Space junk threat to future space exploration & ways to address the issue
International space organizations are developing recommendations to reduce space debris, while aerospace companies are building spacecraft that can proactively prevent and pick up space junk. Several industries will have to apply serious joint effort to remove current debris and avoid its further accumulation.
There are already over 2,200 operating satellites circling the Earth. At the same time, inoperative spacecraft, spent rockets, and other parts that litter the area – commonly known as debris or junk – are becoming an increasing source of concern.
As mankind first reached space and launched its first artificial satellite, orbital debris started to pile up. By 2020, nearly 34,000 fragments of junk 10 cm in diameter or greater, 900,000 objects ranging from 1 cm to 10 cm, and more than 128,000,000 parts under 1 cm orbit Earth together with operating satellites. The space junk in Earth’s orbit weighs almost 7 million kg. Some of it will re-enter the atmosphere and burn down on the descent all on its own. However, this is a very time-consuming process that takes even more time if the orbit is high.
Where is the junk concentrated right now?
Hundreds of spacecraft are placed in geostationary orbit (GEO) around 30,000 km above the Earth’s surface, in the equatorial plane. The majority are communications and weather satellites, but they share their orbit with other satellites that are no longer functional.
Still, the amount of space junk in GEO is nothing compared to what we have in low-Earth orbit, 2,000 kilometers above our planet’s surface. All spacecraft must fly across low-Earth orbit to reach higher orbits, the Moon, or other planets. The problem is that space junk in LEO is already in abundance, while LEO orbital velocities are the highest. As a result, space junk endangers not just LEO-positioned satellites but every other spacecraft that needs to travel through the orbit.
Space junk origin & removing solutions
Some of the space junk we already have is natural, i.e., comet and meteoroid fragments. However, most of it is man-made, and this debris will exist and accumulate for as long as people send spacecraft to orbits.
As Max Polyakov points out, rocket explosions are the primary reason for space junk accumulation. Failed boosters, firing stages, and other components simply remain in LEO, adding up to natural debris. Operational satellites may also become space debris due to their short lifetimes.
Right now, companies are developing innovative satellites with advanced thruster systems to combat the space debris issue. Most of this tech is aimed at reducing emissions from chemical rocket launches. For instance, Japanese researchers are working on technology that would help reduce emissions from space tugs and other vehicles used to de-orbit space debris back to the Earth’s atmosphere.
Existing debris aside, what about the debris that would eventually result from launching tens of thousands of new satellites? Here, it is crucial to apply some joint effort to ensure our orbits remain uncluttered, and space organizations worldwide are already introducing guidelines that should help with that.