One big issue that many people told me about: The problem of space junk in low-earth orbit. Low-earth orbit is a particularly attractive place to operate, because it's not that expensive to reach (compared to further out, certainly), and the price of satellites that can do valuable and lucrative imaging — of the atmosphere, of crops, you name it — is plummeting.
But low-earth orbit isn't really that roomy. This constraint wasn't as evident a problem in the early decades of the exploitation of space, because it was primarily state-based actors who were sending up satellites, and they didn't do it that often. So up until recently, there were only about 2,000 satellites up there.
Now private-sector firms are firing 'em up, and they have plans to send a lot of them. SpaceX has put up another 240 since 2019, and it aims to have about 12,000 circling the planet by 2027, to produce a ring of satellites that can offer high-bandwidth Internet all over the Earth. And that's just one of many companies that have really ambitious plans for the use of satellites.
The upshot is, things are getting more and more crowded up there, to the point where many folks I spoke to (including astrodynamicist Moriba Jah, below) described it as the next looming environmental crapshow …
Indeed, there's already been one collision that produced sprawling orbital pollution. In 2009, a satellite owned by the U.S. firm Iridium slammed into a decommissioned Russian government satellite at more than 26,000 mph. The crash produced 2,300 pieces of debris, spraying off in all directions. And debris is a particularly gnarly problem in space, because when it's traveling at thousands of miles an hour, even a marble-size chunk is like a bullet, capable of rendering a damaged satellite inoperable and unsteerable—the owner can no longer fire its boosters to guide it into a higher or lower orbit. There are currently an estimated 500,000 marble-size chunks up there. Decades of space travel by governments left plenty of refuse, ranging from parts of rocket boosters to stray bits of scientific experiments.
One particularly grim vision of the future that haunts astronomers is the "Kessler syndrome," proposed by the astrophysicist Donald Kessler in 1978. Kessler hypothesized that space clutter could reach a tipping point: One really bad collision could produce so much junk that it would trigger a chain reaction of collisions. This disaster scenario would leave hundreds of satellites eventually destroyed, and create a ring of debris that would make launching any new satellites impossible, forever.
"Near space is finite—it's a finite resource," Jah said. "So now you have this growing trash problem that isn't being remediated…. And if we exceed the capacity of the environment to carry all this traffic safely, then it becomes unusable." That's why a growing chorus of critics are already making the case that space is the next major environmental area to protect, after the oceans and land on Earth. "People seem to really treat resources in space as being infinite," said Erika Nesvold, an astrophysicist who's the cofounder of The JustSpace Alliance. "As we've seen, people don't really intuitively understand exponential growth."[snip]
Part of what makes near-Earth orbit so chaotic is that it is, at the moment, remarkably unregulated—not unlike the internet of the early '90s. An American firm has to get permission from the Federal Communications Commission to launch a satellite, but once it's in orbit, there's no federal agency that can compel it to move out of the path of a collision. Satellite owners generally don't like to move if they can avoid it, because their satellites have a limited amount of fuel; any movement decreases their usable lifespan. On top of that, there are dozens of nations shooting satellites into low-Earth orbit—but no international body coordinating their flight paths. Last fall, the European Space Agency realized one of SpaceX's new Starlink satellites was on a dangerously close path to an ESA satellite. SpaceX said it had no plans to move the satellite; so the ESA decided to fire its thrusters and get clear. This high-stakes negotiation was conducted via email.
That's just a small part of a big story — it also covers the quest for mining water on the moon, the thorny legal question of who can own an asteroid, and what civil rights might look like on Mars. Go read the whole thing!
(That illustration of satellites comes courtesy NASA)