By Stephen Tuttle | Feb. 20, 2021
Now that we've solved all our earthly problems, perhaps we should look skyward. There are issues lurking up there.
This all started in October 1957, when the Soviet Union launched Sputnik 1, which did nothing more than blink and send a simple radio signal. Many alive at the time watched the little orb whizzing across the night sky, a marvel of sorts. The United States joined the party by launching Explorer 1 just four months later. Since then, 11 countries have launched something into space and several more have built satellites carried by those space-capable countries.
Depending on which information you read, there are somewhere between 100,000 and 500,000 human-made objects orbiting around Earth. Most are what we consider “space junk”: obsolete satellites, spent booster rockets and nose cones, human waste (they don't store it in the International Space Station), various failed materials, nuts and bolts, a Tesla vehicle with a dummy in the driver's seat launched by SpaceX, even an astronaut's spare glove lost during a spacewalk.
According to the Union of Concerned Scientists, there are currently about 3,000 operational satellites up there. But we actively track nearly 15,000 objects bigger than four inches in length.
The orbit of these satellites range from 150 miles to 22,500 miles above Earth. Those in what is considered Low Earth Orbit (LEO) — that’s 500 miles or fewer above Earth — typically zip along at about 17,000 miles per hour or faster, a speed required to keep them in orbit while fighting off Earth's gravitational pull. Those much farther out use a geosynchronous orbit; they stay over the same spot on Earth as we rotate.
All of them, near or far, will eventually succumb to gravity and re-enter our atmosphere in a fiery death. Some of those objects, like the International Space Station (ISS) and others, due to a propulsion system of their own, can delay the inevitable with some minor repositioning. But they will all eventually surrender to the laws of gravity, too.
In fact, according to NASA, at least one such re-entry happens every day. Nearly all will burn up without a trace, a momentary flash in the sky. Some of the larger vessels might have parts that will survive and crash to Earth, as happens a handful of times annually. But no person has ever been injured by falling space debris, and no property damage has ever been recorded, so that isn't the threat.
The real risk is our dependence on space-based technology — and what happens if these satellites run into each other. According to NASA, that isn't just possible; it's “inevitable.” And that could be a problem.
Most of those satellites provide us with telecommunications, broadcasting, data transmission, and weather data. In other words, our television viewing, our smartphones, and our online activities are dependent on satellites. (This does not include various satellites launched under the aegis of the military. Most are likely for surveillance and monitoring, but we don't know what our own military has up there, much less what China, Russia, and others have launched.)
They are nearly all on different trajectories in different orbits, at different speeds, and everyone involved tries very hard to prevent collisions, but they do happen. When two objects going about 17,000 mph collide, the resulting debris field, accelerated by the impact and unimpeded by gravity or atmosphere, travels at what scientists call “hypervelocity,” as much as twice their normal orbital speed. Even small pieces of debris traveling that fast could cause catastrophic damage to whatever they impact. That could cause even more debris or, at a minimum, disable whatever is hit.
The neighborhood is getting even more crowded now, thanks to the creation of microsatellites, mostly used for communication, as small as 4-by-12 inches. India released 104 satellites in one launch back in 2017, and SpaceX recently carried and released 60 slightly larger microsatellites.
In 2009, a U.S. Iridium communications satellite and an obsolete Russian military satellite did collide, resulting in a debris field of more than 500 pieces now rocketing around the globe at about 22,000 mph. In 2007, China intentionally destroyed an obsolete communications satellite while illegally testing an anti-satellite weapon. That debris field contains at least 2,500 pieces. (Weapons in space are prohibited by treaty, but we're pretty certain the US, Russia and China all have deployed such technology.)
Collisions in space aren't theoretical but a reality sufficient to require monitoring by both NASA and our Department of Defense. And there isn't much we can do about the uncontrolled space junk and debris fields except move satellites we can move and hope others avoid collisions by luck.
Satellites are out-of-sight, out-of-mind objects on which we rely every day. Look up and cross your fingers because your next social media post, your next online visit, and your next must-watch television show are all dependent on those scientific marvels avoiding each other.