Imagine I cast a magic spell that caused every Earth satellites orbit to move so they all fell into the atmosphere within a very short space of time. Aside from the loss of services they provide (although feel free to speculate) what effect would these burning objects have on Earth? Would it be comparable to a decent sized meteor or do the low speeds make it a harmless spectacle?
The artificial satellites are pretty small and would pretty much burn up in atmosphere reentry. Now as the Moon is the main Earth Satellite, doomsday for humanity and most of life if it crashed down.
The question for someone more knowledgeable is what damage would the space station do?
As far as reentry is concerned, there’d be just about zero effect on Earth. They’d all burn up in reentry and vaporize. Whatever fragments that made it to Earth would be small. They might still be somewhat toxic, like the hydrazine that needed to be intercepted by a Navy missile in 2008, but really no major overall effect.
I recall Mir being potentially dangerous. I would think the ISS would be some danger based on that. I hope @Stranger_On_A_Train or another expert will show to answer.
I’ve read that the total mass of artificial satellites in earth orbit is estimated to be 9,200 tonnes. So that seems like rather a lot of stuff burning up.
The numbers I see from the Union of Concerned Scientists says 3,350 tons, but that’s active satellites. ~9,000 tons is probably reasonable if you include dead satellites, defunct upper stages, etc.
However, somewhere between 37,000 and 78,000 tons of meteorites burn up in the atmosphere each year. An extra 9,000 tons doesn’t sound like a big increment, even if it is all at once.
Okay so it looks like my fiendish plans have been foiled again. Bah!
Don’t feel bad. If it weren’t for those meddling kids…
Yes, but it’s all burning up individually and separately. When divided up into hundreds of individual satellites, each is burning up in a much cleaner and complete way than a single 9,200-ton mass.
I recall reading from a book that during the Apollo capsule reentries, the amount of energy during reentry was “enough to completely melt and vaporize the command module and its contents several times over.” However, the Apollos were also reentering at a considerably higher speed than most Earth-circling satellites.
Let’s run with 9,000 tons. That’s 18 million lbs. They orbit in all sorts of inclinations, with more near or exactly equatorial than high-inclination or polar. If we assume they’re all orbiting at 30 degrees inclination as a crude average then they’ll all fall in a swath of Earth ~23,000 miles in length and ~4,000 miles in width.
So very very roughly 100 million square miles. In other words very roughly 1 lb of debris per 6 square miles of land, ocean, or overlying atmosphere.
If we assume it’s all aluminum, 1 lb is about 10 cubic inches. So that’s 10 cubic inches per 6 square miles, or 1.5 cubic inches of aluminum reentering per square mile.
I’m gonna bet that except for a fun light show for a few seconds this is a total non-event. Both as to “wreckage” deposited on the surface and as to energy deposited into the atmosphere.
The Earth is very, very big. And (CO2 excepted) the cumulative works of Humankind are very, very small.
If the cleaner accidentally turned off the powerpoint that keeps all of the satellites in orbit (despite the post-it note clearly telling them not to) would they essentially fall straight down, subject to earth rotation? I am particularly concerned about the CIA satellite that is positioned in geostationary orbit directly above my house. Will it fall and crush my clothesline?
Kids these days!
NASA’s Skylab crashes onto Western Australia July 1979
It wasn’t back then. Even cost NASA $400 for littering.
All true about Skylab. I happened to be on a camping trip in the US desert southwest when it reentered and had high hopes of seeing something out in there in the extreme dark. Missed it by nearly the max possible = 45 minutes. The actual reentry area was very roughly antipodal to me.
But … other than ISS, Skylab would be the single biggest / heaviest orbiting object today were it still up there. After that behemoth, stuff gets a lot smaller real quick.
Might even be a bit of space engineering cause and effect in play there as well!
Skylab Stage 3 Black Arrow engine after re-entry
In Spin by Robert Charles Wilson, aliens enclose Earth in a bubble of extremely accelerated time. One of the first things people notice is all of the satellites suddenly burning up on re-entry.
That’s an oxygen tank, not a “stage 3 Black Arrow engine”. Black Arrow is a (defunct) British launch vehicle, totally unrelated to Skylab (which used a modified Saturn V to launch).
If this happens the internet is gonna get real slow.
You mean, if the cleaner suddenly unplugged the machine that keeps them moving? Yes, if a satellite stopped orbiting - if it lost all its’ velocity tangental to the Earth’s surface - it would fall straight down.
Geostationary satellites are not special - they would fall straight towards the center of the Earth, too, but since the Earth is turning, that would make it appear that they had ~1,000 mph tangental velocity.
With Skylab, it wasn’t the entire thing that landed, but rather a small dense substructure that did. I forget what it was, some kind of vault. The rest burned up while descending.
Which is going to be the case for other satellites. If they have something largish and dense, that will survive reentry and hit the ground. The ISS almost certainly has such dense parts but other satellites probably do too. For instance, the Hubble Space Telescope has several instruments which probably qualify. Not its mirror, though. That was made really thin (for a large telescope, that is) and that’ll break up. Perhaps some shards and small chunks will make it down. Other satellites, such as some spy satellites, may also have parts that will make it all the way down.
Yep, got my captions crossed up. Smeg. Much obliged for the correction.