Where Spacecraft Go To Die

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I was trying to think of a thematically appropriate topic for this post with Halloween being right around the corner but still, you know, about space. Then it clicked: talking about the way spacecraft go out means I can also talk about some incredibly unconventional graveyards, and what’s more Halloweeny than that?

So join me as we explore the Spacecraft Cemetery, talk about graveyard orbits, and take a look around at some of the other final fates that our spacecraft have met over the years. That is…if you dare! MWAHAHAHAHAHAHAHAHA!!

(Too much? It was too much, wasn’t it? Whatever, let’s get to the dead spacecraft.)

Death From Above

Our orbital space is pretty full of junk, a lot of which is dead satellites. It’s causing problems, so when a satellite reaches a point where it can no longer function these days we try to do something about it. The easiest thing to do with a dying satellite, at least in low Earth orbit, is to slow it down so it drops into the atmosphere. Many satellites are small enough to simply burn up and that’s the end of it.

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But what about the bigger things? Some satellites are big enough that something is going to survive reentry, and that’s when things can get dangerous. You don’t want big chunks of satellite falling out of the sky and onto someone’s house or car or head. It’s not a good look. For instance, in 1979 NASA’s first space station, Skylab, came down earlier than expected, a potential horror show since parts of it were definitely going to make it through. In the end, the world was fortunate that when pieces Skylab hit the ground they did so in an almost unpopulated area of Western Australia. Nobody was injured, although the town of Esperance hit NASA with a fine for littering. 

One thing the entire world can probably agree on is that nobody wants to be worrying about death from above, whether it’s from a big communications satellite, a science mission, or a space station. And NASA would probably like to avoid future littering fines. That’s why we have the Spacecraft Cemetery.

The World’s Largest Graveyard

The Spacecraft Cemetery is a section of the South Pacific near Point Nemo, the spot on Earth farthest away from any land. The closest islands are over 1,500 miles away. Being so far from any landmasses, ships have little reason to be in the area. It’s about as remote a spot as you can find on our planet. And it’s the final resting place of many of the largest things we’ve ever sent to space. 

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This is where six of the seven Salyut space stations came down between 1971 and 1982 (Salyut 7 made an uncontrolled reentry over Argentina in 1991 when increased solar activity puffed the atmosphere up, increasing the drag on the station and causing it to fall out of the sky unexpectedly. Oops). This is where many a massive satellite has met its end. And it’s where, in March 2001, the space station Mir finally came to rest, the largest thing ever to reenter Earth’s atmosphere. So far anyway.

Because you know what’s a whole heckuva lot bigger than Mir? The International Space Station. It is by far the biggest thing we’ve ever had in orbit, and its days are numbered. Current plans have Russia pulling out of ISS operations in 2028 while the rest of the international partners, including NASA, plan to stay on through 2030. Then it will be time to do something about this orbiting behemoth.

The ISS is low enough that drag from the atmosphere is a slow but persistent issue. It has to have its orbit boosted about once a month, a service provided by the engines of a Progress resupply ship (the station generally has at least one attached to it at any given time). The ISS is not capable of boosting itself. Left on its own, it’s going to come down sooner or later and that’s nearly a million pounds of mass. Large pieces of it will definitely survive. An uncontrolled reentry would be a nightmare, so NASA is already looking ahead to make sure it doesn’t happen anywhere but the Spacecraft Cemetery. 

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It will be an extremely sad day for the world when this crown jewel of outer space engineering meets its end in fire and water in 2031, but hopefully it will be a nice, safe day.

For those wondering about the environmental impacts of repeatedly dumping satellite parts into the South Pacific, it’s a fair question. This is generally considered to be the best of the options on the table, but it’s not perfect. Fortunately the most toxic part of a spacecraft, the fuel, generally doesn’t make it through reentry. It is, after all, highly flammable. What comes down is mostly pieces of the body, hunks of steel or aluminum which, while not great for the environment, at least isn’t poisonous.

Graveyard Orbits

The Spacecraft Cemetery is really only an option for things in low Earth orbit. We have plenty of things in high orbit and geostationary orbit that can’t make it to the atmosphere easily. After all, a geostationary satellite orbits over 22,000 miles away from the Earth (compare that to the ISS’s orbital height of 250 miles). So if they can’t burn up but we don’t want them gumming up our orbital spaces, what can we do with them? 

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Just as some areas of the ocean are more popular for shipping lanes than others, some orbital heights are extremely crowded with operational satellites while others are…not. These empty orbits are considered an acceptable place for defunct spacecraft that can’t get back to Earth to let the atmosphere kill them off. We call them graveyard orbits (they have more clinical names, but that’s definitely the funnest one), and they must be at least 185 miles above any orbits being used by operational satellites.

(And just in case you thought those potential littering fines don’t apply to space, a satellite television company was recently fined $150,000 when they failed to save enough fuel to successfully get one of their dying satellites a full 185 miles above its previous orbit.)

A side effect of graveyard orbits is that these dead satellites are left orbiting far above the Earth. Left on their own, they’ll stay there for millions of years, serving as their own memorials for missions long since concluded. If you want to get very into the Halloween of it all, think of them as their own tombstone and their own ghosts, all wrapped up in a single, forgotten bundle of circuits and solar panels floating in space.

Death Beyond Earth Orbit

While destructive reentry or graveyard orbits are the preferred methods for dealing with spacecraft around Earth, spacecraft in other parts of the solar system can suffer different fates depending on where they are and what they’re doing.

For instance, if your spacecraft is a Mars rover or lander there’s really not much you can do other than just…leave it. The surface of Mars is also a graveyard of sorts, dotted with the still figures of departed craft that made it to the surface and the craters from by others that tried to and failed. The same generally holds true for Mars orbiters—we just shut them down and let physics take its eventual course. For instance, the first thing humans ever put in orbit around Mars was Mariner 9 in 1971. It shut down in 1972, and is estimated to have fallen to the surface sometime in 2022 or early 2023.

In some cases, the death of the spacecraft is used as a method to eke a little extra science out of the mission. For instance, the Rosetta spacecraft explored the comet 67P/Churymov-Gerasimenko, (I call it ChuGer, because 67P/Churymov-Gerasimenko turned out to be a big mouthful when talking about Rosetta during Planetarium shows) which has no atmosphere to burn up in. As the comet moved farther away from the Sun, Rosetta’s solar panels were no longer generating enough power, so it was guided into a descent to the comet’s surface where it ultimately came to rest. It took pictures the whole way down. 

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In other cases, the spacecraft is purposely destroyed to protect the possibility of life in a planet-moon system. This was why Galileo and Cassini were deliberately pushed into the atmospheres of the gas giants they spent years studying, to avoid any contamination of Earthly materials on the potentially life-bearing moons of Europa, Enceladus, and Titan (Cassini also continued transmitting data right up until its antenna burned away in Saturn’s atmosphere. RIP you wonderful, delightful ship).

For the Double Asteroid Redirection Test (DART) mission, the destruction of the spacecraft was the entire point. This thing wasn’t much more than a camera with some engines attached to it so that it could smack into the asteroid Dimorphos and test our ability to change an asteroid’s path through a hard impact. DART dutifully obliterated itself in September 2022, successfully shifting Dimorphos’s path as it did.

Going Gentle Into That Good Night

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Then there are the spacecraft that just…drift away. Several of our outer solar system explorers have gathered enough speed that they’ll never stop, whether they have power or not. Pioneer 10 and 11, Voyager 1 and 2, and New Horizons are all heading outward and are never coming back. Their remains will move farther and farther away from where they came from, just drifting forever through the void of space…in the cold…and the dark…and the silence…forever…

And that’s the creepiest note I can think to end on. Happy Halloween y’all!