Serra gases do not only put the climate at risk. The more the concentration of CO2 increases in the atmosphere, in fact, the more it is destined to extend the average life of space waste in the low terrestrial orbit. Thus reducing the space available to large constellations of satellites such as Starlink, and explicitly complicating space launches in the next decades. It is the alarm that comes from a study published in Nature Sustainability from three Mit researchers and the University of Birmingham.
The research analyzed the consequences of the greenhouse effect in the highest layers of the atmosphere. Since the 90s, in fact, it is known that greenhouse gases have radically opposed to low and high altitude effects: in the lower parts of the atmosphere they can in fact trap the heat, causing global warming and consequent climate changes; While in the thermosphere, between 100 and 600 (approximately) kilometers in height, the same gases subtract heat by conduction, and radiate it in space, determining the cooling of the atmosphere, which consequently becomes denser.
By thickening these layers of atmosphere, they attract the upper ones so, making the highest shares more rarefied, where the satellites of megacostellazioni or where there are an increasing number of space waste. As a rule, the friction of the atmosphere attracts these waste downwards within a few years, where they end up burning. But if the highest layers of the atmosphere are too rarefied, the return of the objects placed in the low terrestrial orbit begins to take place more and more slowly, the spatial garbage remains in orbit much more than expected, and the space for new satellites becomes less and less.
For this reason, in their new study, researchers have analyzed how the changes expected over the next century will impact the amount of satellites that can be maintained safely in the low terrestrial orbit. Their simulations provide that if the emissions continue to increase, by 2100 the number will be reduced by 50-60 percent of the current one. Once the safety threshold is exceeded, the space crowding will therefore risk producing a series of cascading collisions, which would float the orbit of further debris, making it almost impossible for tens of years the launch of new satellites or space missions.
“We rely on the atmosphere to clean up our debris, and if the atmosphere changes, the ecosystem of these debris also changes accordingly,” concludes William Parker, researcher of the Emit and co -author of the study. “We have shown that the long -term situation depends critically on the ability that we will have in the next decades to reduce greenhouse gas emissions.”