Since We're Filling Our Planet With Garbage, Let's Not Forget Near-Earth Space And The Kessler Effect [View all]

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There’s now a huge amount of junk, or space debris, in orbit. Almost 37,000 objects more than 10cm in size are being tracked by space surveillance networks, according to the European Space Agency (Esa) figures for September. “That stuff’s dangerous, don’t get me wrong,” says John Janka, global government affairs and regulatory chief officer at the communications company Viasat, who is based in Washington DC. “But there’s also – according to Esa, more than 1m pieces of debris between 1cm and 10cm that are lethal and non-trackable. What does that mean? It means you can’t see it, you can’t avoid it, and today you can’t shield your satellite against it.”

But the concern over debris is about more than it damaging an individual satellite or craft. Space operators are acutely aware of a danger known as the Kessler effect or syndrome, named after the Nasa scientist Donald J Kessler, who in 1978 along with Burton G Cour-Palais, published a theory that as the number of satellites increased, so would the probability of collisions. As collisions increase, the more debris is produced, and the greater the risk of more collisions. At a critical mass, one collision could trigger an unstoppable cascade of collisions, such that an entire orbit could be rendered useless. A 2022 overview paper by Viasat paints an almost apocalyptic picture: “If a tipping point is reached, all of humanity would watch helplessly as space junk multiplies uncontrollably. Without timely intervention, we risk bringing the space age to an inglorious end, and trapping humanity on Earth under a layer of its own trash for centuries, or even millennia.”

It continues: “Not only an abrupt end to space exploration, but also the loss of all the benefits of space technology – including navigation, weather forecasting, climate measurements, and even satellite broadband (the intended purpose of the megaconstellations being deployed).” As well as numbers, Janka points out, size is an issue. “We’re putting up tens of thousands of satellites, and we’re putting up increasingly bigger satellites into low Earth orbit – bigger in terms of cross-sectional area and mass – we’re finding that we’re having perhaps some unanticipated impact on things like collision risk.”

He compares it to a bigger sail on a boat catching more wind. “The bigger satellite, the more cross-sectional area, the greater chance of being hit by debris.” And bigger satellites create more debris when they are hit.

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https://www.theguardian.com/science/2024/oct/19/humanity-would-watch-helplessly-as-space-junk-multiplies-uncontrollably-has-the-number-of-satellite-launches-reached-a-tipping-point