13-03-2025
Climate Change Is Shrinking Space for Satellites to Orbit
Greenhouse gas emissions aren't just warming our planet, they're reshaping space, too. A new study from MIT aerospace engineers reveals that rising carbon dioxide levels are shrinking Earth's upper atmosphere, leading to long-term consequences for satellites and space debris.
The study, published in Nature Sustainability, focuses on the thermosphere, a high-altitude atmospheric layer where most satellites and the International Space Station orbit. As greenhouse gases radiate heat away from the upper atmosphere, the thermosphere cools and contracts. This reduces atmospheric drag, which is the force that naturally pulls old satellites and debris down to burn up. With less drag, space junk lingers for decades, increasing the risk of collisions.
'The sky is quite literally falling — just at a rate that's on the scale of decades,' says lead author William Parker, a graduate student in AeroAstro. Adding, 'and we can see this by how the drag on our satellites is changing.'
MIT researchers simulated how carbon emissions will impact the 'satellite carrying capacity' of low Earth orbit. Their models predict that by 2100, this capacity could shrink by 50-66%. This means fewer satellites will be able to safely operate, creating a growing congestion problem.
The thermosphere naturally expands and contracts every 11 years with the sun's activity cycle, but greenhouse gases are disrupting this balance. The excessive amounts of gases that are being released is causing the thermosphere to shrink, which in turn will limit the amount of satellites and debris that can safely orbit.
'Our behavior with greenhouse gases here on Earth over the past 100 years is having an effect on how we operate satellites over the next 100 years,' said Richard Linares, an MIT aerospace professor.
The problem is compounded by the surge in satellite launches, particularly from megaconstellations like SpaceX's Starlink, which comprises thousands of small internet satellites. With more than 10,000 satellites already in orbit, operators must constantly adjust trajectories to avoid collisions.
'More satellites have been launched in the last five years than in the preceding 60 years combined,' Parker says. 'One of key things we're trying to understand is whether the path we're on today is sustainable.'
If space traffic continues to stay congested, then some regions of space could become too hazardous to navigate, leading to what scientists call a 'runaway instability' or a cascade of collisions that would create so much debris that satellites could no longer safely operate there.
'We rely on the atmosphere to clean up our space junk,' noted Parker. 'But as the atmosphere changes, the debris environment changes, too.'
If emissions continue unchecked, space, a vital resource for communication, navigation, and weather forecasting, could become dangerously overcrowded.
Jennifer Gray is a weather and climate writer for She has been covering some of the world's biggest weather and climate stories for the last two decades.
