Space exploration might end before it even begins

CupofJoe

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I wonder how much Project West Ford has helped with this?
How do you count things that are so small they can't be tracked?
A company not far from where I work was testing a space based harpoon retrieval system this year or last. It was deemed a success from what I saw.
 

RJM Corbet

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We are going to have to develop force-field shield technology? Spacecraft are by nature quite flimsy and thin-skinned.

Now THAT is an area where the fabulously incredible Mr Musk could try to make himself actually a bit useful -- for once, lol?
 
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-K2-

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I'm a little confused about how the 'magnetic' repulsion system for redirecting debris (traveling at such speeds) will work... and is the best idea. First off, isn't magnetism the weak force when compared to gravity (regarding range)? Secondly, there are not that many magnetic materials used in space objects that would show much response (considering para/diamagnetic), and those that are, of such a small size that I find it unlikely that they'll affect the trajectory to any degree, if at all.

I get brainstorming ideas, but sometimes the tinfoil needs to come off your head first.

K2
 

Robert Zwilling

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We are probably using low orbits because they are the cheapest, easiest way to put things in space. Most of it is probably in a doughnut shape with the areas above the poles relatively junk free. Go high orbit and use junk free channels same way boats navigate close to shore. Low orbit must be really easy to do as one solution the video offered was pushing the stuff into higher orbits instead of working above it. Satellites would probably need more fuel to stay at higher orbits owing to more numerous course corrections and maybe more power to transmit the data. And if high orbit satellites can't do the same high quality surveillance of our everyday lives, oh well.
 

-K2-

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We are probably using low orbits because they are the cheapest, easiest way to put things in space. Most of it is probably in a doughnut shape with the areas above the poles relatively junk free. Go high orbit and use junk free channels same way boats navigate close to shore. Low orbit must be really easy to do as one solution the video offered was pushing the stuff into higher orbits instead of working above it. Satellites would probably need more fuel to stay at higher orbits owing to more numerous course corrections and maybe more power to transmit the data. And if high orbit satellites can't do the same high quality surveillance of our everyday lives, oh well.

K2
 

BAYLOR

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Why not clear the debris with tactical nukes ?
 

Venusian Broon

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I'm a little confused about how the 'magnetic' repulsion system for redirecting debris (traveling at such speeds) will work... and is the best idea. First off, isn't magnetism the weak force when compared to gravity (regarding range)? Secondly, there are not that many magnetic materials used in space objects that would show much response (considering para/diamagnetic), and those that are, of such a small size that I find it unlikely that they'll affect the trajectory to any degree, if at all.

I get brainstorming ideas, but sometimes the tinfoil needs to come off your head first.

K2
Sorry not listened to the article - listening to one about eDNA at Loch Ness, poop knives and the skeleton lovers (actual science!) -

however to perhaps give a stab at an answer.

1) Gravity has the disadvantage of only being attractive. Magnetism can repel (not matter what the charge is). Also for Gravity to be strong, until we find some other way, we need loads of mass or stuff. Magnetic and electric fields can be made that are very strong, much more than gravity, considering the mass of any spacecraft/satellite.

2) The material doesn't need to be magnetic to interact with a magnetic field, it just needs to be charged. And I think there is a good chance that most metallic objects in orbit will get charged one way or another. Sunlight, for example, can pop electrons out of a metal via the photoelectric effect. This has to be built into satellite design, I believe, so it's not an issue for them, but for a wrench orbiting by itself, it's not going to be able to do much about that.

Yes, the smaller the object the more a magnetic field will change it's trajectory. given that you still have to shift it and it's mass must come into it, so...given a field strength you generate I guess you'd have an upper limit on what size of object will not be deflected safetly, but...

...my guess would be that you're less worried about big bits - in that they can be tracked and actually given orbits (?) It's the tiny and small bits that you will not be able to track that might hit and cause unexpected damage, that this system could protect you from.

Anyway that's my first guess.
 

Venusian Broon

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Why not clear the debris with tactical nukes ?
I tend to think that if the answer is 'why not use nukes?' (see other questions like 'how do we give Mars an atmosphere', 'how can we stop a hurricane', etc.) then it clearly is the wrong answer :)

Unless your question is 'how can I cause a great deal of destruction?'

Nukes probably are a good answer to that.
 

Dave

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...It's the tiny and small bits that you will not be able to track that might hit and cause unexpected damage...
Given that you haven't watched the video, you have pinpointed the problem exactly. You cannot catch small objects. It would be too difficult even to vapourise them with James Bond lasers because of their size. Yet each time there is a collision between two objects, it results in a lot more smaller objects, each with the same potential to cause disaster as the larger parent that they came from.

I hadn't realised this. I thought that, given time, eventually everything would fall back to Earth and burn up. I also thought we had plans to catch objects and make them safe. However, the reality is that we will have a dense cloud of very small lethal objects, orbiting at great relative velocities, that will be impossible to remove.
 

Venusian Broon

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Given that you haven't watched the video, you have pinpointed the problem exactly. You cannot catch small objects. It would be too difficult even to vapourise them with James Bond lasers because of their size. Yet each time there is a collision between two objects, it results in a lot more smaller objects, each with the same potential to cause disaster as the larger parent that they came from.

I hadn't realised this. I thought that, given time, eventually everything would fall back to Earth and burn up. I also thought we had plans to catch objects and make them safe. However, the reality is that we will have a dense cloud of very small lethal objects, orbiting at great relative velocities, that will be impossible to remove.
It's a big part of the novel Seveneves I think too. The fragmentation of objects in orbit.

I think it depends on a lot of factors - things in LEO will probably tend to hit drag of the upper atmosphere and will eventually get burnt up. But as you say they could collide and the resultant change in momentum/broke up bits could go into all sorts of strange orbits. And things could be in orbit for a long time.

I suppose the trouble with 'catching' these objects is that you are essentially trying to collide with them. How do you design a system that doesn't fragment into smaller parts due to these collisions? Maybe, taking cue from another SF author, Alastiar Reynolds and the protective cone he puts on his lighthuggers, we'll have to put huge satellites of massive disks of thick ice (a couple of km thick? a few kilometres wide?) that just sit in orbit and let everything hit them, hopefully thick enogh to absorb all the small high energy objects? Or (again remembering Seveneves) we could clear orbits by putting large asteriods into place?

I'm sure there's massive problems with those ideas ;) :) Just chewing the fat and throwing out ideas!
 

BAYLOR

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I tend to think that if the answer is 'why not use nukes?' (see other questions like 'how do we give Mars an atmosphere', 'how can we stop a hurricane', etc.) then it clearly is the wrong answer :)

Unless your question is 'how can I cause a great deal of destruction?'

Nukes probably are a good answer to that.
I was not being serious . :p;)

From an economic standpoint perhaps industry could come up with a cost effective way of removing the orbiting debris?
 

-K2-

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@Venusian Broon ; thanks for the explanations, but how much of a field could it really generate regarding range? IOW, past the problem of needing to orient this object (we don't want it bumping debris higher), if say you could generate a field a hundred meters which sounds impressive 'to me,' that's actually a minimal zone considering.
On the same token, it's not as though you're altering an orbit in a controllable fashion, so risk making matters worse (though temporarily). There is also the issue, I suspect, that if this magnetic generator can move an object, wouldn't that object would affect the MG, equal and opposite and all that?
Lastly, considering the velocity of some of these objects, placing it in a debris field of unknown objects, wouldn't there be the potential for this static field generator to become a target itself?

Those questions posed, what would make more sense to me (which doesn't mean it's right) is a magnetic field net. Not to catch or deflect, yet to slow the debris as much as possible. Then, let gravity do its thing.

K2
 
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Vareor

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It’s funny how not too long ago, the notion of sending thrash into space (or more precisely, throw it at the Sun) was popular. The thought behind it was noble, but I guess a good idea is not always a good idea.

Speaking of good ideas, why not let nature take its course? We’d have a shield against alien threats.
 

Venusian Broon

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@Venusian Broon ; thanks for the explanations, but how much of a field could it really generate regarding range? IOW, past the problem of needing to orient this object (we don't want it bumping debris higher), if say you could generate a field a hundred meters which sounds impressive 'to me,' that's actually a minimal zone considering.
On the same token, it's not as though you're altering an orbit in a controllable fashion, so risk making matters worse (though temporarily). There is also the issue, I suspect, that if this magnetic generator can move an object, wouldn't that object would affect the MG, equal and opposite and all that?
Lastly, considering the velocity of some of these objects, placing it in a debris field of unknown objects, wouldn't there be the potential for this static field generator to become a target itself?

Those questions posed, what would make more sense to me (which doesn't mean it's right) is a magnetic field net. Not to catch or deflect, yet to slow the debris as much as possible. Then, let gravity do its thing.

K2
Well, if you are fitting this magnetic device to all satellites and craft then it doesn't really matter where you shift the debris to, I suppose! It will always be deflected (If this fabled device can work.)

Magnetic and electric forces are inverse-square laws, same as gravity, but range will just be a function of how strong the magnetic field can be produced. We can produce some pretty strong fields now, up to ~15 Tesla (although admitedly that's a one metre long magnet weighing a few tons.). The earth's magnetic field is about 60 μTesla for a comparison. However I haven't worked out what might be a sensible zone given these sort of values for whatever size of debris you might want to deflect.

Re: conservation of momentum. Wouldn't the magnetic field generator, or whatever it's attached to, have flight controls so that it could correct any orbit if it is 'bumped'. Just like satellites have had since more or less the start of the space race. (Plus we're talking about tiny objects with respect to the MFG)

Anything in orbit is potentially a target to these small objects. So yes, so would this would be a target, but this is a sort of force-field you attach to something to protect it. I guess.

As for trying to slow down the debris...the magnetic field would apply a force to any charged particles, and therefore change it's trajectory and velocity. Hence hopefully deflect. To try and slow it so that it would actually go into an orbit that would take it into the atmosphere...would probably mean a much higher magnetic field strength, therefore giving a greater force to apply and probably be much harder to do. Remember we're not talking about linear physics here, were in orbit and things are already travelling at about 7.66 km/s if they are at the height of the ISS. That's pretty nippy.

So I think it would nice if we designed it to do that, but my guess is that it would much harder to do.

Oh and this ain't going to protect you against any objects with no charge. So the rock/ice cone protection idea is probably a good idea too.
 

Robert Zwilling

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While it is heavily energy dependent, the Graveyard Orbit above everything is apparently the safest place to operate. It takes about 100 years for something to fall back to Earth that is orbiting around 600 miles up. Plenty of open space, lots of room, mostly big intact pieces, lower space junk density up that high. 500 miles up it starts to take decades to fall down. Stuff below 370 miles only takes a couple of years to return to Earth. That more or less means everything going up is coming down. Lower it is the faster it is coming down. Right where all the mini satellites will be. Guess they will be called disposable satellites so everyone will be on the same page. Cheaper to send up a new one than try to fix/update an older model. The disposable economy is alive and well on its way to outer space. Same way we figured the oceans could take an infinite amount of garbage dumped in them is the same way we are figuring space works. That only lasted 50 years. Space should be capable of handling an infinite amount of garbage for an infinite amount of time. But it can't, only this time, instead of dead sea animals, it will be dead space equipment, shot to death by it's own makings.

Too many articles online to look through to find the scattering pattern of the smaller debris created by the collisions of bigger pieces. I guess, we got several choices. Probably going in all directions, and the ones heading away from Earth, call that space junk evaporation. So space junk could go higher, lower, or stay at the same elevation just going in a different direction. If most of it was getting blown down towards Earth it would at least disappear faster, although operating existing equipment closer to Earth would face more problems.

We got at least 3 things to look forward to. The first is when the mass of the space junk exceeds the mass of the asteroid belt out past Mars. The second is when it starts to get enough pieces to cause enough attraction within the cloud so that visible rings can be seen. A new hobby could be monitoring satellites, waiting for them to get blown away by a tiny pebble tearing through it at 17,000 mph. They could set up odds in Las Vegas for naming the next satellite to be hit. That could be a really random lottery, at least until we can see the really tiny stuff. Maybe that shouldn't be too hard, from the ground up, the atmosphere, etc., that kills the resolution. But if there was a fleet of satellites whose sole function was to map all the space junk all around them, it probably wouldn't be hard to do at all. Then the auto pilot program for cars could be used to keep all the satellites out of harm's way.
 

Venusian Broon

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Thanks @Venusian Broon for taking the time to explain.

K2
To be honest, I am not sure such a system would be practical or plausable, I was just extrapolating from bits and pieces that I know, or can best guess at ;).

But it was fun thinking the various strands through, so thank you for the discussion too!
 

Vertigo

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Low Earth Orbit isn't popular only because it is easier to achieve but also because it's easier to communicate with. Satellites have a fair amount of power available to them with solar arrays but the farther away the satellite is from the Earth the more power is required to transmit to it from Earth's surface. This is fine(ish) for fixed sites with big transmitters. But not so good if, for example, you are trying to set up a mobile phone satellite network because all you nice small mobile phones have to have enough power to transmit not just a kilometre or two to the nearest base station but much farther to a satellite. If that satellite is in LEO you might get away with a suitcase sized satellite phone but if it's much farther out it's going to be a problem.

Geosynchronous orbit is fine for things like TV because our TVs only receive a signal transmitted by the satellite, however to transmit a signal to a satellite in Geosynchronous orbit (such as the original tv signal to be relayed) requires a rather more bulky and expensive bit of kit.

So the lower the orbit the easier to communicate with it.
 
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