The weirdest stuff orbiting Earth
🏷️ Tào lao
In July of 1969, Neil Amstrong and Buzz Aldrin left the first human footprints on the Moon. They also left two pairs of boots, a handful of tools, and four vomit bags. This lunar litter was far from the last space junk humanity has produced. In 2006, Suni William lost her camera while tussling with a stuck solar array on the ISS. And the following year, a similar job resulted in a loss of a bag filled with $100.000 worth of tools. These accidental satellites typically have short lifespans before falling back to Earth and burning up in our atmosphere. However, other pieces of space junk, like SpaceX’s Tesla Roadster will be stuck in their orbits for the foreseeable future.
In the early days of space travel, this kind of littering was largely considered inconsequential. But in today’s crowded skies, orbital debris poses a serious threat to the thoundsands of satellites that underpin Earth’s vital technologies. Currently, there are over 131 million pieces of debris whipping around the planet at an average speed of 10km/s. This debris ranges in size from pieces as large as an entire bus to those as small as a grain of sand. But roughly 1 million pieces are at least 1cm across, which is large enough to severely damage most satellites. While losing any spacecraft is bad enough, the knock-on effects are even worse. When satellites crash into debris or each other, such as in 2009, when an American communication satellite collided with a defunct Russian satellite, they can explode into thousands of pieces. And if events like these happen often enough, the increase in debris could trigger a catastropic cascade, that researchers have named the Kessler syndrome, a runaway effect which could destroy untold numbers of orbitting spacecraft.
But what does all this mean for people on Earth? Well, even if space shrapnel does take down a satellite, most debric burns up during re-entry. So the probability of waking up to a spacecraft in your yard is very small. That’s said, some large specimens can survive the trip, such as SpaceX Capsule that landed in an Autralian field in August of 2002. And the odds of something similar happening again, grows alongside the amount of space junk. So, how can we save our satellites and ourselves from all this trash? Part of the solution is to stop creating waste in space, but debris is generated in a lot of ways.
In addition to collisions, solar radiation erodes spacecraft surfaces, motors spew slag, and satellite launches routinely abandon rocket bodies, covers, cowlings and explosive bolts . Since 1957, we’re ferried almost 16000 satellites to space using thousands of disposable rockets. Researchers are finally experimenting with new systems that can send upto over 100 satellites in a single rocket launch. Meanwhile, both NASA and private companies are working to prevent existing satellites from becoming junk by using servicer satellites to refuel, inspect and repair them. But we also need to clean up the junk that’s already up in orbit. When a satellite is ready to retire, engineers can use controled re-entry to intentionally burn it up in Earth’s atmosphere.
Ideally, this would happen as soon as satellite is out of use, but outside the US, current guidelines allow defunct satellites to remain in the orbit for up to 25 years, but this rule has barely been enforced. Beyond retired spacecraft, researchers have identified some particularly dangerous debris, so efforts could be made to tackle them first. Some debris experts have proposed using lasers, based both on Earth and in space, to nudge small debris to a higher, safer orbit or into the atmosphere. And private companies are attempting to use space tug boats to ferry large debris to less dangerous orbits. Whatever the solution, all these satellites and orbital debris reflect human consumption back on Earth. So, if we want to keep using and exploring this final frontier, we need to get better at cleaning up our trash both up there and down here.