Space Junk Cleanup - Innovation & Responsibility

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kelvinzero

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Ideas for removing space debris

I threw this idea out in a couple of space debris threads but it sort of got buried. People prefer to talk about big lasers and big balls of aerogel :)

The idea is basically this:

Deliberately polute near space with a faint cloud of particles in a retrograde orbit. You dont even necessarily need a special mass budget for this. If the propellent you used for keeping satelites in orbit was of the correct velocity it could also perform this role.

Why is this meant to work?

Such material would only be a minor nuisance to a large object. It would only place high earth orbit objects under the same sort of conditions that LEO objects already have to deal with: A constant friction with a very faint atmosphere that degrades the orbit over time.

It would be far more affective on small objects, because the ratio of surface area to momentum is far greater for small objects. (this is why cannon balls fall faster than feathers, whatever Newton says)

So, simplistically at least, each kilogram of particles you put into a retrograde orbit eventually neutralises a kilogram of dangerous debris even (and especially) if it is distributed in many small particles.

Each particle might orbit for decades before hitting something but that is fine because this is a problem that has to be managed over decades. The aim is to build up an equalibrium so that junk is removed at the same rate it is created so the risk remains constant.
 
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MeteorWayne

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Re: Idea for removing space debris

I see a number of problems. First of all, the particles would have to be the size of smoke particles or smaller. Even a paint fleck almost puncture the shuttle window, and it's unlikely that it was in a retrograde orbit. Since Energy= 1/2 mass times velocity squared. even very small particles could present a danger to orbiting spacecraft.

Second, if it did work and not destroy spacecraft (thereby exacerbating the problem) it would shorten the lifetime of any spacecraft in orbit. That means more replacement craft, which of course means more debris, etc :)
 
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aphh

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Re: Idea for removing space debris

I propose a very large surface area collector plate that the smaller debris would penetrate and hang onto. After the mission is over the collector plate is guided for a re-entry.
 
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MeteorWayne

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Re: Idea for removing space debris

But smaller debris, while a danger to spacecraft, isn't the real problem. It'e the 5 pound chunks like the one that threatened the ISS last week, and they would punch through or destroy an object like yours, thereby creating more debris... etc :)
 
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aphh

Guest
Re: Idea for removing space debris

Big objects would punch through, true, but they would still lose energy thereby shortening their life on orbit. We need to do this at some point, there is no avoiding it.
 
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MeteorWayne

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Re: Idea for removing space debris

But if they punch through, they will be creating more large pieces of debris, which only make the problem worse!!
 
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aphh

Guest
Re: Idea for removing space debris

I realize that.

But to remove space debris from orbit means slowing down the objects, so that their orbit decays faster than it would do otherwise. So we align the collector plate so that no collision or impact adds to the kinetic energy, but only decreases it.

Basically the whole problem boils down to how to make the unwanted objects lose momentum. Shoot them with a laser, make them punch through kevlar or something else.
 
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vattas

Guest
Re: Idea for removing space debris

What about huge magnetic buble - like these, proposed for protecting interplanetary manned spacecraft from radiation?
Not effective against bigger objects, but paint fleck, fuel droplet trajectories should be affected. All such items have some charge...
Just a wild late night idea, not backed by any kind of research... ;)
 
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kelvinzero

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Re: Idea for removing space debris

MeteorWayne":16q4q4be said:
I see a number of problems. First of all, the particles would have to be the size of smoke particles or smaller. Even a paint fleck almost puncture the shuttle window, and it's unlikely that it was in a retrograde orbit. Since Energy= 1/2 mass times velocity squared. even very small particles could present a danger to orbiting spacecraft.

Second, if it did work and not destroy spacecraft (thereby exacerbating the problem) it would shorten the lifetime of any spacecraft in orbit. That means more replacement craft, which of course means more debris, etc :)
When you say a number, do you mean 2? 2 is a number.. :)

To the first part, yes the idea is that the particles are microscopic, perhaps simply the molecules of the propellent used to maintain a satellite's orbit. This implies some sort of ion thruster with an exhaust velocity double your orbital velocity I suppose.

In the second part, yes it would shorten the lifetime of any spacecraft in orbit, or to put it another way the budget for propellent to keep it in orbit would be a bit higher. But there are two crucial points:
(1) The affect on smaller particles will be much greater because surface area is proportional to r^2 and mass is proportional to r^3. All other things being equal, the affect on a 1 ton object would be 1/100th that of a 1gram object.
(2) We may only be talking about forces that remove paintflecks in decades that would otherwise have built up for centuries. It would probably take a thousand times longer to remove a satellite than a paint fleck. That is tens of thousands of years.

Finally, is it such a bad thing if any satellite needs a small functioning VASIMR or similar to stay in orbit? We are not talking about huge amounts of propellent because in the absolute worst case it cancels. Every atom of propellent you launch comes back and hits you and only you. Obviously this wont happen.
 
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MeteorWayne

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Re: Idea for removing space debris

kelvinzero":2jo8egqq said:
MeteorWayne":2jo8egqq said:
I see a number of problems. First of all, the particles would have to be the size of smoke particles or smaller. Even a paint fleck almost puncture the shuttle window, and it's unlikely that it was in a retrograde orbit. Since Energy= 1/2 mass times velocity squared. even very small particles could present a danger to orbiting spacecraft.

Second, if it did work and not destroy spacecraft (thereby exacerbating the problem) it would shorten the lifetime of any spacecraft in orbit. That means more replacement craft, which of course means more debris, etc :)
When you say a number, do you mean 2? 2 is a number.. :)

To the first part, yes the idea is that the particles are microscopic, perhaps simply the molecules of the propellent used to maintain a satellite's orbit. This implies some sort of ion thruster with an exhaust velocity double your orbital velocity I suppose.

In the second part, yes it would shorten the lifetime of any spacecraft in orbit, or to put it another way the budget for propellent to keep it in orbit would be a bit higher. But there are two crucial points:
(1) The affect on smaller particles will be much greater because surface area is proportional to r^2 and mass is proportional to r^3. All other things being equal, the affect on a 1 ton object would be 1/100th that of a 1gram object.
(2) We may only be talking about forces that remove paintflecks in decades that would otherwise have built up for centuries. It would probably take a thousand times longer to remove a satellite than a paint fleck. That is tens of thousands of years.

Finally, is it such a bad thing if any satellite needs a small functioning VASIMR or similar to stay in orbit? We are not talking about huge amounts of propellent because in the absolute worst case it cancels. Every atom of propellent you launch comes back and hits you and only you. Obviously this wont happen.
Well, you raise some good points, but I assert the reality is a bit different.

The deorbit time for objects in LEO is not tens of thousands of years, it is decades or hundreds of years. The OP was not clear as to what height the proposed cloud was to be put in. At 600 km or 800 km, such as the Iridium or Kosmos level most of the orbits are polar, which means that there's not really a "retrograde" orbit. Some go south to north, others go north to south, and they all do both at one time or another.

Secondly, since none of the current satellites in those orbits have any VASMIR type propulsion available. So this plan would doom every specraft in LEO to an early demise, which means more launches (and money to pay for them) which would of course create more debris...rinse and repeat....
 
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kelvinzero

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Re: Idea for removing space debris

MeteorWayne":2yj6rk9z said:
Well, you raise some good points, but I assert the reality is a bit different.

The deorbit time for objects in LEO is not tens of thousands of years, it is decades or hundreds of years. The OP was not clear as to what height the proposed cloud was to be put in. At 600 km or 800 km, such as the Iridium or Kosmos level most of the orbits are polar, which means that there's not really a "retrograde" orbit. Some go south to north, others go north to south, and they all do both at one time or another.

Secondly, since none of the current satellites in those orbits have any VASMIR type propulsion available. So this plan would doom every specraft in LEO to an early demise, which means more launches (and money to pay for them) which would of course create more debris...rinse and repeat....
I hadnt thought properly about those polar orbits. I had assumed a retrograde (wrt to earth) orbit would tend to slow any other orbit but perhaps particles hitting something at right angles in a polar orbit would add speed instead of removing it.. You could have particles going every which way. This would mean it would always slow objects on average just as an atmosphere does. I can think of several variations of orbit but perhaps the simplest is that each satelite simply uses its propellent only to clear out its own orbit. objects outside any of these orbits would tend to cross them randomly, and random crossings would on average slow them.

I hadnt really specified an exact height for this to work at. Just wherever there is the most density of junk accumulating. This would not be in very low earth orbits because the atmosphere would quickly take care of these. This probably is what originally gave me the idea.

About the deorbit time for object in LEO not being tens of thousands of years, that really goes to my point. Assuming the drag on the objects we want to remove is about a hundred times greater we could reduce the orbital life of these particles to years without a great effect on satellite sized objects.

Im not too worried about existing satellites since they would probably all be retired by the time we built up any useful sized effect. This idea is about a sustainable solution for the decades to come.

There is a simple mathematical reason why the drag would not degrade the satelite lifetime to the point where the extra launches negates the benifits: The mechanism for putting this material up there is also what keeps the satelites up. You fire this material out at sufficient velocity that it remains in orbit in the reverse direction. If every single bit came back and hit you then they exactly cancel. Any better and you win. As mentioned earlier you could expect to do better by a hundredfold. So for the cost of one percent more station keeping fuel, you can remove a mass of space junk equal to 99% of your station keeping fuel.

One place where this might fall down is that I am neglecting natural orbital decay. What proportion of these particles would escape or return to earth without hitting anything manmade at all?
 
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astc

Guest
Re: Idea for removing space debris

We are thinking something like this, but ours is for Nuclear waste management.

Our company has been speaking to Nasa for some innovative projects, and this is of interest to many. As time passes more countries would be dependent on Nuclear power, and there would be waste. We have the ability to transport the waste up into space, and we are thinking of having a base, to do storage, and to make countries pay us a fee to transport and store nuclear waste.

Do let me know if anyone here has anything interesting plans. I can easily be reached on my email.

Best
J
 
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tampaDreamer

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Re: Idea for removing space debris

astc":2x65biz0 said:
We are thinking something like this, but ours is for Nuclear waste management.

Our company has been speaking to Nasa for some innovative projects, and this is of interest to many. As time passes more countries would be dependent on Nuclear power, and there would be waste. We have the ability to transport the waste up into space, and we are thinking of having a base, to do storage, and to make countries pay us a fee to transport and store nuclear waste.

Do let me know if anyone here has anything interesting plans. I can easily be reached on my email.

Best
J
Statistically speaking, wouldn't it be safer to store nuclear waste in an urban area at the top of a skyscraper in a glass room with "I hate islam" stickers on it, than to blast it off on a rocket into low earth orbit?
 
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astc

Guest
Re: Idea for removing space debris

lol, I like the idea of I hate Islam thingy!!!

well, I guess too much nuclear waste would be an issue and we are just trying to find a way to store hazourous waste in a safe and protected place.
 
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MeteorWayne

Guest
Re: Idea for removing space debris

Latest info of interest:

http://www.space.com/news/091006-space- ... eanup.html

"Experts focused on the escalating menace of orbiting litter during "Green Space: Addressing Space Debris - End of Life Operations," a recent session at the Space 2009 Conference and Exposition in Pasadena, Calif., staged by the American Institute of Aeronautics and Astronautics"

snip

"Debris removal is part of a whole suite of solutions," said Wade Pulliam, Program Manager for the Defense Advanced Research Projects Agency (DARPA) in Arlington, Virginia. That solution set, he said, includes satellite situational awareness, avoidance maneuvers, as well as removal of end-of-life satellites.

"I think [debris] removal is important and critical in the future...and it's also a technically difficult problem," Pulliam said. There are different solutions for different regimes at different particle sizes, he explained, so grappling with small particles in low Earth orbit in not the same as dealing with large derelict satellites in geosynchronous orbit."

snip

"DARPA has initiated a study to examine the problem, survey possible solutions, and determine if emerging technologies and concepts can be combined to provide an economical solution to this problem," Pulliam told SPACE.com.

To this end, DARPA and NASA are co-hosting an international conference on orbital debris removal in the Washington, D.C. area December 8-10, Pulliam explained.

"This first of its kind conference is solely dedicated to addressing the issues and challenges involved with removing manmade orbital debris from Earth orbit," Pulliam said.

....

See the link at the top to read more
 
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silylene

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Re: Idea for removing space debris

The imperative thing is to prevent a runaway chain-reaction formation of space debris in LEO. It's simply a matter of time before this happens, and then we are screwed. The biggest danger is at the current Iridium orbit level. The best way to prevent this is to de-orbit all of Iridium constellation, now. Iridium has only a marginal economic and technological value, and Ithink this value is outweieghed by the risk of another Iridium collision with debris or another satellite.

We had a nice discussion on this in another forum, before de-pluckification lost a bunch of my threads and posts on this subject.
 
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stevekk

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Re: Idea for removing space debris

silylene":30yzb1vl said:
The imperative thing is to prevent a runaway chain-reaction formation of space debris in LEO. It's simply a matter of time before this happens, and then we are screwed. The biggest danger is at the current Iridium orbit level. The best way to prevent this is to de-orbit all of Iridium constellation, now. Iridium has only a marginal economic and technological value, and Ithink this value is outweieghed by the risk of another Iridium collision with debris or another satellite.

We had a nice discussion on this in another forum, before de-pluckification lost a bunch of my threads and posts on this subject.
The Iridium project has to be the one of the worst business ideas ever. I hope they shot the team at Motorola that initially proposed this project. They spent billions of dollars launching the satellites, only to end up with a global sat phone network that no-one outside of Al-Qaeda wants to use. Seriously, they were building brick phones with a huge antenna that only worked outside. That is, as long as you weren't standing under a tree. This was the same time another group at Motorola was mass-producing the Star-Tac because the general public really did want a phone that was smaller and lighter than all the rest.

Motorola eventually sold off the business for pennies on the dollar.

Hopefully those satellites still have enough fuel for a controlled re-entry.
 
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SpaceForAReason

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Re: Idea for removing space debris

Another idea would be to start a junk yard in orbit where all of the space debris can be located. A fleet of ion tugs could work over a few decades to move the worst of it. Then maybe we could use the parts in space for other stuff.

Or even target specific sats to free up specific orbits for new satellites. Charge the company needing the orbital slot for the removal... hmmm.... I feel a business plan coming on... ;)
 
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EarthlingX

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Re: Idea for removing space debris

SpaceForAReason":379ju3oo said:
Another idea would be to start a junk yard in orbit where all of the space debris can be located. A fleet of ion tugs could work over a few decades to move the worst of it. Then maybe we could use the parts in space for other stuff.

Or even target specific sats to free up specific orbits for new satellites. Charge the company needing the orbital slot for the removal... hmmm.... I feel a business plan coming on... ;)
I like this junkyard idea. A step in the direction of orbital manufacturing, that can be done now.
Here's how:
http://www.spacedaily.com/reports/Space ... d_999.html
by
http://www.launchspace.com/
who also offer some course about space debris in November 2009.

Possible engine space testing starts in 2013:
http://nextbigfuture.com/2009/10/megawa ... ocket.html
In 2013 or 2014, we’ll make clusters of 200-kilowatt engines to give us something close to a megawatt of electricity, and deploy them with a very high-powered solar array. This will be a robotic reusable “space tug” that can refuel or reposition satellites, or even send packages to the Moon at a much lower price.
 
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job1207

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Re: Idea for removing space debris

"When we do long-term projections of the space debris environment, it turns out that space debris mitigation measures will delay, but not prevent, collisional cascading from happening in the low Earth orbit regime," Klinkrad advised. "This is even so if we stop all launching activities right now," he added, and "once that [cascading] process has started there is no way of controlling it again."

"Ailor said that untracked objects — greater than one centimeter in size — are estimated to range between 200,000 and 600,000 bits of flotsam, such as slag from solid rocket motors, liquid metal droplets from nuclear reactors, as well as items like lens covers that are shed during operations.

These objects, most of which flitter through low Earth orbit, are of a size that could take out a satellite, Ailor added, or could reduce the performance of orbiting assets."

From the recent article linked above.








'
 
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samkent

Guest
Re: Idea for removing space debris

A giant foam blob of foam. Have you seen those demos of the expanding foam from a can in the home stores? One can makes one heck of giant blob. Orbit a large container of that (or similar) stuff into an elliptical orbit say 250x 400 miles.

The smaller pieces may imbed themselves if the impact velocity is low enough. The larger/faster ones will have their orbital speed reduced. Eventually it will deorbit itself.
 
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MeteorWayne

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Re: Idea for removing space debris

samkent":27vkwj0z said:
The larger/faster ones will have their orbital speed reduced. Eventually it will deorbit itself.
Or shatter the foam block, releasing thousands of captured pieces and creating thousands more :)
 
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scottb50

Guest
Re: Idea for removing space debris

MeteorWayne":oepozvbd said:
samkent":oepozvbd said:
The larger/faster ones will have their orbital speed reduced. Eventually it will deorbit itself.
Or shatter the foam block, releasing thousands of captured pieces and creating thousands more :)
While it would create more debris it would also be at a lower then initial velocity and be forced from orbit faster. What I see it as is a waste of resources. Just look how much it cost to get that bolt into orbit to begin with? Why get rid of it when it could be re-used in orbit? Solar power is abundantly available and why carry more up when you can make use of what is already there?
 
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wtrix

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Re: Idea for removing space debris

SpaceForAReason":lffgwcm4 said:
Another idea would be to start a junk yard in orbit where all of the space debris can be located. A fleet of ion tugs could work over a few decades to move the worst of it. Then maybe we could use the parts in space for other stuff.

Or even target specific sats to free up specific orbits for new satellites. Charge the company needing the orbital slot for the removal... hmmm.... I feel a business plan coming on... ;)
The problem with the space junkyard idea is that the accumulated pile of rubble tends to spread out over time. So you have to regather it again and again and again,

Instead I think that it is easier to use those serially produced and launched small ion thrusters as retrorockets to lower the orbit of the larger junks faster than it naturally occurs. Remember, the objective is not to clean the space up but to avoid making new trash. And removing old satellites and upper stages makes just that. A few thousand ion thrusters is enough. The problem is - how to attatch the thruster to the deorbitable piece of junk. The problem here is that sometimes the pieces of this junk spin and tumble. Now imagine trying to catch old shuttle main tank that is spinning and tumbling at the same time?

For this purpose I imagined to use a giant "butterfly net". The oversized mouth of the net would be made from pressured soft tube that is pumped up in space. Eyes and mouth of the net would be sized according to the pray. Tumbling tank would of course get the whole system tumbling, but over time the thruster shall be able to gradually slow it down and start to decelerate it. The only problem that I cant conceptually solve here is how to protect the solar panels from braking under exterme loads of fast tumbling and spinning high mass induce centrifugal forces in such a system.
 
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kelvinzero

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Re: Idea for removing space debris

The problem with the space junkyard idea is that the accumulated pile of rubble tends to spread out over time. So you have to regather it again and again and again,
Some sort of tidy-bag would seem to be in order.. :)

I wondered about the junkyard idea a while back.
Initially I was thinking somewhere higher where it would be cheaper it keep in orbit, Now Im thinking lower is better.

You need to pay a lot more in fuel to keep it in orbit, but it is easier to visit and deliver fuel to, and if there is a collision then the resultant fragments would be removed relatively quickly.

Also the fuel cost is not proportional to the mass but the surface area (it only has to counter losses due to atmosphere drag) so a densely packed tank or series of tanks in a line would be much cheaper to keep in orbit than the same mass of station, with its hollow areas and solar panels etc.

Right now this just isn't practical but it could become so as low thrust station-keeping propulsion becomes cheaper. We have VASMIR, and there are also possibilities that don't require bringing along your own propellant
 
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