailable for future spacecraft if the junk continues to accumulate.
Debris of any scale is a hazard; even the smallest paint and dust particles may damage spacecraft optics and panels since collisions happen at high speed and with enormous force. In particular, it takes the same volume of energy to strike a 1 kg object at 7 km/s speed as it does to detonate 6 kg of TNT. This, in turn, creates more defunct spacecraft and more space junk.
In the future, LEO will get much more congested. Today, US companies SpaceX and Amazon, British OneWeb, and Canadian Telesat are thinking of or already deploying satellite constellations. While some believe the total number of satellites will be around 50 thousand, others expect up to 100,000 satellites.
The more satellites we have in LEO, the higher the collision risks. Just recently, NASA had to attach a resupply module to its ISS to position it higher in orbit and avoid a collision.
What Can We Do With Space Junk?
To help minimize the growing orbital debris threat, NASA published its first recommendations in the mid-1990s, and other foreign organizations followed. The Inter-Agency Space Debris Coordination Committee, which includes ten member countries, reached an agreement on space debris management recommendations in 2002. To keep space as neat and tidy as possible, aerospace companies should follow these instructions to minimize any future damage.
Luckily, space startups are now developing small satellites for orbital junk cleanup. They are introducing advanced propulsion systems, such as plasma, ion, and Hall Effect thrusters. The technology should reduce chemical rocket impact. Besides, the same tech can be used to deorbit defunct spacecraft or satellites that have completed their missions. Ion and plasma thrusters will return these spacecraft into the Earth’s atmosphere, where they will burn up.
Next, researchers in Japan are trying out wooden spacecraft, hoping to keep debris that’s created when spacecraft are deorbited out of Earth’s upper atmosphere.
However, what about current debris and junk that will be created after thousands of new satellites enter orbit?
The development of devices to trap orbital debris is gaining ground. This tech includes magnets, nets, even harpoons. A team of Japanese researchers is working on an innovative de-orbiting solution when a satellite fires a particle beam at the junk, causing it to pause, lower its orbit, and begin its descent to Earth.
It’s only possible to reach a reasonable solution if all space countries cooperate. To date, more than 30 countries launch satellites on their own vehicles, and nearly a dozen use other countries’ rockets. A satellite-sharing program will require each nation to charge the same fee per unit of collision danger for each satellite they place in orbit. However, the countries could charge these fees differently. Similar methods, used both in carbon taxation and fisheries protection, have already been adopted by some countries.
We need coordinated actions from various industries to stop the accumulation of potential space debris. This should also help prevent space junk build-up in the future. So, it is no longer just about cleaning up; it is about sustainable space use.
Dr. Max Polyakov concludes that while space junk in orbit poses risks, its removal presents a tremendous potential for space companies guided by the sustainable use of space resources.