Imagine a snow globe in your hands after you’ve shaken it. That’s a good way to picture the debris field around Earth, where millions of objects both large and miniscule—from dead satellites to paint and exhaust particles—swirl in geosynchronous and low Earth orbit. That said, it’s not quite bumper-to-bumper traffic up there—not yet anyway. But it could get worse, to the point where it begins to seriously hamper space exploration.
As Leonard David in Scientific American writes, space junk removal is not going smoothly: “For more than a half-century, humans have been hurling objects into low-Earth orbit in ever growing numbers. And with few meaningful limitations on further launches into that increasingly congested realm, the prevailing attitude has been persistently permissive: in orbit, it seems, there is always room for one more.”
Perhaps we need to think about sustainability—in cislunar space between Earth and the moon—just as we’re doing on Earth itself as we confront the uncertainties of climate change, and as we continue to launch satellites to do the important work of gathering climate science data.
Kessler Syndrome
In 1978, NASA scientist Donald Kessler had a thought: space debris itself could lead to more space debris, in a chain of events making operations in low Earth orbit next to impossible, or at least very difficult. Kessler Syndrome holds that the space debris caused by one collision would in turn cause another collision, and another, in a cascading catastrophe.
A line from the abstract of Kessler’s original paper reads: “Satellite collisions would produce orbiting fragments, each of which would increase the probability of further collisions, leading to the growth of a belt of debris around the earth,” not unlike the rings around Jupiter and Saturn.
Case in point: an anti-satellite missile test conducted by China in 2007, which created over 2,000 chunks the size of golf balls or bigger, and around 150,000 particles of debris. That’s what happens when two large objects collide with each other, in opposite directions, at thousands of miles per hour.
More recently, in April 2021, astronauts on the SpaceX Dragon capsule en route to the International Space Station were told to don their spacesuits for the possibility of impact with space debris (although it appears to have been a false alarm). As for the ISS itself, it must adjust its orbit to avoid space debris more often than you’d think.
All of this might come as a surprise—unless you’re Kessler, of course.
Burn, Satellite, Burn
Space is big, even the vacuum of space immediately around Earth. The likelihood of suffering Kessler Syndrome is low—but not zero. If we continue with business as usual, and Kessler Syndrome comes to pass, it will put a major damper on our activities in low Earth orbit and possibly even cislunar space.
We’d prefer not to add to the problem, even as we put our own satellites in orbit for our customers.
And there’s a bit of irony here: Many of our satellites are designed to do Earth observation and environmental science. As we learn more about climate change and how to counteract our manmade impact on Earth, it would be a shame for those very same satellites to clutter up low Earth orbit.
That’s why our satellites are expressly designed to “decommission” themselves and burn up in the atmosphere when their useful life is over.
