Humans launched a record number of objects into space last year, from satellites to probes to crewed spacecraft. As launches increase, scientists see new risks in the growing number of satellites amassing over the planet.
Some 4,510 objects were launched in 2025, far surpassing the 2,903 objects launched in 2023, the previous high, according to U.N. data. Since the dawn of the Space Age, roughly 25,000 objects have been sent into space.
The U.S. accounts for the bulk of the objects now being launched into orbit, most of which are small commercial satellites. U.S. aerospace firm SpaceX operates a “constellation” of more than 9,000 Starlink satellites, which supply high-speed internet access to users below. The Starlink constellation accounts for most of the active satellites now circling the Earth.
Orbiting satellites are already leaving streaks on photos taken by terrestrial telescopes, and soon they could obscure imagery from the Hubble Space Telescope and other orbiting observatories, a recent study found. Scientists say that the swarms of satellites overhead will impede research and may obscure views of asteroids headed for Earth.
Researchers are also increasingly concerned about emissions from rocket launches and from payloads burning up as they fall back to Earth. “Both of these processes are producing pollutants that are being injected into just about every layer of the atmosphere,” Eloise Marais, an atmospheric scientist at University College London, recently told Yale Environment 360.
There are now roughly 12,000 active satellites overhead, up from just 1,200 a decade ago, according to data gathered by Harvard astronomer Jonathan MacDowell. By 2040, he told e360, there may be more than 100,000 active satellites orbiting the planet.
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