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Is it realistic to presume that space debris orbiting around the earth will only ever get worse, or will it effectively remain the same to some degree of consis

by aogl 8y ago

Is it realistic to presume that space debris orbiting around the earth will only ever get worse, or will it effectively remain the same to some degree of consistency? Or is it more of a thing that it only becomes more of a noticeable problem for us as humans when we are affected. Meaning that the only reason we have a problem with it now as opposed to some previous timespan is that we are sending more and more objects/satellites/etc into orbit and they are being damaged/destroyed/affected, so we therefore write about it and try and come up with ways to stop it?

Filligree 8y ago
> Is it realistic to presume that space debris orbiting around the earth will only ever get worse, or will it effectively remain the same to some degree of consistency? Debris in high orbits isn't a big issue; there's too much space. Debris in low orbits falls out of the sky on a timescale of ~decades, thanks to aerobraking. So it should be constant, given a constant inflow of debris... However, that is only true so long as collisions remain rare. Once there's too much debris, Kessler syndrome will cause it to 'breed' and close the orbitals for decades. The above also doesn't account for super-popular high orbits, i.e. geosynchronous. A sufficient amount of debris in that orbit could close off that one for millennia (or until cleaned), but at least there are alternatives.
- bargl 8y ago
  Geosync orbits have a de-orbit requirement (at least US operations do). So they have to keep enough fuel to go into a higher orbit after their lifetime. This wasn't always the case but it is now. Also Geo orbit (while popular) is only useful if you get a fairly large degree of it all to yourself. My current understanding (correct me if I'm wrong) is that most satellites operate at fairly large distances from each other in Geo about 0.5 degrees apart is normal. Mostly because the antennas sending signals from have a wide beam at the point they hit the satellite and affect adjacent satellites. So they have to distance the Adjacent satellites far enough apart so as to be effective in communications. This isn't a problem for different frequencies, so you might stack a K and C band satellite on top of each other. But most of the Geo beasts have full capacity for the spectrum they are legally allowed to use. Also, I'm speaking strictly about COMM satellites. I haven't done any practical application on anything else.
ArtWomb 8y ago
Yes, it's a combination of the fact we are living with increased dependence upon space based systems for weather, navigation, communication, defense, etc. And the enormous cost in production and deployment. Tracking space junk and issuing course corrections to orbiting satellites won't scale. As demand for low earth orbit real estate surely will increase with the coming New Space era of zero-g factories, space tourism and myriad other ventures. Clearing space debris is vital to continued exploration and represents an enormous opportunity, not to mention an engaging engineering challenge ;) The linked bi-directional plasma solution seems really elegant to me. And is feasible even for objects several meters in size. With fewer possible mishaps than say laser ablation. More detail here: The quest To Conquer Earth's Space Junk Problem https://www.nature.com/articles/d41586-018-06170-1 https://www.nature.com/articles/d41586-018-06170-1
panzagl 8y ago
Most of the debris in orbit is a result of 2 events, one of which was a purposeful action of the Chinese government. So if humanity can refrain from blowing up satellites, or at least keep from blowing them up in the stupid way the Chinese did, it should remain manageable. Of course, some of the most difficult to track debris was put up there in the name of science- the Telford needles, pieces of tether, and shreds of solar sails. If the big net experiment from a couple of weeks ago had gone awry, we'd have another difficult to track fabric-like bit of junk shredding itself into smaller yet still dangerous pieces up there.
- A2017U1 8y ago
  Was a bit sceptical at first but this seems fairly correct. There's been numerous collision events, only one stands out as intentional and of greater magnitude than all the rest. I do wonder how future generations will judge such actions given the difficulty of clean up and general world consensus to not militarise space. https://en.wikipedia.org/wiki/List_of_space_debris_producing_events https://en.wikipedia.org/wiki/List_of_space_debris_producing...
InclinedPlane 8y ago
The space debris around Earth is bad due to several reasons. One is a legacy of disinterest for the problem fueled by a greater concern for the fundamental difficulties of space travel. Consider a stereotypical pseudo case study for a space mission in the '60s or '70s or thereabouts. First you have the launch, each stage is festooned with pyrotechnic actuators, cords, blankets, yo-yo despin bits and bobs, and so forth. Every launch deposits a shower of debris into orbit, which orbit depending on the orbit of the payload, some of them potentially long lived. Bolt heads, wires, paint flecks, etc. The final stage boosts the payload into its orbit then separates. Of necessity the final stage tends to be in a very similar orbit to the final payload, except weighing much more. For example, most sightings of the Sputnik spacecraft were actually sightings of the much brighter upper stage tagging along in orbit behind it. Ah but the stage is not necessarily done doing stuff yet, just not stuff it was intentionally designed to do. The stage will often have leftover propellant in it, and it was common to simply abandon the stage in place (on orbit) after its work was done. As a consequences, a lot of upper stages blew up on orbit after delivering payloads, creating yet another shower of debris into Earth orbit. And finally you have the payload itself, which was very commonly simply abandoned in place once it became derelict. Multiply all of that by the low operational lifespan of early satellites coupled with a high replacement cadence and you have a reason why Earth orbit got crudded up with debris in a short window of time. Today we are considerably more sensible about the problems of space debris so our launches are much cleaner. Instead of every launch creating a new mess in orbit every launch generally just inserts 1 or 2 pieces of large, easily trackable components (the payload and the upper stage, if it wasn't deorbited). For LEO launches the upper stage is typically deorbited immediately, for GTO launches the upper stage typically takes a handful of years to orbitally decay and re-enter. For this reason orbital debris has typically been on a flat or decreasing track over time during any given year. However, there are a few notable events in the past which have generated exceptional amounts of debris. One example is Project West Ford, which put thousands of tiny needles into orbit, which should have re-entered promptly except that some of the needles clumped up, leading them to have long-term stable orbits (which will last hundreds of years most likely), polluting some significant chunks of Earth orbit. Then you have the Iridium/Kosmos-2251 collision and the Chinese ASAT test, both of which injected huge quantities of debris into orbit. In general, all of these things can be cleaned up given application of modest resources, and the fact that we are no longer polluting Earth orbit with debris as rapidly as we once were means that we should be able to sustain far higher levels of space activity with far lower risks due to orbital debris than today.

by aogl 8y ago

Filligree 8y ago

> Is it realistic to presume that space debris orbiting around the earth will only ever get worse, or will it effectively remain the same to some degree of consistency? Debris in high orbits isn't a big issue; there's too much space. Debris in low orbits falls out of the sky on a timescale of ~decades, thanks to aerobraking. So it should be constant, given a constant inflow of debris... However, that is only true so long as collisions remain rare. Once there's too much debris, Kessler syndrome will cause it to 'breed' and close the orbitals for decades. The above also doesn't account for super-popular high orbits, i.e. geosynchronous. A sufficient amount of debris in that orbit could close off that one for millennia (or until cleaned), but at least there are alternatives.

bargl 8y ago
Geosync orbits have a de-orbit requirement (at least US operations do). So they have to keep enough fuel to go into a higher orbit after their lifetime. This wasn't always the case but it is now. Also Geo orbit (while popular) is only useful if you get a fairly large degree of it all to yourself. My current understanding (correct me if I'm wrong) is that most satellites operate at fairly large distances from each other in Geo about 0.5 degrees apart is normal. Mostly because the antennas sending signals from have a wide beam at the point they hit the satellite and affect adjacent satellites. So they have to distance the Adjacent satellites far enough apart so as to be effective in communications. This isn't a problem for different frequencies, so you might stack a K and C band satellite on top of each other. But most of the Geo beasts have full capacity for the spectrum they are legally allowed to use. Also, I'm speaking strictly about COMM satellites. I haven't done any practical application on anything else.

ArtWomb 8y ago

Yes, it's a combination of the fact we are living with increased dependence upon space based systems for weather, navigation, communication, defense, etc. And the enormous cost in production and deployment. Tracking space junk and issuing course corrections to orbiting satellites won't scale. As demand for low earth orbit real estate surely will increase with the coming New Space era of zero-g factories, space tourism and myriad other ventures. Clearing space debris is vital to continued exploration and represents an enormous opportunity, not to mention an engaging engineering challenge ;) The linked bi-directional plasma solution seems really elegant to me. And is feasible even for objects several meters in size. With fewer possible mishaps than say laser ablation. More detail here: The quest To Conquer Earth's Space Junk Problem https://www.nature.com/articles/d41586-018-06170-1 https://www.nature.com/articles/d41586-018-06170-1

panzagl 8y ago

Most of the debris in orbit is a result of 2 events, one of which was a purposeful action of the Chinese government. So if humanity can refrain from blowing up satellites, or at least keep from blowing them up in the stupid way the Chinese did, it should remain manageable. Of course, some of the most difficult to track debris was put up there in the name of science- the Telford needles, pieces of tether, and shreds of solar sails. If the big net experiment from a couple of weeks ago had gone awry, we'd have another difficult to track fabric-like bit of junk shredding itself into smaller yet still dangerous pieces up there.

A2017U1 8y ago
Was a bit sceptical at first but this seems fairly correct. There's been numerous collision events, only one stands out as intentional and of greater magnitude than all the rest. I do wonder how future generations will judge such actions given the difficulty of clean up and general world consensus to not militarise space. https://en.wikipedia.org/wiki/List_of_space_debris_producing_events https://en.wikipedia.org/wiki/List_of_space_debris_producing...

InclinedPlane 8y ago

The space debris around Earth is bad due to several reasons. One is a legacy of disinterest for the problem fueled by a greater concern for the fundamental difficulties of space travel. Consider a stereotypical pseudo case study for a space mission in the '60s or '70s or thereabouts. First you have the launch, each stage is festooned with pyrotechnic actuators, cords, blankets, yo-yo despin bits and bobs, and so forth. Every launch deposits a shower of debris into orbit, which orbit depending on the orbit of the payload, some of them potentially long lived. Bolt heads, wires, paint flecks, etc. The final stage boosts the payload into its orbit then separates. Of necessity the final stage tends to be in a very similar orbit to the final payload, except weighing much more. For example, most sightings of the Sputnik spacecraft were actually sightings of the much brighter upper stage tagging along in orbit behind it. Ah but the stage is not necessarily done doing stuff yet, just not stuff it was intentionally designed to do. The stage will often have leftover propellant in it, and it was common to simply abandon the stage in place (on orbit) after its work was done. As a consequences, a lot of upper stages blew up on orbit after delivering payloads, creating yet another shower of debris into Earth orbit. And finally you have the payload itself, which was very commonly simply abandoned in place once it became derelict. Multiply all of that by the low operational lifespan of early satellites coupled with a high replacement cadence and you have a reason why Earth orbit got crudded up with debris in a short window of time. Today we are considerably more sensible about the problems of space debris so our launches are much cleaner. Instead of every launch creating a new mess in orbit every launch generally just inserts 1 or 2 pieces of large, easily trackable components (the payload and the upper stage, if it wasn't deorbited). For LEO launches the upper stage is typically deorbited immediately, for GTO launches the upper stage typically takes a handful of years to orbitally decay and re-enter. For this reason orbital debris has typically been on a flat or decreasing track over time during any given year. However, there are a few notable events in the past which have generated exceptional amounts of debris. One example is Project West Ford, which put thousands of tiny needles into orbit, which should have re-entered promptly except that some of the needles clumped up, leading them to have long-term stable orbits (which will last hundreds of years most likely), polluting some significant chunks of Earth orbit. Then you have the Iridium/Kosmos-2251 collision and the Chinese ASAT test, both of which injected huge quantities of debris into orbit. In general, all of these things can be cleaned up given application of modest resources, and the fact that we are no longer polluting Earth orbit with debris as rapidly as we once were means that we should be able to sustain far higher levels of space activity with far lower risks due to orbital debris than today.