Greenhouse gases weakening LEO's satellite carrying capacity

Greenhouse gas emissions are altering the near-Earth space environment, which will gradually lower the number of satellites that can sustainably operate there, a new study finds.

The study, conducted by researchers from the Massachusetts Institute of Technology and the University of Birmingham, indicates that rising greenhouse gases such as carbon dioxide in the atmosphere result in more heat being released into space in the form of infrared radiation. This causes the upper atmosphere to cool and shrink.

The shrink decreases the atmospheric density in the low Earth orbit region, reducing the atmospheric drag – a force that pulls old satellites and other debris down to altitudes where they will encounter air molecules and burn up.

With reduced drag, space debris will linger in orbit for decades, occupying valuable space regions and increasing collision risks.

"The sky is quite literally falling – just at a rate that's on the scale of decades," said the lead author, William Parker, a graduate student in AeroAstro. "And we can see this by how the drag on our satellites is changing."

Researchers simulated how carbon emissions could impact the upper atmosphere and orbital dynamics. The simulations forecast that under the effects of greenhouse gases, the satellite carrying capacity of low Earth orbit may drop by 50-66 percent by the year 2100.

"More satellites have been launched in the last five years than in the preceding 60 years combined," Parker said. "At the same time, there's been a massive increase in the number of satellites launched, especially for delivering broadband internet from space. If we don't manage this activity carefully and work to reduce our emissions, space could become too crowded, leading to more collisions and debris."

(With input from Xinhua; cover via VCG)