My review of the literature and interviews with seven experts ranging from aerospace engineers to planetary scientists to astrodynamacists show that the scientific community hasn’t yet reached a consensus about whether the Kessler Syndrome has begun, or, if it has not begun, how bad it will be when it starts. There is consensus, however, that the basic concept is sound and that the space community needs to clean up its act.
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[One] thing that all experts I spoke with agreed on: A Kessler Syndrome cascade is something that, whether it has begun or not, would play out over the course of decades if not centuries, rather than fitting into the runtime of a Hollywood drama.
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At around 400 kilometers and into the 500-km realm — home to ISS and the SpaceX Starlink satellites among others — atmospheric drag plays a major role. Dead satellites and debris usually slow and burn up in the atmosphere in just a few years. This natural cleansing process accelerates when the sun becomes more active and solar coronal mass ejections strike Earth and cause the atmosphere to swell.
“In those altitudes, we can probably do a lot and we will be forgiven,” Linares says.
But this atmospheric drag drops off quickly as one goes higher. By the time you get around 600 km, the altitude of the Hubble Space Telescope, “now you’re talking about decades for things to drag down,” Matney says.
“When you get up to 800 or 900 km, we’re now talking about centuries for things to drag down,” he adds. “When we get up to 1,000 km, you’re talking about millennia.”
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“If there are collision events,” Linares says, “those altitudes can very quickly turn into a Kessler type of scenario where they grow very rapidly into millions upon millions [of pieces] of debris.”
However, humanity would not be “locked in” on Earth in such an event, he says, given that crewed spacecraft headed for deep space would cross the problematic altitudes so quickly. But there are still plausible scenarios that are far from ideal. Linares sees a potential future where “humans probably don’t have any incentive to launch satellites, because we’re losing 50% of them” to collisions with debris, he says.
Matney puts it like this: Kessler Syndrome “won’t cause orbital altitudes to be unusable. It’s more like a gradual degradation that’s going to cost everybody more money.”
From the article:
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