What is space trash, what are the problems and what is the solution?
One of the biggest challenges we face on the road to a sustainable planet is waste management. All over the world, progress is being made in the search for more and more efficient and sustainable ways to deal with the enormous amount of waste we produce every day, but there is one type of waste that is rarely taken into account: space waste.
Space junk, also called space debris, is all man-made objects floating in space without any function or utility. They are discarded parts of space missions, or debris produced by manned missions, such as the International Space Station (ISS), floating in our low Earth orbit, a few hundred kilometers from our planetary surface.
Specifically, these are everything from discontinued satellites (either due to age or technical failure) that have been abandoned in low Earth orbit or abandoned stages of space launches, to microscopic fragments of peeling paint.
Space trash: the problem
Similar to the treatment of any type of waste (terrestrial or space), the big question we must answer is: how do we deal with it? What do we do with the garbage when it starts to accumulate?
The first thing is to understand why it is a problem. As reported by the European Space Agency (ESA), it is estimated that there are more than 170 million pieces of debris smaller than 1 cm in diameter, 670,000 pieces of debris between 1 cm and 10 cm in diameter, and about 29,000 pieces of debris larger than 10 cm in diameter, floating in space. According to NASA, the amount of space debris orbiting the Earth in this year 2022 exceeds 9,000 tons.
Over time (most of the time, years) the debris usually ends up entering our atmosphere and precipitating to Earth. Small debris, in general, is disintegrated by the heat caused by the speed of the fall. So what is the problem?
For one thing, not all debris that enters our atmosphere disintegrates, but many times it ends up either somewhere in our oceans or on land. This is what happened at the beginning of May last year, when one of the stages of a successful launch by the Chinese Space Agency was trapped in the atmosphere and, for several days, it was not known where it would fall. Measuring 30 meters long by 5 meters wide and weighing about 22 tons, the stage in question was traveling at about 25,200 km/h (25,200 mph). Calculating its exact landing point was practically impossible, the possibilities being as distant as Chile and New York. Finally, and fortunately, the landing point was in the Indian Ocean, near the Maldives.
On the other hand, the greatest danger posed by space debris is related to active satellites (currently about 3,000) and manned missions, such as the ISS, as this debris travels at a speed of approximately 25,300 K/h.
Thus, the impact of a residual object in space can seriously affect, or destroy, an active satellite and, more importantly, can seriously endanger manned missions. From 1999 to early 2021, the ISS has made 29 trips to avoid imminent space debris impacts, 3 of these in 2020.
Although on the scale of the problems facing our planet space debris is far from being a priority (more because of the pressing other problems than the harmlessness of this one), space debris continues to accumulate year after year and there is nothing to indicate that the problem itself will not increase in severity over time, especially as the fledgling space tourism industry develops.
Space trash: the solution
The solution has two parts: the first is to reduce space waste as much as possible; the second is to eliminate the waste that already exists.
Both parts propose extraordinary technological challenges for mankind. Space missions usually involve a very high percentage of waste, not only because of the resources that are consumed, but also because of the parts that are discarded in the process of putting satellites and missions into orbit.
On the other hand, there is still no solution for the disposal of space debris. Currently, there are a large number of laser telemetry stations scattered around the world that serve to control the location and trajectory of space debris (one of the last ones built by ESA on the island of Tenerife, Spain), so that the danger of collision is very low, but that does not mean that the debris is still there, accumulating.
Among the projects that the world's major space agencies shuffle, some ideas that are technologically achievable within an acceptable time range stand out, such as the ClearSpace-1 mission proposed by ESA, which will consist of a system for capturing debris in the lower atmosphere, and which, according to the agency, will begin operating in 2025.
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