Recycling Orbital Debris

[shynung]

Trust me, the price of metals obtained this way would be many times higher than the metals obtained on Earth using most expensive methods. This is a futile task you're describing.

If the hunk of metal were to be deorbited and recovered, yes.

In space, it's a different story.

Water on Earth is cheap, for the simple reason that it exists almost everywhere, even though it is quite useful. That same water in space, however, suddenly becomes highly valuable items, because it is needed for a lot of things (namely drinking water, coolant, oxygen, hydrogen fuel, and various chemical processes), yet requires launching them to space, which is expensive. Same goes for practically any other commonly-found items on Earth, metals included.

The premise of this whole idea was to provide raw materials to spacecraft in orbit without the necessities of launching them from Earth. Sure, you can use a fleet of Aquarii to launch spare parts, but finding them on site would have been a lot cheaper.

I'm not talking about debris cleanup here. I'm talking about an ISRU concept (Which is why I mentioned a solar furnace earlier.).

Even if the debris was mostly useless(paint flakes, and the like), as K^2 mentioned, it's still useful as a propellant.

Edited April 21, 2014 by shynung

[ZetaX]

This only works with very very similiar orbits for station and debris, i.e. almost never.

[DoctorCruz]

I'd try laser ablation to push the junk into collection paths with intercepts with a collection vehicle that don't lose momentum. I'd deorbit some of the junk to propel my system. The key thing I'm trying to imagine is what to do with the material other than propulsion. We have limited fabrication capability at this point. Perhaps building that asteroid tug that's been proposed. Junk mass is as good as any mass for that I suppose.

I like this idea, lasers!

[MrZayas1]

I have heard much about this problem, and it does ring my bell a little bit. But in actuality, it does seem as if it would be difficult to recycle one of those flakes of paint wouldn't it? I mean, for things like tanks, inoperable sattelites, that would be much easier, take a probe out to collect the debris, attach a bunch of parachutes to it, and deorbit it. Sadly, much of this costs too much money for too little payment or reserve. Unless you can send something the cost of a pack of paper into orbit, that can do this, it wouldn't interest much to people who are not conservationists. You see, it would be too much of a pain and cost to recycle space debris.

This is why scientists have studied lazer deorbitation, because they can get rid of space debris, and at the same time, save money! Which in all actuality, is better for everyone, and the space programs who don't want to be hit by something going over 1,000 miles per hour! I woudln't either!

[mellojoe]

I think the concept is nice. In practice though, I think there are too many flaws.

Scenario 1) in theory, you have a giant empty fuel tank orbiting and a bunch of thrusters just sitting around. Surely, you could Kludge several of them together to create a useful stage out of existing parts. But, then, you somehow need to get fuel up there. If you are already sending a large amount of fuel, then you already have the tank it is stored in. Therefore, the only real recycling will be the engines themselves. And, well, you already have an engine attached to the fuel you are sending, since you need someway to move the fuel up to the orbiting debris. Therefore, it is not woth it to try to Cobble a bunch of spent stages into a useful stage.

Scenario 2) in theory, you have a bunch of metal and materials floating in space. You want to deorbit them all to gather the materials and recycle them into raw material for manufacturing. Now, we need to send a ship up to capture and deorbit the junk. But where does it land? Do we need to bring a massive heatshild with us to protect the debris? If we deorbit it slowly enough, can we predict where it will land? Can we recover it after it lands? Do we need to bring lots of parachutes to ensure the debris survives impact? Massive, massive costs, and very little return.

Scenario 3) in theory, we have a bunch of crap that needs to be cleaned up. You want to deorbit them and destroy them to keep space clear. Now, reallly, we are just moving trash around. We are moving trash from space onto Earth. There's already a lot of trash on earth. I think many people would argue that instead of bringing more trash to Earth, we should be eliminating trash on Earth by sending it to space. Can we ensure the space debris is burned up? This could yield a decent solution. Turn space debris into ashes. This could also yield a decent solution for cleaning up Earth. Send giant bags of trash to space, then fling them back into the atmosphere to be burned up. But again, massive costs, and potentially massive pollution.

[lajoswinkler]

This only works with very very similiar orbits for station and debris, i.e. almost never.

Ditto.

10c

[ZetaX]

Scenario 3) in theory, we have a bunch of crap that needs to be cleaned up. You want to deorbit them and destroy them to keep space clear. Now, reallly, we are just moving trash around. We are moving trash from space onto Earth. There's already a lot of trash on earth. I think many people would argue that instead of bringing more trash to Earth, we should be eliminating trash on Earth by sending it to space. Can we ensure the space debris is burned up? This could yield a decent solution. Turn space debris into ashes. This could also yield a decent solution for cleaning up Earth. Send giant bags of trash to space, then fling them back into the atmosphere to be burned up. But again, massive costs, and potentially massive pollution.

Not wanting to spoil your plan on countering the evils of vile terranian trash, but why exactly do you think that burning stuff up be sending it up first is in any way preferable to simply burning it where it is: on earth¿

Also, I don't get why some are discussing deorbiting the crap for reusage on earth. It is quite obvious that the marginal amount of rubbish we have orbiting earth is not worth the effort, even if we can do the deorbiting almost for free. Any reuse would either be in space (also doubting viability here, except very special cases, but at least it should be considered) or to avoid Kessler syndrome/other threats.

[mellojoe]

Not wanting to spoil your plan on countering the evils of vile terranian trash, but why exactly do you think that burning stuff up be sending it up first is in any way preferable to simply burning it where it is: on earth¿

Exactly my point. If the whole process is simply to burn something to ashes, we have other means of doing so. The pollution will be similar, just in different layers of atmosphere.

[KASASpace]

Trust me, the price of metals obtained this way would be many times higher than the metals obtained on Earth using most expensive methods. This is a futile task you're describing.

So, then you don't de-orbit the material, unless you needed something on the ground for production.

And, it would cost less, much less. Because of this one thing:

You don't need all that mining equipment, just some electrical power and some NERVAs or VASIMRs, fuel, and some solid rocket motors. All of that on top of spacecraft costs. However, once a vehicle is in space, you don't need to pay much for it, only for communicating and data processing, unless orbital maintenance was done (see Hubble).

Effectively amortizing the costs. Seriously, have you seen the cost of small rocket motors that give just enough Dv to deorbit, in fact all you really need is about 100 m/s (last time I checked, from the Space Shuttles standard orbit.)

[ZetaX]

So you send up tons of fuel, rocket motors (you need one for every deorbiting) and whatever you need to land it safely. All that to deorbit some iron and silicon, i.e. the material the earth is mostly made of, instead of mining it. If that isn't already ridiculous enough for you, add in the already mentioned fact that almost no orbit will be close enough to that station, and most others need ridiculous amounts of fuel to get to.

[Nuke]

in any case i still think we should have a satellite repair station just outside of geo. satellites would be required to have the dv to reach the station at the end of their service life (rather than graveyard orbits). from there you run it like any other recking yard. salvage usable components, recover surplus consumables, cut the remaining material into scrap. sort based on composition and then smash into blocks. the point is to keep that prime geo real-estate clear of debris. and if a future mission needs a part, well then they know where to get it. when space industrialization comes around, the scrap can be reprocessed.

[ZetaX]

That makes more sense (assuming space travel gets cheap enough), but you would still need several such stations (about 10-100 I would guess) to keep that dv low enough to be reasonable. The worst-case dv between two LEO orbits is probably around 15km/s, and its about 6km/s for geostationary orbits, way too much be be reasonable for your average satellite to achieve. That, or satelites are now many times more expensive, plus the higher amount of debris created if something goes wrong by its necessary larger size.

[KASASpace]

So you send up tons of fuel, rocket motors (you need one for every deorbiting) and whatever you need to land it safely. All that to deorbit some iron and silicon, i.e. the material the earth is mostly made of, instead of mining it. If that isn't already ridiculous enough for you, add in the already mentioned fact that almost no orbit will be close enough to that station, and most others need ridiculous amounts of fuel to get to.

So, you send up tons of fuel once every year. Those rocket motors are not used for each piece of debris (unless really large). They are used for de-orbiting specific mass levels. So, you can get a satellite and put it in a container, compress it, align the motors to the center of mass, and release. Or use a mass-driver. However that's a lot of power. Plus, the entire point is that by the time this is implemented space is already effectively industrialized, and thus a bunch of thrown away things, that can be returned over time, would be quite useful.

Not much silicon is used, and in fact, not much iron is used either. Iron is too heavy, aluminum is more common. And guess what about Aluminum: You have to get it from Bauxite. It's much cheaper to use something already in orbit and send some back than to have to pay at least twice as much from South American (or other places) mines.

Look at it this way: The navy manages to keep HUGE carriers in operation, costing billions per year.

The only problem with this is size and length of construction time. A space "dry-dock" would need to be built.

[KASASpace]

The worst-case dv between two LEO orbits is probably around 15km/s, and its about 6km/s for geostationary orbits, way too much be be reasonable for your average satellite to achieve.

And where did you get those values?

Let's look at Gemini, rendezvoused successfully in LEO to a satellite (GATV) with less than 100m/s Dv. And yet you say it takes almost 150 times more?

[dharak1]

What he said was worst case scenario, because if one was in a retrograde orbit and the other was in a proper orbit 9.5km/s for total deorbit and 9.5km/s to get into a prograde orbit. Of course there are way better ways to do it, like getting the retro satellites Ap high up then doing a major burn to flip the orbit up there.

[KASASpace]

What he said was worst case scenario, because if one was in a retrograde orbit and the other was in a proper orbit 9.5km/s for total deorbit and 9.5km/s to get into a prograde orbit. Of course there are way better ways to do it, like getting the retro satellites Ap high up then doing a major burn to flip the orbit up there.

Who in their right mind would launch a satellite in a retrograde orbit and expect it to rendezvous with a prograde orbital path? You would have stations in both types of orbits.

[ZetaX]

@KASASpace: I got these numbers similiar to what dharak1 said; you only need minor amounts of fuel if you already already shoot them into similiar orbits. This is a forum on KSP, did you ever play the game and change inclinations¿

Also, if you are so convinced that this is in any way worth it, show us a sketchy calculation of costs (ideally including the orbit changes, too); just make some guesses on the costs you don't know or depend on future technology (but post them here to let us check plausibility). The aluminium you mention is by the way also one of the cheaper materials, only being a bit more expensive due to the electricity needed. And your carrier-argument is a non-sequitur.

@your newst post: as I said, you will need several stations, way more than just two, as there are other orbits. I don't know a good way to find the actual number, though.

[shynung]

This only works with very very similiar orbits for station and debris, i.e. almost never.

I see. So, the best-case scenario for this kind of thing to work is in graveyard orbits, places where old satellites are moved to at the end of the service life.

P.S. Why do people always think about deorbiting the junk first? Processing them where they already are would have yielded a more convenient solution.

Granted, our fabrication technologies are still limited, so I'm not certain about this being a space junk recycling center for anything else other than aluminium plates.

I'd try laser ablation to push the junk into collection paths with intercepts with a collection vehicle that don't lose momentum. I'd deorbit some of the junk to propel my system. The key thing I'm trying to imagine is what to do with the material other than propulsion. We have limited fabrication capability at this point. Perhaps building that asteroid tug that's been proposed. Junk mass is as good as any mass for that I suppose.

I like this idea. Unfortunately, while it does reduce the performance requirement of the collector vehicle, it does require laser battery installations.

Edited April 22, 2014 by shynung

[mellojoe]

Graveyard Orbit:

De-orbiting a geostationary satellite requires a delta-v of about 1,500 metres per second (4,900 ft/s), whereas re-orbiting it to a graveyard orbit only requires about 11 metres per second (36 ft/s).[*source]

[Seret]

Sounds like the army trying to recycle the bullets the enemy is firing at them by catching them mid flight.

That's about the size of it.

However, what would be considered worthless junk on Earth is actually high-value junk in orbit purely due to the mass-to-orbit cost. At current prices a paperclip in orbit is worth about US$14.

As for 3D printing, it doesn't work that way. You can't just mash up a collection of various different metals and non-metals and feed them to a 3D printer. Sorting the materials accurately, separating them into their component elements (how?) and turning them into a powder suitable for metal ALM would be an incredible process requiring huge amounts of hardware, operating in orbit in zero-g. Not happening in our lifetimes, folks.

Easier just to pick out one easily sortable metal (steel?) and use it to make relatively low-energy low-strength products like extrusions or rolled plates. The poor homogeneity would mean it could only be used for non-critical applications.

[shynung]

As for 3D printing, it doesn't work that way. You can't just mash up a collection of various different metals and non-metals and feed them to a 3D printer. Sorting the materials accurately, separating them into their component elements (how?) and turning them into a powder suitable for metal ALM would be an incredible process requiring huge amounts of hardware, operating in orbit in zero-g. Not happening in our lifetimes, folks.

Easier just to pick out one easily sortable metal (steel?) and use it to make relatively low-energy low-strength products like extrusions or rolled plates. The poor homogeneity would mean it could only be used for non-critical applications.

That's the problem. There isn't any hardware for that yet. Even if there is an industrial technique that could work in micro-g, none have been studied extensively as of yet. Also worthy of note is that all of it must work autonomously, with no humans nearby to fix it when it breaks, all while being showered by junk and debris of various size, shape, mass, and velocity.

Edited April 22, 2014 by shynung

[Dwayne_Knight]

That's about the size of it.

However, what would be considered worthless junk on Earth is actually high-value junk in orbit purely due to the mass-to-orbit cost. At current prices a paperclip in orbit is worth about US$14.

As for 3D printing, it doesn't work that way. You can't just mash up a collection of various different metals and non-metals and feed them to a 3D printer. Sorting the materials accurately, separating them into their component elements (how?) and turning them into a powder suitable for metal ALM would be an incredible process requiring huge amounts of hardware, operating in orbit in zero-g. Not happening in our lifetimes, folks.

Easier just to pick out one easily sortable metal (steel?) and use it to make relatively low-energy low-strength products like extrusions or rolled plates. The poor homogeneity would mean it could only be used for non-critical applications.

Chip it small and agitate it or melt it at slowly raising temperatures spinning it to separate it you should be able to get some useful materials at useful purities.

[ThinkOutsideTheHangar]

It would take too much money and time to actually recover it... one way to get rid of debris is to boost them into a graveyard orbit, above satellites in stationary orbit. They should add some more fuel and control to the upper stages to de-orbit or graveyard orbit them.

[Northstar1989]

Over time, as you may have noticed, space programs leave literally tons of debris in space, particularly near Earth. These range from nuts, bolts, flakes of paint, and fairings to spent upper stages, inoperable satellites, and hapless souls stuck in out-of-fuel pods. Over time, these debris may hinder space operations, or render them impossibly dangerous.

Most proposals that I have read to deal with these debris either simply deorbits them outright, or lower their perigee to hasten orbital decay.

Why can't we simply collect them, I say, and recycle or refurbish it to become new spacecrafts?

We could launch a spacecraft designed to capture these debris. It could either use some sort of mechanism to gather nearby debris, or it could simply wait for incoming debris. It could either gather only useful debris like satellites, upper stages, or things like nuts, bolts, and scrap metal to be used as spare parts for other spacecrafts, or it could use some sort of solar furnace to melt these things and feed it into a 3D printer, making parts for other spacecraft.

I'd like to hear your opinions on the concept.

Not only is it feasible to recycle orbital debris, but I've already actually done it in-game, and, posted it to this forum some time ago... (links and images below...)

First Design- 6 months old: http://forum.kerbalspaceprogram.com/threads/57509-Kerbin-and-Beyond-a-Maturing-Space-Program?p=774155&viewfull=1#post774155

Latest Design- 2 months old: http://forum.kerbalspaceprogram.com/threads/57509-Kerbin-and-Beyond-a-Maturing-Space-Program?p=1051518&viewfull=1#post1051518

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I used the "Recycling Bin" part from Extraplanetary Launchpads, as well as RocketParts storage modules from Orbital Contsruction Re-Redux (due to their higher storage capacities than any of the RocketParts storage parts in Extraplanetary Launchpads- though I find the OCRR parts can store unrealsitically large masses relative to their volume. Ideally, I would like it if there were an extension to ProceduralParts that let me store lots of RocketParts in HUGE containers...)

I use the salvaged RocketParts to, in turn, build things in orbit (like solar farms, modular components for moon-bases, Kethane scanning-satellites, probes, bigger space stations, tankers, and enormous interplanetary vessels to give some possible examples...)

The economics are a bit low-margin, and require use of a stock NERVA engine or better (I used stock NERVA for simplicity, but better ISP can be obtained with KSP-Interstellar or NearFuture mods- with a bit more infrastructure...)

What I basically would do is rendezvous with each and every piece of debris I wanted to recycle, and then fly at it at VERY slow speeds (under 5 m/s for safety) with the Recycling Bin active... This would recycle the debris into an equivalent mass of leftover fuel (if nay were present) and RocketParts- usually at 100% efficiency, although occasionally I experienced bugs where a craft were recycled and did not give me any RocketParts (I consider this realistic since real-life recycling would not be 100% efficient).

What makes this worthwhile economically is that it takes a ENORMOUS amount of energy (fuel) just to get something into low orbit. It takes an *EVEN MORE* ungodly amount of energy (fuel) to get something to an even higher-energy position, like Low Munar (or Lunar, IRL) Orbit, or worse yet, around Duna/Mars or Jool/Jupiter...

Therefore, every single kilogram you can avoid having to ship into orbit (by re-using mass already in orbit) pays for itself with interest- usually it costs a lot less fuel to get the fuel to orbit to rendezvous with a LARGE/MASSIVE/HIGHLY USEFUL piece of debris in orbit (relative to the size of the Scrapper Ship/tug- the more massive the scrapper ship, the more massive/useful the piece of debris has to be to be worth chasing) than it does to ship an equivalent mass to orbit.

The economics improve (both in-game, and would in real-life) the more infrastructure you have in place to support your scrapping operations. I.E. if your Scrapper Ship is powered by a Microwave Beamed Power Satellite that feeds a Thermal Receiver on the Scrapper Ship used for thermal rocketry, your scrapper ship can get more Delta-V from a given fuel mass, and thus spends less fuel harvesting the same debris... If your fuel is produced off-planet through In-Situ Resource Utilization (such as from electrolyzing water-ice or regolith on the Mun/Luna for Hydrogen-Oxygen mix or combustible ratios of Alumina and Oxidizer...), you don't even have to ship any fuel to orbit for the recycling operations, and the operations become *MUCH* more worthwhile.

(Essentially, for the beamed power bit, you heat up a specially-designed heating-coil with large amounts of beamed microwave power from a solar farm or nuclear nuclear reactor on in a stable orbit or on the ground of a planetary body or moon, and passing propellant over the heat, use the thermal expansion of the propellant for high-ISP propulsion, and high thrust with enough beamed power, without any of the mass for energy-generation having to be located on the ship. A variety of propellants can be used in a thermal rocket, including Water, Methane, Liquid Hydrogen, LFO mix- which can be combusted as well as heated by the thermal receiver for additional thrust/ISP, Ammonia, and potentially harvested/stored atmospheric gasses from Kerbin/Earth and Mars/Duna using Thermal Turbojet nozzles in-game...)

Obviously, in real-life (and if running a Life Support mod in the game), without a supporting greenhouse module on a nearby space station to process wastewater, CO2, and fecal matter back into Oxygen, potable water, and food; you really ought to run such a scrapper ship as an unmanned drone. Even with no need to ship up supplies for crew life-support, such a scrapper ship is best run unmanned due to the slow/monotonous nature of the work and high radiation exposure to cosmic rays when performing such operations in higher orbits...

In the version I utilized in my game, there was a single Service Module which could hold a crew member, which allowed me to use KAS winches just to drain leftover fuel rather than recycling the entire piece of debris (using any KAS ports already on the debris, or "drilling" an access port into the duel tanks through attaching a KAS port by KAS' EVA minor construction functionality...), or to pull individual components off the debris via EVA that could be removed with KAS, such as External Command Seats, Ox-STAT solar panels, and the smallest stock radial batteries... Torn-off parts could either be re-used on another ship, or recycled individually rather than recycling the entire ship. It should also be noted that recycling the ship with the Recyclnig Bin would automatically deposit any leftover fuel in the scrapper ship's fuel tanks...

My scrapper ships were all designed before the 0.23.5 update. With the update, it might be more "realistic" (and with *extremely* large pieces of debris that would require MASSIVE storage modules to store all the resources from recycling the debris on-the-spot inside the ship, more mass-efficient) to actually grab onto debris with the "Claw", and haul them back to a space station (I regularly drop off salvaged RocketParts at a space station anyways- to avoid wasting fuel hauling them all over the place to future scrapping operations), where I could feed them to a Recycling Bin there instead of on the ship, and assume from a role-playing perspective that the debris would be more tied down and more slowly/carefully disassembled and recycled by either crew or remote-controlled robots, rather than magically being instantly processed into "RocketParts" that could be stored inside the ship by the Recycling Bin...

Once again, the economics do work, both in real-life and in-game. The technology is feasible (though obviously IRL it would take a bit of engineering to adapt salvaging techniques developed for things like sunken ships to space). And I've actually *DONE IT ALREADY* in-game. So, everybody else, no more calling it "impossible", or "useless", alright?

Regards,

Northstar

Edited May 15, 2014 by Northstar1989

[shynung]

-snip-

You have just described the concept much better than I did.

Though, for some reason, the first thing people think about doing on space junk (even here) is to deorbit them and be done with it. I wonder, why?